mirror of https://github.com/postgres/postgres
detoast.c/h contain functions required to detoast a datum, partially or completely, plus a few other utility functions for examining the size of toasted datums. toast_internals.c/h contain functions that are used internally to the TOAST subsystem but which (mostly) do not need to be accessed from outside. heaptoast.c/h contains code that is intrinsically specific to the heap AM, either because it operates on HeapTuples or is based on the layout of a heap page. detoast.c and toast_internals.c are placed in src/backend/access/common rather than src/backend/access/heap. At present, both files still have dependencies on the heap, but that will be improved in a future commit. Patch by me, reviewed and tested by Prabhat Sabu, Thomas Munro, Andres Freund, and Álvaro Herrera. Discussion: http://postgr.es/m/CA+TgmoZv-=2iWM4jcw5ZhJeL18HF96+W1yJeYrnGMYdkFFnEpQ@mail.gmail.compull/47/head
Robert Haas
6 years ago
parent
74a308cf52
commit
8b94dab066
@ -0,0 +1,869 @@ |
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/*-------------------------------------------------------------------------
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* |
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* detoast.c |
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* Retrieve compressed or external variable size attributes. |
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* |
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* Copyright (c) 2000-2019, PostgreSQL Global Development Group |
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* |
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* IDENTIFICATION |
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* src/backend/access/common/detoast.c |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#include "postgres.h" |
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#include "access/detoast.h" |
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#include "access/genam.h" |
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#include "access/heaptoast.h" |
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#include "access/table.h" |
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#include "access/toast_internals.h" |
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#include "common/pg_lzcompress.h" |
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#include "utils/expandeddatum.h" |
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#include "utils/fmgroids.h" |
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#include "utils/rel.h" |
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static struct varlena *toast_fetch_datum(struct varlena *attr); |
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static struct varlena *toast_fetch_datum_slice(struct varlena *attr, |
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int32 sliceoffset, int32 length); |
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static struct varlena *toast_decompress_datum(struct varlena *attr); |
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static struct varlena *toast_decompress_datum_slice(struct varlena *attr, int32 slicelength); |
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/* ----------
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* heap_tuple_fetch_attr - |
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* |
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* Public entry point to get back a toasted value from |
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* external source (possibly still in compressed format). |
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* |
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* This will return a datum that contains all the data internally, ie, not |
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* relying on external storage or memory, but it can still be compressed or |
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* have a short header. Note some callers assume that if the input is an |
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* EXTERNAL datum, the result will be a pfree'able chunk. |
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* ---------- |
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*/ |
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struct varlena * |
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heap_tuple_fetch_attr(struct varlena *attr) |
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{ |
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struct varlena *result; |
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if (VARATT_IS_EXTERNAL_ONDISK(attr)) |
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{ |
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/*
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* This is an external stored plain value |
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*/ |
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result = toast_fetch_datum(attr); |
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} |
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) |
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{ |
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/*
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* This is an indirect pointer --- dereference it |
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*/ |
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struct varatt_indirect redirect; |
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VARATT_EXTERNAL_GET_POINTER(redirect, attr); |
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attr = (struct varlena *) redirect.pointer; |
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/* nested indirect Datums aren't allowed */ |
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); |
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/* recurse if value is still external in some other way */ |
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if (VARATT_IS_EXTERNAL(attr)) |
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return heap_tuple_fetch_attr(attr); |
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/*
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* Copy into the caller's memory context, in case caller tries to |
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* pfree the result. |
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*/ |
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result = (struct varlena *) palloc(VARSIZE_ANY(attr)); |
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memcpy(result, attr, VARSIZE_ANY(attr)); |
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} |
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else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) |
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{ |
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/*
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* This is an expanded-object pointer --- get flat format |
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*/ |
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ExpandedObjectHeader *eoh; |
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Size resultsize; |
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eoh = DatumGetEOHP(PointerGetDatum(attr)); |
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resultsize = EOH_get_flat_size(eoh); |
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result = (struct varlena *) palloc(resultsize); |
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EOH_flatten_into(eoh, (void *) result, resultsize); |
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} |
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else |
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{ |
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/*
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* This is a plain value inside of the main tuple - why am I called? |
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*/ |
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result = attr; |
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} |
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return result; |
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} |
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/* ----------
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* heap_tuple_untoast_attr - |
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* |
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* Public entry point to get back a toasted value from compression |
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* or external storage. The result is always non-extended varlena form. |
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* |
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* Note some callers assume that if the input is an EXTERNAL or COMPRESSED |
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* datum, the result will be a pfree'able chunk. |
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* ---------- |
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*/ |
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struct varlena * |
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heap_tuple_untoast_attr(struct varlena *attr) |
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{ |
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if (VARATT_IS_EXTERNAL_ONDISK(attr)) |
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{ |
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/*
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* This is an externally stored datum --- fetch it back from there |
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*/ |
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attr = toast_fetch_datum(attr); |
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/* If it's compressed, decompress it */ |
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if (VARATT_IS_COMPRESSED(attr)) |
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{ |
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struct varlena *tmp = attr; |
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attr = toast_decompress_datum(tmp); |
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pfree(tmp); |
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} |
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} |
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) |
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{ |
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/*
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* This is an indirect pointer --- dereference it |
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*/ |
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struct varatt_indirect redirect; |
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VARATT_EXTERNAL_GET_POINTER(redirect, attr); |
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attr = (struct varlena *) redirect.pointer; |
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/* nested indirect Datums aren't allowed */ |
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); |
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/* recurse in case value is still extended in some other way */ |
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attr = heap_tuple_untoast_attr(attr); |
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/* if it isn't, we'd better copy it */ |
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if (attr == (struct varlena *) redirect.pointer) |
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{ |
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struct varlena *result; |
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result = (struct varlena *) palloc(VARSIZE_ANY(attr)); |
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memcpy(result, attr, VARSIZE_ANY(attr)); |
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attr = result; |
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} |
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} |
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else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) |
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{ |
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/*
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* This is an expanded-object pointer --- get flat format |
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*/ |
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attr = heap_tuple_fetch_attr(attr); |
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/* flatteners are not allowed to produce compressed/short output */ |
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Assert(!VARATT_IS_EXTENDED(attr)); |
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} |
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else if (VARATT_IS_COMPRESSED(attr)) |
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{ |
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/*
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* This is a compressed value inside of the main tuple |
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*/ |
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attr = toast_decompress_datum(attr); |
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} |
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else if (VARATT_IS_SHORT(attr)) |
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{ |
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/*
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* This is a short-header varlena --- convert to 4-byte header format |
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*/ |
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Size data_size = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT; |
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Size new_size = data_size + VARHDRSZ; |
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struct varlena *new_attr; |
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new_attr = (struct varlena *) palloc(new_size); |
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SET_VARSIZE(new_attr, new_size); |
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memcpy(VARDATA(new_attr), VARDATA_SHORT(attr), data_size); |
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attr = new_attr; |
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} |
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return attr; |
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} |
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/* ----------
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* heap_tuple_untoast_attr_slice - |
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* |
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* Public entry point to get back part of a toasted value |
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* from compression or external storage. |
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* ---------- |
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*/ |
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struct varlena * |
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heap_tuple_untoast_attr_slice(struct varlena *attr, |
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int32 sliceoffset, int32 slicelength) |
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{ |
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struct varlena *preslice; |
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struct varlena *result; |
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char *attrdata; |
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int32 attrsize; |
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if (VARATT_IS_EXTERNAL_ONDISK(attr)) |
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{ |
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struct varatt_external toast_pointer; |
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
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/* fast path for non-compressed external datums */ |
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if (!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)) |
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return toast_fetch_datum_slice(attr, sliceoffset, slicelength); |
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/* fetch it back (compressed marker will get set automatically) */ |
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preslice = toast_fetch_datum(attr); |
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} |
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else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) |
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{ |
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struct varatt_indirect redirect; |
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VARATT_EXTERNAL_GET_POINTER(redirect, attr); |
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/* nested indirect Datums aren't allowed */ |
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Assert(!VARATT_IS_EXTERNAL_INDIRECT(redirect.pointer)); |
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return heap_tuple_untoast_attr_slice(redirect.pointer, |
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sliceoffset, slicelength); |
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} |
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else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) |
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{ |
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/* pass it off to heap_tuple_fetch_attr to flatten */ |
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preslice = heap_tuple_fetch_attr(attr); |
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} |
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else |
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preslice = attr; |
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Assert(!VARATT_IS_EXTERNAL(preslice)); |
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if (VARATT_IS_COMPRESSED(preslice)) |
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{ |
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struct varlena *tmp = preslice; |
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/* Decompress enough to encompass the slice and the offset */ |
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if (slicelength > 0 && sliceoffset >= 0) |
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preslice = toast_decompress_datum_slice(tmp, slicelength + sliceoffset); |
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else |
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preslice = toast_decompress_datum(tmp); |
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if (tmp != attr) |
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pfree(tmp); |
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} |
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if (VARATT_IS_SHORT(preslice)) |
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{ |
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attrdata = VARDATA_SHORT(preslice); |
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attrsize = VARSIZE_SHORT(preslice) - VARHDRSZ_SHORT; |
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} |
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else |
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{ |
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attrdata = VARDATA(preslice); |
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attrsize = VARSIZE(preslice) - VARHDRSZ; |
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} |
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/* slicing of datum for compressed cases and plain value */ |
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if (sliceoffset >= attrsize) |
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{ |
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sliceoffset = 0; |
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slicelength = 0; |
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} |
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if (((sliceoffset + slicelength) > attrsize) || slicelength < 0) |
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slicelength = attrsize - sliceoffset; |
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result = (struct varlena *) palloc(slicelength + VARHDRSZ); |
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SET_VARSIZE(result, slicelength + VARHDRSZ); |
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memcpy(VARDATA(result), attrdata + sliceoffset, slicelength); |
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if (preslice != attr) |
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pfree(preslice); |
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return result; |
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} |
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/* ----------
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* toast_fetch_datum - |
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* |
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* Reconstruct an in memory Datum from the chunks saved |
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* in the toast relation |
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* ---------- |
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*/ |
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static struct varlena * |
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toast_fetch_datum(struct varlena *attr) |
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{ |
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Relation toastrel; |
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Relation *toastidxs; |
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ScanKeyData toastkey; |
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SysScanDesc toastscan; |
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HeapTuple ttup; |
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TupleDesc toasttupDesc; |
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struct varlena *result; |
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struct varatt_external toast_pointer; |
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int32 ressize; |
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int32 residx, |
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nextidx; |
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int32 numchunks; |
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Pointer chunk; |
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bool isnull; |
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char *chunkdata; |
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int32 chunksize; |
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int num_indexes; |
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int validIndex; |
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SnapshotData SnapshotToast; |
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if (!VARATT_IS_EXTERNAL_ONDISK(attr)) |
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elog(ERROR, "toast_fetch_datum shouldn't be called for non-ondisk datums"); |
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/* Must copy to access aligned fields */ |
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VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
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ressize = toast_pointer.va_extsize; |
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numchunks = ((ressize - 1) / TOAST_MAX_CHUNK_SIZE) + 1; |
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result = (struct varlena *) palloc(ressize + VARHDRSZ); |
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if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)) |
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SET_VARSIZE_COMPRESSED(result, ressize + VARHDRSZ); |
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else |
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SET_VARSIZE(result, ressize + VARHDRSZ); |
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/*
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* Open the toast relation and its indexes |
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*/ |
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toastrel = table_open(toast_pointer.va_toastrelid, AccessShareLock); |
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toasttupDesc = toastrel->rd_att; |
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/* Look for the valid index of the toast relation */ |
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validIndex = toast_open_indexes(toastrel, |
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AccessShareLock, |
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&toastidxs, |
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&num_indexes); |
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/*
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* Setup a scan key to fetch from the index by va_valueid |
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*/ |
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ScanKeyInit(&toastkey, |
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(AttrNumber) 1, |
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BTEqualStrategyNumber, F_OIDEQ, |
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ObjectIdGetDatum(toast_pointer.va_valueid)); |
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/*
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* Read the chunks by index |
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* |
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* Note that because the index is actually on (valueid, chunkidx) we will |
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* see the chunks in chunkidx order, even though we didn't explicitly ask |
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* for it. |
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*/ |
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nextidx = 0; |
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init_toast_snapshot(&SnapshotToast); |
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toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], |
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&SnapshotToast, 1, &toastkey); |
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while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) |
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{ |
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/*
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* Have a chunk, extract the sequence number and the data |
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*/ |
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residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull)); |
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Assert(!isnull); |
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chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull)); |
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Assert(!isnull); |
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if (!VARATT_IS_EXTENDED(chunk)) |
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{ |
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chunksize = VARSIZE(chunk) - VARHDRSZ; |
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chunkdata = VARDATA(chunk); |
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} |
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else if (VARATT_IS_SHORT(chunk)) |
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{ |
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/* could happen due to heap_form_tuple doing its thing */ |
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chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT; |
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chunkdata = VARDATA_SHORT(chunk); |
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} |
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else |
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{ |
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/* should never happen */ |
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elog(ERROR, "found toasted toast chunk for toast value %u in %s", |
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toast_pointer.va_valueid, |
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RelationGetRelationName(toastrel)); |
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chunksize = 0; /* keep compiler quiet */ |
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chunkdata = NULL; |
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} |
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/*
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* Some checks on the data we've found |
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*/ |
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if (residx != nextidx) |
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ereport(ERROR, |
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(errcode(ERRCODE_DATA_CORRUPTED), |
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errmsg_internal("unexpected chunk number %d (expected %d) for toast value %u in %s", |
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residx, nextidx, |
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toast_pointer.va_valueid, |
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RelationGetRelationName(toastrel)))); |
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if (residx < numchunks - 1) |
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{ |
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if (chunksize != TOAST_MAX_CHUNK_SIZE) |
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ereport(ERROR, |
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(errcode(ERRCODE_DATA_CORRUPTED), |
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errmsg_internal("unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s", |
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chunksize, (int) TOAST_MAX_CHUNK_SIZE, |
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residx, numchunks, |
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toast_pointer.va_valueid, |
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RelationGetRelationName(toastrel)))); |
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} |
||||||
|
else if (residx == numchunks - 1) |
||||||
|
{ |
||||||
|
if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != ressize) |
||||||
|
ereport(ERROR, |
||||||
|
(errcode(ERRCODE_DATA_CORRUPTED), |
||||||
|
errmsg_internal("unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s", |
||||||
|
chunksize, |
||||||
|
(int) (ressize - residx * TOAST_MAX_CHUNK_SIZE), |
||||||
|
residx, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)))); |
||||||
|
} |
||||||
|
else |
||||||
|
ereport(ERROR, |
||||||
|
(errcode(ERRCODE_DATA_CORRUPTED), |
||||||
|
errmsg_internal("unexpected chunk number %d (out of range %d..%d) for toast value %u in %s", |
||||||
|
residx, |
||||||
|
0, numchunks - 1, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)))); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Copy the data into proper place in our result |
||||||
|
*/ |
||||||
|
memcpy(VARDATA(result) + residx * TOAST_MAX_CHUNK_SIZE, |
||||||
|
chunkdata, |
||||||
|
chunksize); |
||||||
|
|
||||||
|
nextidx++; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Final checks that we successfully fetched the datum |
||||||
|
*/ |
||||||
|
if (nextidx != numchunks) |
||||||
|
ereport(ERROR, |
||||||
|
(errcode(ERRCODE_DATA_CORRUPTED), |
||||||
|
errmsg_internal("missing chunk number %d for toast value %u in %s", |
||||||
|
nextidx, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)))); |
||||||
|
|
||||||
|
/*
|
||||||
|
* End scan and close relations |
||||||
|
*/ |
||||||
|
systable_endscan_ordered(toastscan); |
||||||
|
toast_close_indexes(toastidxs, num_indexes, AccessShareLock); |
||||||
|
table_close(toastrel, AccessShareLock); |
||||||
|
|
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_fetch_datum_slice - |
||||||
|
* |
||||||
|
* Reconstruct a segment of a Datum from the chunks saved |
||||||
|
* in the toast relation |
||||||
|
* |
||||||
|
* Note that this function only supports non-compressed external datums. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
static struct varlena * |
||||||
|
toast_fetch_datum_slice(struct varlena *attr, int32 sliceoffset, int32 length) |
||||||
|
{ |
||||||
|
Relation toastrel; |
||||||
|
Relation *toastidxs; |
||||||
|
ScanKeyData toastkey[3]; |
||||||
|
int nscankeys; |
||||||
|
SysScanDesc toastscan; |
||||||
|
HeapTuple ttup; |
||||||
|
TupleDesc toasttupDesc; |
||||||
|
struct varlena *result; |
||||||
|
struct varatt_external toast_pointer; |
||||||
|
int32 attrsize; |
||||||
|
int32 residx; |
||||||
|
int32 nextidx; |
||||||
|
int numchunks; |
||||||
|
int startchunk; |
||||||
|
int endchunk; |
||||||
|
int32 startoffset; |
||||||
|
int32 endoffset; |
||||||
|
int totalchunks; |
||||||
|
Pointer chunk; |
||||||
|
bool isnull; |
||||||
|
char *chunkdata; |
||||||
|
int32 chunksize; |
||||||
|
int32 chcpystrt; |
||||||
|
int32 chcpyend; |
||||||
|
int num_indexes; |
||||||
|
int validIndex; |
||||||
|
SnapshotData SnapshotToast; |
||||||
|
|
||||||
|
if (!VARATT_IS_EXTERNAL_ONDISK(attr)) |
||||||
|
elog(ERROR, "toast_fetch_datum_slice shouldn't be called for non-ondisk datums"); |
||||||
|
|
||||||
|
/* Must copy to access aligned fields */ |
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
|
||||||
|
/*
|
||||||
|
* It's nonsense to fetch slices of a compressed datum -- this isn't lo_* |
||||||
|
* we can't return a compressed datum which is meaningful to toast later |
||||||
|
*/ |
||||||
|
Assert(!VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)); |
||||||
|
|
||||||
|
attrsize = toast_pointer.va_extsize; |
||||||
|
totalchunks = ((attrsize - 1) / TOAST_MAX_CHUNK_SIZE) + 1; |
||||||
|
|
||||||
|
if (sliceoffset >= attrsize) |
||||||
|
{ |
||||||
|
sliceoffset = 0; |
||||||
|
length = 0; |
||||||
|
} |
||||||
|
|
||||||
|
if (((sliceoffset + length) > attrsize) || length < 0) |
||||||
|
length = attrsize - sliceoffset; |
||||||
|
|
||||||
|
result = (struct varlena *) palloc(length + VARHDRSZ); |
||||||
|
|
||||||
|
SET_VARSIZE(result, length + VARHDRSZ); |
||||||
|
|
||||||
|
if (length == 0) |
||||||
|
return result; /* Can save a lot of work at this point! */ |
||||||
|
|
||||||
|
startchunk = sliceoffset / TOAST_MAX_CHUNK_SIZE; |
||||||
|
endchunk = (sliceoffset + length - 1) / TOAST_MAX_CHUNK_SIZE; |
||||||
|
numchunks = (endchunk - startchunk) + 1; |
||||||
|
|
||||||
|
startoffset = sliceoffset % TOAST_MAX_CHUNK_SIZE; |
||||||
|
endoffset = (sliceoffset + length - 1) % TOAST_MAX_CHUNK_SIZE; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Open the toast relation and its indexes |
||||||
|
*/ |
||||||
|
toastrel = table_open(toast_pointer.va_toastrelid, AccessShareLock); |
||||||
|
toasttupDesc = toastrel->rd_att; |
||||||
|
|
||||||
|
/* Look for the valid index of toast relation */ |
||||||
|
validIndex = toast_open_indexes(toastrel, |
||||||
|
AccessShareLock, |
||||||
|
&toastidxs, |
||||||
|
&num_indexes); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Setup a scan key to fetch from the index. This is either two keys or |
||||||
|
* three depending on the number of chunks. |
||||||
|
*/ |
||||||
|
ScanKeyInit(&toastkey[0], |
||||||
|
(AttrNumber) 1, |
||||||
|
BTEqualStrategyNumber, F_OIDEQ, |
||||||
|
ObjectIdGetDatum(toast_pointer.va_valueid)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Use equality condition for one chunk, a range condition otherwise: |
||||||
|
*/ |
||||||
|
if (numchunks == 1) |
||||||
|
{ |
||||||
|
ScanKeyInit(&toastkey[1], |
||||||
|
(AttrNumber) 2, |
||||||
|
BTEqualStrategyNumber, F_INT4EQ, |
||||||
|
Int32GetDatum(startchunk)); |
||||||
|
nscankeys = 2; |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
ScanKeyInit(&toastkey[1], |
||||||
|
(AttrNumber) 2, |
||||||
|
BTGreaterEqualStrategyNumber, F_INT4GE, |
||||||
|
Int32GetDatum(startchunk)); |
||||||
|
ScanKeyInit(&toastkey[2], |
||||||
|
(AttrNumber) 2, |
||||||
|
BTLessEqualStrategyNumber, F_INT4LE, |
||||||
|
Int32GetDatum(endchunk)); |
||||||
|
nscankeys = 3; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Read the chunks by index |
||||||
|
* |
||||||
|
* The index is on (valueid, chunkidx) so they will come in order |
||||||
|
*/ |
||||||
|
init_toast_snapshot(&SnapshotToast); |
||||||
|
nextidx = startchunk; |
||||||
|
toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], |
||||||
|
&SnapshotToast, nscankeys, toastkey); |
||||||
|
while ((ttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Have a chunk, extract the sequence number and the data |
||||||
|
*/ |
||||||
|
residx = DatumGetInt32(fastgetattr(ttup, 2, toasttupDesc, &isnull)); |
||||||
|
Assert(!isnull); |
||||||
|
chunk = DatumGetPointer(fastgetattr(ttup, 3, toasttupDesc, &isnull)); |
||||||
|
Assert(!isnull); |
||||||
|
if (!VARATT_IS_EXTENDED(chunk)) |
||||||
|
{ |
||||||
|
chunksize = VARSIZE(chunk) - VARHDRSZ; |
||||||
|
chunkdata = VARDATA(chunk); |
||||||
|
} |
||||||
|
else if (VARATT_IS_SHORT(chunk)) |
||||||
|
{ |
||||||
|
/* could happen due to heap_form_tuple doing its thing */ |
||||||
|
chunksize = VARSIZE_SHORT(chunk) - VARHDRSZ_SHORT; |
||||||
|
chunkdata = VARDATA_SHORT(chunk); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* should never happen */ |
||||||
|
elog(ERROR, "found toasted toast chunk for toast value %u in %s", |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
chunksize = 0; /* keep compiler quiet */ |
||||||
|
chunkdata = NULL; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Some checks on the data we've found |
||||||
|
*/ |
||||||
|
if ((residx != nextidx) || (residx > endchunk) || (residx < startchunk)) |
||||||
|
elog(ERROR, "unexpected chunk number %d (expected %d) for toast value %u in %s", |
||||||
|
residx, nextidx, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
if (residx < totalchunks - 1) |
||||||
|
{ |
||||||
|
if (chunksize != TOAST_MAX_CHUNK_SIZE) |
||||||
|
elog(ERROR, "unexpected chunk size %d (expected %d) in chunk %d of %d for toast value %u in %s when fetching slice", |
||||||
|
chunksize, (int) TOAST_MAX_CHUNK_SIZE, |
||||||
|
residx, totalchunks, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
} |
||||||
|
else if (residx == totalchunks - 1) |
||||||
|
{ |
||||||
|
if ((residx * TOAST_MAX_CHUNK_SIZE + chunksize) != attrsize) |
||||||
|
elog(ERROR, "unexpected chunk size %d (expected %d) in final chunk %d for toast value %u in %s when fetching slice", |
||||||
|
chunksize, |
||||||
|
(int) (attrsize - residx * TOAST_MAX_CHUNK_SIZE), |
||||||
|
residx, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
} |
||||||
|
else |
||||||
|
elog(ERROR, "unexpected chunk number %d (out of range %d..%d) for toast value %u in %s", |
||||||
|
residx, |
||||||
|
0, totalchunks - 1, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Copy the data into proper place in our result |
||||||
|
*/ |
||||||
|
chcpystrt = 0; |
||||||
|
chcpyend = chunksize - 1; |
||||||
|
if (residx == startchunk) |
||||||
|
chcpystrt = startoffset; |
||||||
|
if (residx == endchunk) |
||||||
|
chcpyend = endoffset; |
||||||
|
|
||||||
|
memcpy(VARDATA(result) + |
||||||
|
(residx * TOAST_MAX_CHUNK_SIZE - sliceoffset) + chcpystrt, |
||||||
|
chunkdata + chcpystrt, |
||||||
|
(chcpyend - chcpystrt) + 1); |
||||||
|
|
||||||
|
nextidx++; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Final checks that we successfully fetched the datum |
||||||
|
*/ |
||||||
|
if (nextidx != (endchunk + 1)) |
||||||
|
elog(ERROR, "missing chunk number %d for toast value %u in %s", |
||||||
|
nextidx, |
||||||
|
toast_pointer.va_valueid, |
||||||
|
RelationGetRelationName(toastrel)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* End scan and close relations |
||||||
|
*/ |
||||||
|
systable_endscan_ordered(toastscan); |
||||||
|
toast_close_indexes(toastidxs, num_indexes, AccessShareLock); |
||||||
|
table_close(toastrel, AccessShareLock); |
||||||
|
|
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_decompress_datum - |
||||||
|
* |
||||||
|
* Decompress a compressed version of a varlena datum |
||||||
|
*/ |
||||||
|
static struct varlena * |
||||||
|
toast_decompress_datum(struct varlena *attr) |
||||||
|
{ |
||||||
|
struct varlena *result; |
||||||
|
|
||||||
|
Assert(VARATT_IS_COMPRESSED(attr)); |
||||||
|
|
||||||
|
result = (struct varlena *) |
||||||
|
palloc(TOAST_COMPRESS_RAWSIZE(attr) + VARHDRSZ); |
||||||
|
SET_VARSIZE(result, TOAST_COMPRESS_RAWSIZE(attr) + VARHDRSZ); |
||||||
|
|
||||||
|
if (pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), |
||||||
|
VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, |
||||||
|
VARDATA(result), |
||||||
|
TOAST_COMPRESS_RAWSIZE(attr), true) < 0) |
||||||
|
elog(ERROR, "compressed data is corrupted"); |
||||||
|
|
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_decompress_datum_slice - |
||||||
|
* |
||||||
|
* Decompress the front of a compressed version of a varlena datum. |
||||||
|
* offset handling happens in heap_tuple_untoast_attr_slice. |
||||||
|
* Here we just decompress a slice from the front. |
||||||
|
*/ |
||||||
|
static struct varlena * |
||||||
|
toast_decompress_datum_slice(struct varlena *attr, int32 slicelength) |
||||||
|
{ |
||||||
|
struct varlena *result; |
||||||
|
int32 rawsize; |
||||||
|
|
||||||
|
Assert(VARATT_IS_COMPRESSED(attr)); |
||||||
|
|
||||||
|
result = (struct varlena *) palloc(slicelength + VARHDRSZ); |
||||||
|
|
||||||
|
rawsize = pglz_decompress(TOAST_COMPRESS_RAWDATA(attr), |
||||||
|
VARSIZE(attr) - TOAST_COMPRESS_HDRSZ, |
||||||
|
VARDATA(result), |
||||||
|
slicelength, false); |
||||||
|
if (rawsize < 0) |
||||||
|
elog(ERROR, "compressed data is corrupted"); |
||||||
|
|
||||||
|
SET_VARSIZE(result, rawsize + VARHDRSZ); |
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_raw_datum_size - |
||||||
|
* |
||||||
|
* Return the raw (detoasted) size of a varlena datum |
||||||
|
* (including the VARHDRSZ header) |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
Size |
||||||
|
toast_raw_datum_size(Datum value) |
||||||
|
{ |
||||||
|
struct varlena *attr = (struct varlena *) DatumGetPointer(value); |
||||||
|
Size result; |
||||||
|
|
||||||
|
if (VARATT_IS_EXTERNAL_ONDISK(attr)) |
||||||
|
{ |
||||||
|
/* va_rawsize is the size of the original datum -- including header */ |
||||||
|
struct varatt_external toast_pointer; |
||||||
|
|
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
result = toast_pointer.va_rawsize; |
||||||
|
} |
||||||
|
else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) |
||||||
|
{ |
||||||
|
struct varatt_indirect toast_pointer; |
||||||
|
|
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
|
||||||
|
/* nested indirect Datums aren't allowed */ |
||||||
|
Assert(!VARATT_IS_EXTERNAL_INDIRECT(toast_pointer.pointer)); |
||||||
|
|
||||||
|
return toast_raw_datum_size(PointerGetDatum(toast_pointer.pointer)); |
||||||
|
} |
||||||
|
else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) |
||||||
|
{ |
||||||
|
result = EOH_get_flat_size(DatumGetEOHP(value)); |
||||||
|
} |
||||||
|
else if (VARATT_IS_COMPRESSED(attr)) |
||||||
|
{ |
||||||
|
/* here, va_rawsize is just the payload size */ |
||||||
|
result = VARRAWSIZE_4B_C(attr) + VARHDRSZ; |
||||||
|
} |
||||||
|
else if (VARATT_IS_SHORT(attr)) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* we have to normalize the header length to VARHDRSZ or else the |
||||||
|
* callers of this function will be confused. |
||||||
|
*/ |
||||||
|
result = VARSIZE_SHORT(attr) - VARHDRSZ_SHORT + VARHDRSZ; |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* plain untoasted datum */ |
||||||
|
result = VARSIZE(attr); |
||||||
|
} |
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_datum_size |
||||||
|
* |
||||||
|
* Return the physical storage size (possibly compressed) of a varlena datum |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
Size |
||||||
|
toast_datum_size(Datum value) |
||||||
|
{ |
||||||
|
struct varlena *attr = (struct varlena *) DatumGetPointer(value); |
||||||
|
Size result; |
||||||
|
|
||||||
|
if (VARATT_IS_EXTERNAL_ONDISK(attr)) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Attribute is stored externally - return the extsize whether |
||||||
|
* compressed or not. We do not count the size of the toast pointer |
||||||
|
* ... should we? |
||||||
|
*/ |
||||||
|
struct varatt_external toast_pointer; |
||||||
|
|
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
result = toast_pointer.va_extsize; |
||||||
|
} |
||||||
|
else if (VARATT_IS_EXTERNAL_INDIRECT(attr)) |
||||||
|
{ |
||||||
|
struct varatt_indirect toast_pointer; |
||||||
|
|
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
|
||||||
|
/* nested indirect Datums aren't allowed */ |
||||||
|
Assert(!VARATT_IS_EXTERNAL_INDIRECT(attr)); |
||||||
|
|
||||||
|
return toast_datum_size(PointerGetDatum(toast_pointer.pointer)); |
||||||
|
} |
||||||
|
else if (VARATT_IS_EXTERNAL_EXPANDED(attr)) |
||||||
|
{ |
||||||
|
result = EOH_get_flat_size(DatumGetEOHP(value)); |
||||||
|
} |
||||||
|
else if (VARATT_IS_SHORT(attr)) |
||||||
|
{ |
||||||
|
result = VARSIZE_SHORT(attr); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Attribute is stored inline either compressed or not, just calculate |
||||||
|
* the size of the datum in either case. |
||||||
|
*/ |
||||||
|
result = VARSIZE(attr); |
||||||
|
} |
||||||
|
return result; |
||||||
|
} |
||||||
@ -0,0 +1,632 @@ |
|||||||
|
/*-------------------------------------------------------------------------
|
||||||
|
* |
||||||
|
* toast_internals.c |
||||||
|
* Functions for internal use by the TOAST system. |
||||||
|
* |
||||||
|
* Copyright (c) 2000-2019, PostgreSQL Global Development Group |
||||||
|
* |
||||||
|
* IDENTIFICATION |
||||||
|
* src/backend/access/common/toast_internals.c |
||||||
|
* |
||||||
|
*------------------------------------------------------------------------- |
||||||
|
*/ |
||||||
|
|
||||||
|
#include "postgres.h" |
||||||
|
|
||||||
|
#include "access/detoast.h" |
||||||
|
#include "access/genam.h" |
||||||
|
#include "access/heapam.h" |
||||||
|
#include "access/heaptoast.h" |
||||||
|
#include "access/table.h" |
||||||
|
#include "access/toast_internals.h" |
||||||
|
#include "access/xact.h" |
||||||
|
#include "catalog/catalog.h" |
||||||
|
#include "common/pg_lzcompress.h" |
||||||
|
#include "miscadmin.h" |
||||||
|
#include "utils/fmgroids.h" |
||||||
|
#include "utils/rel.h" |
||||||
|
#include "utils/snapmgr.h" |
||||||
|
|
||||||
|
static bool toastrel_valueid_exists(Relation toastrel, Oid valueid); |
||||||
|
static bool toastid_valueid_exists(Oid toastrelid, Oid valueid); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_compress_datum - |
||||||
|
* |
||||||
|
* Create a compressed version of a varlena datum |
||||||
|
* |
||||||
|
* If we fail (ie, compressed result is actually bigger than original) |
||||||
|
* then return NULL. We must not use compressed data if it'd expand |
||||||
|
* the tuple! |
||||||
|
* |
||||||
|
* We use VAR{SIZE,DATA}_ANY so we can handle short varlenas here without |
||||||
|
* copying them. But we can't handle external or compressed datums. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
Datum |
||||||
|
toast_compress_datum(Datum value) |
||||||
|
{ |
||||||
|
struct varlena *tmp; |
||||||
|
int32 valsize = VARSIZE_ANY_EXHDR(DatumGetPointer(value)); |
||||||
|
int32 len; |
||||||
|
|
||||||
|
Assert(!VARATT_IS_EXTERNAL(DatumGetPointer(value))); |
||||||
|
Assert(!VARATT_IS_COMPRESSED(DatumGetPointer(value))); |
||||||
|
|
||||||
|
/*
|
||||||
|
* No point in wasting a palloc cycle if value size is out of the allowed |
||||||
|
* range for compression |
||||||
|
*/ |
||||||
|
if (valsize < PGLZ_strategy_default->min_input_size || |
||||||
|
valsize > PGLZ_strategy_default->max_input_size) |
||||||
|
return PointerGetDatum(NULL); |
||||||
|
|
||||||
|
tmp = (struct varlena *) palloc(PGLZ_MAX_OUTPUT(valsize) + |
||||||
|
TOAST_COMPRESS_HDRSZ); |
||||||
|
|
||||||
|
/*
|
||||||
|
* We recheck the actual size even if pglz_compress() reports success, |
||||||
|
* because it might be satisfied with having saved as little as one byte |
||||||
|
* in the compressed data --- which could turn into a net loss once you |
||||||
|
* consider header and alignment padding. Worst case, the compressed |
||||||
|
* format might require three padding bytes (plus header, which is |
||||||
|
* included in VARSIZE(tmp)), whereas the uncompressed format would take |
||||||
|
* only one header byte and no padding if the value is short enough. So |
||||||
|
* we insist on a savings of more than 2 bytes to ensure we have a gain. |
||||||
|
*/ |
||||||
|
len = pglz_compress(VARDATA_ANY(DatumGetPointer(value)), |
||||||
|
valsize, |
||||||
|
TOAST_COMPRESS_RAWDATA(tmp), |
||||||
|
PGLZ_strategy_default); |
||||||
|
if (len >= 0 && |
||||||
|
len + TOAST_COMPRESS_HDRSZ < valsize - 2) |
||||||
|
{ |
||||||
|
TOAST_COMPRESS_SET_RAWSIZE(tmp, valsize); |
||||||
|
SET_VARSIZE_COMPRESSED(tmp, len + TOAST_COMPRESS_HDRSZ); |
||||||
|
/* successful compression */ |
||||||
|
return PointerGetDatum(tmp); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* incompressible data */ |
||||||
|
pfree(tmp); |
||||||
|
return PointerGetDatum(NULL); |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_save_datum - |
||||||
|
* |
||||||
|
* Save one single datum into the secondary relation and return |
||||||
|
* a Datum reference for it. |
||||||
|
* |
||||||
|
* rel: the main relation we're working with (not the toast rel!) |
||||||
|
* value: datum to be pushed to toast storage |
||||||
|
* oldexternal: if not NULL, toast pointer previously representing the datum |
||||||
|
* options: options to be passed to heap_insert() for toast rows |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
Datum |
||||||
|
toast_save_datum(Relation rel, Datum value, |
||||||
|
struct varlena *oldexternal, int options) |
||||||
|
{ |
||||||
|
Relation toastrel; |
||||||
|
Relation *toastidxs; |
||||||
|
HeapTuple toasttup; |
||||||
|
TupleDesc toasttupDesc; |
||||||
|
Datum t_values[3]; |
||||||
|
bool t_isnull[3]; |
||||||
|
CommandId mycid = GetCurrentCommandId(true); |
||||||
|
struct varlena *result; |
||||||
|
struct varatt_external toast_pointer; |
||||||
|
union |
||||||
|
{ |
||||||
|
struct varlena hdr; |
||||||
|
/* this is to make the union big enough for a chunk: */ |
||||||
|
char data[TOAST_MAX_CHUNK_SIZE + VARHDRSZ]; |
||||||
|
/* ensure union is aligned well enough: */ |
||||||
|
int32 align_it; |
||||||
|
} chunk_data; |
||||||
|
int32 chunk_size; |
||||||
|
int32 chunk_seq = 0; |
||||||
|
char *data_p; |
||||||
|
int32 data_todo; |
||||||
|
Pointer dval = DatumGetPointer(value); |
||||||
|
int num_indexes; |
||||||
|
int validIndex; |
||||||
|
|
||||||
|
Assert(!VARATT_IS_EXTERNAL(value)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Open the toast relation and its indexes. We can use the index to check |
||||||
|
* uniqueness of the OID we assign to the toasted item, even though it has |
||||||
|
* additional columns besides OID. |
||||||
|
*/ |
||||||
|
toastrel = table_open(rel->rd_rel->reltoastrelid, RowExclusiveLock); |
||||||
|
toasttupDesc = toastrel->rd_att; |
||||||
|
|
||||||
|
/* Open all the toast indexes and look for the valid one */ |
||||||
|
validIndex = toast_open_indexes(toastrel, |
||||||
|
RowExclusiveLock, |
||||||
|
&toastidxs, |
||||||
|
&num_indexes); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Get the data pointer and length, and compute va_rawsize and va_extsize. |
||||||
|
* |
||||||
|
* va_rawsize is the size of the equivalent fully uncompressed datum, so |
||||||
|
* we have to adjust for short headers. |
||||||
|
* |
||||||
|
* va_extsize is the actual size of the data payload in the toast records. |
||||||
|
*/ |
||||||
|
if (VARATT_IS_SHORT(dval)) |
||||||
|
{ |
||||||
|
data_p = VARDATA_SHORT(dval); |
||||||
|
data_todo = VARSIZE_SHORT(dval) - VARHDRSZ_SHORT; |
||||||
|
toast_pointer.va_rawsize = data_todo + VARHDRSZ; /* as if not short */ |
||||||
|
toast_pointer.va_extsize = data_todo; |
||||||
|
} |
||||||
|
else if (VARATT_IS_COMPRESSED(dval)) |
||||||
|
{ |
||||||
|
data_p = VARDATA(dval); |
||||||
|
data_todo = VARSIZE(dval) - VARHDRSZ; |
||||||
|
/* rawsize in a compressed datum is just the size of the payload */ |
||||||
|
toast_pointer.va_rawsize = VARRAWSIZE_4B_C(dval) + VARHDRSZ; |
||||||
|
toast_pointer.va_extsize = data_todo; |
||||||
|
/* Assert that the numbers look like it's compressed */ |
||||||
|
Assert(VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer)); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
data_p = VARDATA(dval); |
||||||
|
data_todo = VARSIZE(dval) - VARHDRSZ; |
||||||
|
toast_pointer.va_rawsize = VARSIZE(dval); |
||||||
|
toast_pointer.va_extsize = data_todo; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Insert the correct table OID into the result TOAST pointer. |
||||||
|
* |
||||||
|
* Normally this is the actual OID of the target toast table, but during |
||||||
|
* table-rewriting operations such as CLUSTER, we have to insert the OID |
||||||
|
* of the table's real permanent toast table instead. rd_toastoid is set |
||||||
|
* if we have to substitute such an OID. |
||||||
|
*/ |
||||||
|
if (OidIsValid(rel->rd_toastoid)) |
||||||
|
toast_pointer.va_toastrelid = rel->rd_toastoid; |
||||||
|
else |
||||||
|
toast_pointer.va_toastrelid = RelationGetRelid(toastrel); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Choose an OID to use as the value ID for this toast value. |
||||||
|
* |
||||||
|
* Normally we just choose an unused OID within the toast table. But |
||||||
|
* during table-rewriting operations where we are preserving an existing |
||||||
|
* toast table OID, we want to preserve toast value OIDs too. So, if |
||||||
|
* rd_toastoid is set and we had a prior external value from that same |
||||||
|
* toast table, re-use its value ID. If we didn't have a prior external |
||||||
|
* value (which is a corner case, but possible if the table's attstorage |
||||||
|
* options have been changed), we have to pick a value ID that doesn't |
||||||
|
* conflict with either new or existing toast value OIDs. |
||||||
|
*/ |
||||||
|
if (!OidIsValid(rel->rd_toastoid)) |
||||||
|
{ |
||||||
|
/* normal case: just choose an unused OID */ |
||||||
|
toast_pointer.va_valueid = |
||||||
|
GetNewOidWithIndex(toastrel, |
||||||
|
RelationGetRelid(toastidxs[validIndex]), |
||||||
|
(AttrNumber) 1); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* rewrite case: check to see if value was in old toast table */ |
||||||
|
toast_pointer.va_valueid = InvalidOid; |
||||||
|
if (oldexternal != NULL) |
||||||
|
{ |
||||||
|
struct varatt_external old_toast_pointer; |
||||||
|
|
||||||
|
Assert(VARATT_IS_EXTERNAL_ONDISK(oldexternal)); |
||||||
|
/* Must copy to access aligned fields */ |
||||||
|
VARATT_EXTERNAL_GET_POINTER(old_toast_pointer, oldexternal); |
||||||
|
if (old_toast_pointer.va_toastrelid == rel->rd_toastoid) |
||||||
|
{ |
||||||
|
/* This value came from the old toast table; reuse its OID */ |
||||||
|
toast_pointer.va_valueid = old_toast_pointer.va_valueid; |
||||||
|
|
||||||
|
/*
|
||||||
|
* There is a corner case here: the table rewrite might have |
||||||
|
* to copy both live and recently-dead versions of a row, and |
||||||
|
* those versions could easily reference the same toast value. |
||||||
|
* When we copy the second or later version of such a row, |
||||||
|
* reusing the OID will mean we select an OID that's already |
||||||
|
* in the new toast table. Check for that, and if so, just |
||||||
|
* fall through without writing the data again. |
||||||
|
* |
||||||
|
* While annoying and ugly-looking, this is a good thing |
||||||
|
* because it ensures that we wind up with only one copy of |
||||||
|
* the toast value when there is only one copy in the old |
||||||
|
* toast table. Before we detected this case, we'd have made |
||||||
|
* multiple copies, wasting space; and what's worse, the |
||||||
|
* copies belonging to already-deleted heap tuples would not |
||||||
|
* be reclaimed by VACUUM. |
||||||
|
*/ |
||||||
|
if (toastrel_valueid_exists(toastrel, |
||||||
|
toast_pointer.va_valueid)) |
||||||
|
{ |
||||||
|
/* Match, so short-circuit the data storage loop below */ |
||||||
|
data_todo = 0; |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
if (toast_pointer.va_valueid == InvalidOid) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* new value; must choose an OID that doesn't conflict in either |
||||||
|
* old or new toast table |
||||||
|
*/ |
||||||
|
do |
||||||
|
{ |
||||||
|
toast_pointer.va_valueid = |
||||||
|
GetNewOidWithIndex(toastrel, |
||||||
|
RelationGetRelid(toastidxs[validIndex]), |
||||||
|
(AttrNumber) 1); |
||||||
|
} while (toastid_valueid_exists(rel->rd_toastoid, |
||||||
|
toast_pointer.va_valueid)); |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Initialize constant parts of the tuple data |
||||||
|
*/ |
||||||
|
t_values[0] = ObjectIdGetDatum(toast_pointer.va_valueid); |
||||||
|
t_values[2] = PointerGetDatum(&chunk_data); |
||||||
|
t_isnull[0] = false; |
||||||
|
t_isnull[1] = false; |
||||||
|
t_isnull[2] = false; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Split up the item into chunks |
||||||
|
*/ |
||||||
|
while (data_todo > 0) |
||||||
|
{ |
||||||
|
int i; |
||||||
|
|
||||||
|
CHECK_FOR_INTERRUPTS(); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Calculate the size of this chunk |
||||||
|
*/ |
||||||
|
chunk_size = Min(TOAST_MAX_CHUNK_SIZE, data_todo); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Build a tuple and store it |
||||||
|
*/ |
||||||
|
t_values[1] = Int32GetDatum(chunk_seq++); |
||||||
|
SET_VARSIZE(&chunk_data, chunk_size + VARHDRSZ); |
||||||
|
memcpy(VARDATA(&chunk_data), data_p, chunk_size); |
||||||
|
toasttup = heap_form_tuple(toasttupDesc, t_values, t_isnull); |
||||||
|
|
||||||
|
heap_insert(toastrel, toasttup, mycid, options, NULL); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Create the index entry. We cheat a little here by not using |
||||||
|
* FormIndexDatum: this relies on the knowledge that the index columns |
||||||
|
* are the same as the initial columns of the table for all the |
||||||
|
* indexes. We also cheat by not providing an IndexInfo: this is okay |
||||||
|
* for now because btree doesn't need one, but we might have to be |
||||||
|
* more honest someday. |
||||||
|
* |
||||||
|
* Note also that there had better not be any user-created index on |
||||||
|
* the TOAST table, since we don't bother to update anything else. |
||||||
|
*/ |
||||||
|
for (i = 0; i < num_indexes; i++) |
||||||
|
{ |
||||||
|
/* Only index relations marked as ready can be updated */ |
||||||
|
if (toastidxs[i]->rd_index->indisready) |
||||||
|
index_insert(toastidxs[i], t_values, t_isnull, |
||||||
|
&(toasttup->t_self), |
||||||
|
toastrel, |
||||||
|
toastidxs[i]->rd_index->indisunique ? |
||||||
|
UNIQUE_CHECK_YES : UNIQUE_CHECK_NO, |
||||||
|
NULL); |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free memory |
||||||
|
*/ |
||||||
|
heap_freetuple(toasttup); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Move on to next chunk |
||||||
|
*/ |
||||||
|
data_todo -= chunk_size; |
||||||
|
data_p += chunk_size; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Done - close toast relation and its indexes |
||||||
|
*/ |
||||||
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); |
||||||
|
table_close(toastrel, RowExclusiveLock); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Create the TOAST pointer value that we'll return |
||||||
|
*/ |
||||||
|
result = (struct varlena *) palloc(TOAST_POINTER_SIZE); |
||||||
|
SET_VARTAG_EXTERNAL(result, VARTAG_ONDISK); |
||||||
|
memcpy(VARDATA_EXTERNAL(result), &toast_pointer, sizeof(toast_pointer)); |
||||||
|
|
||||||
|
return PointerGetDatum(result); |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_delete_datum - |
||||||
|
* |
||||||
|
* Delete a single external stored value. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
void |
||||||
|
toast_delete_datum(Relation rel, Datum value, bool is_speculative) |
||||||
|
{ |
||||||
|
struct varlena *attr = (struct varlena *) DatumGetPointer(value); |
||||||
|
struct varatt_external toast_pointer; |
||||||
|
Relation toastrel; |
||||||
|
Relation *toastidxs; |
||||||
|
ScanKeyData toastkey; |
||||||
|
SysScanDesc toastscan; |
||||||
|
HeapTuple toasttup; |
||||||
|
int num_indexes; |
||||||
|
int validIndex; |
||||||
|
SnapshotData SnapshotToast; |
||||||
|
|
||||||
|
if (!VARATT_IS_EXTERNAL_ONDISK(attr)) |
||||||
|
return; |
||||||
|
|
||||||
|
/* Must copy to access aligned fields */ |
||||||
|
VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Open the toast relation and its indexes |
||||||
|
*/ |
||||||
|
toastrel = table_open(toast_pointer.va_toastrelid, RowExclusiveLock); |
||||||
|
|
||||||
|
/* Fetch valid relation used for process */ |
||||||
|
validIndex = toast_open_indexes(toastrel, |
||||||
|
RowExclusiveLock, |
||||||
|
&toastidxs, |
||||||
|
&num_indexes); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Setup a scan key to find chunks with matching va_valueid |
||||||
|
*/ |
||||||
|
ScanKeyInit(&toastkey, |
||||||
|
(AttrNumber) 1, |
||||||
|
BTEqualStrategyNumber, F_OIDEQ, |
||||||
|
ObjectIdGetDatum(toast_pointer.va_valueid)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Find all the chunks. (We don't actually care whether we see them in |
||||||
|
* sequence or not, but since we've already locked the index we might as |
||||||
|
* well use systable_beginscan_ordered.) |
||||||
|
*/ |
||||||
|
init_toast_snapshot(&SnapshotToast); |
||||||
|
toastscan = systable_beginscan_ordered(toastrel, toastidxs[validIndex], |
||||||
|
&SnapshotToast, 1, &toastkey); |
||||||
|
while ((toasttup = systable_getnext_ordered(toastscan, ForwardScanDirection)) != NULL) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Have a chunk, delete it |
||||||
|
*/ |
||||||
|
if (is_speculative) |
||||||
|
heap_abort_speculative(toastrel, &toasttup->t_self); |
||||||
|
else |
||||||
|
simple_heap_delete(toastrel, &toasttup->t_self); |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* End scan and close relations |
||||||
|
*/ |
||||||
|
systable_endscan_ordered(toastscan); |
||||||
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); |
||||||
|
table_close(toastrel, RowExclusiveLock); |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toastrel_valueid_exists - |
||||||
|
* |
||||||
|
* Test whether a toast value with the given ID exists in the toast relation. |
||||||
|
* For safety, we consider a value to exist if there are either live or dead |
||||||
|
* toast rows with that ID; see notes for GetNewOidWithIndex(). |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
static bool |
||||||
|
toastrel_valueid_exists(Relation toastrel, Oid valueid) |
||||||
|
{ |
||||||
|
bool result = false; |
||||||
|
ScanKeyData toastkey; |
||||||
|
SysScanDesc toastscan; |
||||||
|
int num_indexes; |
||||||
|
int validIndex; |
||||||
|
Relation *toastidxs; |
||||||
|
|
||||||
|
/* Fetch a valid index relation */ |
||||||
|
validIndex = toast_open_indexes(toastrel, |
||||||
|
RowExclusiveLock, |
||||||
|
&toastidxs, |
||||||
|
&num_indexes); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Setup a scan key to find chunks with matching va_valueid |
||||||
|
*/ |
||||||
|
ScanKeyInit(&toastkey, |
||||||
|
(AttrNumber) 1, |
||||||
|
BTEqualStrategyNumber, F_OIDEQ, |
||||||
|
ObjectIdGetDatum(valueid)); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Is there any such chunk? |
||||||
|
*/ |
||||||
|
toastscan = systable_beginscan(toastrel, |
||||||
|
RelationGetRelid(toastidxs[validIndex]), |
||||||
|
true, SnapshotAny, 1, &toastkey); |
||||||
|
|
||||||
|
if (systable_getnext(toastscan) != NULL) |
||||||
|
result = true; |
||||||
|
|
||||||
|
systable_endscan(toastscan); |
||||||
|
|
||||||
|
/* Clean up */ |
||||||
|
toast_close_indexes(toastidxs, num_indexes, RowExclusiveLock); |
||||||
|
|
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toastid_valueid_exists - |
||||||
|
* |
||||||
|
* As above, but work from toast rel's OID not an open relation |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
static bool |
||||||
|
toastid_valueid_exists(Oid toastrelid, Oid valueid) |
||||||
|
{ |
||||||
|
bool result; |
||||||
|
Relation toastrel; |
||||||
|
|
||||||
|
toastrel = table_open(toastrelid, AccessShareLock); |
||||||
|
|
||||||
|
result = toastrel_valueid_exists(toastrel, valueid); |
||||||
|
|
||||||
|
table_close(toastrel, AccessShareLock); |
||||||
|
|
||||||
|
return result; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_get_valid_index |
||||||
|
* |
||||||
|
* Get OID of valid index associated to given toast relation. A toast |
||||||
|
* relation can have only one valid index at the same time. |
||||||
|
*/ |
||||||
|
Oid |
||||||
|
toast_get_valid_index(Oid toastoid, LOCKMODE lock) |
||||||
|
{ |
||||||
|
int num_indexes; |
||||||
|
int validIndex; |
||||||
|
Oid validIndexOid; |
||||||
|
Relation *toastidxs; |
||||||
|
Relation toastrel; |
||||||
|
|
||||||
|
/* Open the toast relation */ |
||||||
|
toastrel = table_open(toastoid, lock); |
||||||
|
|
||||||
|
/* Look for the valid index of the toast relation */ |
||||||
|
validIndex = toast_open_indexes(toastrel, |
||||||
|
lock, |
||||||
|
&toastidxs, |
||||||
|
&num_indexes); |
||||||
|
validIndexOid = RelationGetRelid(toastidxs[validIndex]); |
||||||
|
|
||||||
|
/* Close the toast relation and all its indexes */ |
||||||
|
toast_close_indexes(toastidxs, num_indexes, lock); |
||||||
|
table_close(toastrel, lock); |
||||||
|
|
||||||
|
return validIndexOid; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_open_indexes |
||||||
|
* |
||||||
|
* Get an array of the indexes associated to the given toast relation |
||||||
|
* and return as well the position of the valid index used by the toast |
||||||
|
* relation in this array. It is the responsibility of the caller of this |
||||||
|
* function to close the indexes as well as free them. |
||||||
|
*/ |
||||||
|
int |
||||||
|
toast_open_indexes(Relation toastrel, |
||||||
|
LOCKMODE lock, |
||||||
|
Relation **toastidxs, |
||||||
|
int *num_indexes) |
||||||
|
{ |
||||||
|
int i = 0; |
||||||
|
int res = 0; |
||||||
|
bool found = false; |
||||||
|
List *indexlist; |
||||||
|
ListCell *lc; |
||||||
|
|
||||||
|
/* Get index list of the toast relation */ |
||||||
|
indexlist = RelationGetIndexList(toastrel); |
||||||
|
Assert(indexlist != NIL); |
||||||
|
|
||||||
|
*num_indexes = list_length(indexlist); |
||||||
|
|
||||||
|
/* Open all the index relations */ |
||||||
|
*toastidxs = (Relation *) palloc(*num_indexes * sizeof(Relation)); |
||||||
|
foreach(lc, indexlist) |
||||||
|
(*toastidxs)[i++] = index_open(lfirst_oid(lc), lock); |
||||||
|
|
||||||
|
/* Fetch the first valid index in list */ |
||||||
|
for (i = 0; i < *num_indexes; i++) |
||||||
|
{ |
||||||
|
Relation toastidx = (*toastidxs)[i]; |
||||||
|
|
||||||
|
if (toastidx->rd_index->indisvalid) |
||||||
|
{ |
||||||
|
res = i; |
||||||
|
found = true; |
||||||
|
break; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free index list, not necessary anymore as relations are opened and a |
||||||
|
* valid index has been found. |
||||||
|
*/ |
||||||
|
list_free(indexlist); |
||||||
|
|
||||||
|
/*
|
||||||
|
* The toast relation should have one valid index, so something is going |
||||||
|
* wrong if there is nothing. |
||||||
|
*/ |
||||||
|
if (!found) |
||||||
|
elog(ERROR, "no valid index found for toast relation with Oid %u", |
||||||
|
RelationGetRelid(toastrel)); |
||||||
|
|
||||||
|
return res; |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_close_indexes |
||||||
|
* |
||||||
|
* Close an array of indexes for a toast relation and free it. This should |
||||||
|
* be called for a set of indexes opened previously with toast_open_indexes. |
||||||
|
*/ |
||||||
|
void |
||||||
|
toast_close_indexes(Relation *toastidxs, int num_indexes, LOCKMODE lock) |
||||||
|
{ |
||||||
|
int i; |
||||||
|
|
||||||
|
/* Close relations and clean up things */ |
||||||
|
for (i = 0; i < num_indexes; i++) |
||||||
|
index_close(toastidxs[i], lock); |
||||||
|
pfree(toastidxs); |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* init_toast_snapshot |
||||||
|
* |
||||||
|
* Initialize an appropriate TOAST snapshot. We must use an MVCC snapshot |
||||||
|
* to initialize the TOAST snapshot; since we don't know which one to use, |
||||||
|
* just use the oldest one. This is safe: at worst, we will get a "snapshot |
||||||
|
* too old" error that might have been avoided otherwise. |
||||||
|
*/ |
||||||
|
void |
||||||
|
init_toast_snapshot(Snapshot toast_snapshot) |
||||||
|
{ |
||||||
|
Snapshot snapshot = GetOldestSnapshot(); |
||||||
|
|
||||||
|
if (snapshot == NULL) |
||||||
|
elog(ERROR, "no known snapshots"); |
||||||
|
|
||||||
|
InitToastSnapshot(*toast_snapshot, snapshot->lsn, snapshot->whenTaken); |
||||||
|
} |
||||||
@ -0,0 +1,917 @@ |
|||||||
|
/*-------------------------------------------------------------------------
|
||||||
|
* |
||||||
|
* heaptoast.c |
||||||
|
* Heap-specific definitions for external and compressed storage |
||||||
|
* of variable size attributes. |
||||||
|
* |
||||||
|
* Copyright (c) 2000-2019, PostgreSQL Global Development Group |
||||||
|
* |
||||||
|
* |
||||||
|
* IDENTIFICATION |
||||||
|
* src/backend/access/heap/heaptoast.c |
||||||
|
* |
||||||
|
* |
||||||
|
* INTERFACE ROUTINES |
||||||
|
* toast_insert_or_update - |
||||||
|
* Try to make a given tuple fit into one page by compressing |
||||||
|
* or moving off attributes |
||||||
|
* |
||||||
|
* toast_delete - |
||||||
|
* Reclaim toast storage when a tuple is deleted |
||||||
|
* |
||||||
|
*------------------------------------------------------------------------- |
||||||
|
*/ |
||||||
|
|
||||||
|
#include "postgres.h" |
||||||
|
|
||||||
|
#include "access/detoast.h" |
||||||
|
#include "access/heapam.h" |
||||||
|
#include "access/heaptoast.h" |
||||||
|
#include "access/toast_internals.h" |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_delete - |
||||||
|
* |
||||||
|
* Cascaded delete toast-entries on DELETE |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
void |
||||||
|
toast_delete(Relation rel, HeapTuple oldtup, bool is_speculative) |
||||||
|
{ |
||||||
|
TupleDesc tupleDesc; |
||||||
|
int numAttrs; |
||||||
|
int i; |
||||||
|
Datum toast_values[MaxHeapAttributeNumber]; |
||||||
|
bool toast_isnull[MaxHeapAttributeNumber]; |
||||||
|
|
||||||
|
/*
|
||||||
|
* We should only ever be called for tuples of plain relations or |
||||||
|
* materialized views --- recursing on a toast rel is bad news. |
||||||
|
*/ |
||||||
|
Assert(rel->rd_rel->relkind == RELKIND_RELATION || |
||||||
|
rel->rd_rel->relkind == RELKIND_MATVIEW); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Get the tuple descriptor and break down the tuple into fields. |
||||||
|
* |
||||||
|
* NOTE: it's debatable whether to use heap_deform_tuple() here or just |
||||||
|
* heap_getattr() only the varlena columns. The latter could win if there |
||||||
|
* are few varlena columns and many non-varlena ones. However, |
||||||
|
* heap_deform_tuple costs only O(N) while the heap_getattr way would cost |
||||||
|
* O(N^2) if there are many varlena columns, so it seems better to err on |
||||||
|
* the side of linear cost. (We won't even be here unless there's at |
||||||
|
* least one varlena column, by the way.) |
||||||
|
*/ |
||||||
|
tupleDesc = rel->rd_att; |
||||||
|
numAttrs = tupleDesc->natts; |
||||||
|
|
||||||
|
Assert(numAttrs <= MaxHeapAttributeNumber); |
||||||
|
heap_deform_tuple(oldtup, tupleDesc, toast_values, toast_isnull); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Check for external stored attributes and delete them from the secondary |
||||||
|
* relation. |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
if (TupleDescAttr(tupleDesc, i)->attlen == -1) |
||||||
|
{ |
||||||
|
Datum value = toast_values[i]; |
||||||
|
|
||||||
|
if (toast_isnull[i]) |
||||||
|
continue; |
||||||
|
else if (VARATT_IS_EXTERNAL_ONDISK(PointerGetDatum(value))) |
||||||
|
toast_delete_datum(rel, value, is_speculative); |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_insert_or_update - |
||||||
|
* |
||||||
|
* Delete no-longer-used toast-entries and create new ones to |
||||||
|
* make the new tuple fit on INSERT or UPDATE |
||||||
|
* |
||||||
|
* Inputs: |
||||||
|
* newtup: the candidate new tuple to be inserted |
||||||
|
* oldtup: the old row version for UPDATE, or NULL for INSERT |
||||||
|
* options: options to be passed to heap_insert() for toast rows |
||||||
|
* Result: |
||||||
|
* either newtup if no toasting is needed, or a palloc'd modified tuple |
||||||
|
* that is what should actually get stored |
||||||
|
* |
||||||
|
* NOTE: neither newtup nor oldtup will be modified. This is a change |
||||||
|
* from the pre-8.1 API of this routine. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
HeapTuple |
||||||
|
toast_insert_or_update(Relation rel, HeapTuple newtup, HeapTuple oldtup, |
||||||
|
int options) |
||||||
|
{ |
||||||
|
HeapTuple result_tuple; |
||||||
|
TupleDesc tupleDesc; |
||||||
|
int numAttrs; |
||||||
|
int i; |
||||||
|
|
||||||
|
bool need_change = false; |
||||||
|
bool need_free = false; |
||||||
|
bool need_delold = false; |
||||||
|
bool has_nulls = false; |
||||||
|
|
||||||
|
Size maxDataLen; |
||||||
|
Size hoff; |
||||||
|
|
||||||
|
char toast_action[MaxHeapAttributeNumber]; |
||||||
|
bool toast_isnull[MaxHeapAttributeNumber]; |
||||||
|
bool toast_oldisnull[MaxHeapAttributeNumber]; |
||||||
|
Datum toast_values[MaxHeapAttributeNumber]; |
||||||
|
Datum toast_oldvalues[MaxHeapAttributeNumber]; |
||||||
|
struct varlena *toast_oldexternal[MaxHeapAttributeNumber]; |
||||||
|
int32 toast_sizes[MaxHeapAttributeNumber]; |
||||||
|
bool toast_free[MaxHeapAttributeNumber]; |
||||||
|
bool toast_delold[MaxHeapAttributeNumber]; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Ignore the INSERT_SPECULATIVE option. Speculative insertions/super |
||||||
|
* deletions just normally insert/delete the toast values. It seems |
||||||
|
* easiest to deal with that here, instead on, potentially, multiple |
||||||
|
* callers. |
||||||
|
*/ |
||||||
|
options &= ~HEAP_INSERT_SPECULATIVE; |
||||||
|
|
||||||
|
/*
|
||||||
|
* We should only ever be called for tuples of plain relations or |
||||||
|
* materialized views --- recursing on a toast rel is bad news. |
||||||
|
*/ |
||||||
|
Assert(rel->rd_rel->relkind == RELKIND_RELATION || |
||||||
|
rel->rd_rel->relkind == RELKIND_MATVIEW); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Get the tuple descriptor and break down the tuple(s) into fields. |
||||||
|
*/ |
||||||
|
tupleDesc = rel->rd_att; |
||||||
|
numAttrs = tupleDesc->natts; |
||||||
|
|
||||||
|
Assert(numAttrs <= MaxHeapAttributeNumber); |
||||||
|
heap_deform_tuple(newtup, tupleDesc, toast_values, toast_isnull); |
||||||
|
if (oldtup != NULL) |
||||||
|
heap_deform_tuple(oldtup, tupleDesc, toast_oldvalues, toast_oldisnull); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* Then collect information about the values given |
||||||
|
* |
||||||
|
* NOTE: toast_action[i] can have these values: |
||||||
|
* ' ' default handling |
||||||
|
* 'p' already processed --- don't touch it |
||||||
|
* 'x' incompressible, but OK to move off |
||||||
|
* |
||||||
|
* NOTE: toast_sizes[i] is only made valid for varlena attributes with |
||||||
|
* toast_action[i] different from 'p'. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
memset(toast_action, ' ', numAttrs * sizeof(char)); |
||||||
|
memset(toast_oldexternal, 0, numAttrs * sizeof(struct varlena *)); |
||||||
|
memset(toast_free, 0, numAttrs * sizeof(bool)); |
||||||
|
memset(toast_delold, 0, numAttrs * sizeof(bool)); |
||||||
|
|
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
Form_pg_attribute att = TupleDescAttr(tupleDesc, i); |
||||||
|
struct varlena *old_value; |
||||||
|
struct varlena *new_value; |
||||||
|
|
||||||
|
if (oldtup != NULL) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* For UPDATE get the old and new values of this attribute |
||||||
|
*/ |
||||||
|
old_value = (struct varlena *) DatumGetPointer(toast_oldvalues[i]); |
||||||
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]); |
||||||
|
|
||||||
|
/*
|
||||||
|
* If the old value is stored on disk, check if it has changed so |
||||||
|
* we have to delete it later. |
||||||
|
*/ |
||||||
|
if (att->attlen == -1 && !toast_oldisnull[i] && |
||||||
|
VARATT_IS_EXTERNAL_ONDISK(old_value)) |
||||||
|
{ |
||||||
|
if (toast_isnull[i] || !VARATT_IS_EXTERNAL_ONDISK(new_value) || |
||||||
|
memcmp((char *) old_value, (char *) new_value, |
||||||
|
VARSIZE_EXTERNAL(old_value)) != 0) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* The old external stored value isn't needed any more |
||||||
|
* after the update |
||||||
|
*/ |
||||||
|
toast_delold[i] = true; |
||||||
|
need_delold = true; |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* This attribute isn't changed by this update so we reuse |
||||||
|
* the original reference to the old value in the new |
||||||
|
* tuple. |
||||||
|
*/ |
||||||
|
toast_action[i] = 'p'; |
||||||
|
continue; |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* For INSERT simply get the new value |
||||||
|
*/ |
||||||
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]); |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Handle NULL attributes |
||||||
|
*/ |
||||||
|
if (toast_isnull[i]) |
||||||
|
{ |
||||||
|
toast_action[i] = 'p'; |
||||||
|
has_nulls = true; |
||||||
|
continue; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Now look at varlena attributes |
||||||
|
*/ |
||||||
|
if (att->attlen == -1) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* If the table's attribute says PLAIN always, force it so. |
||||||
|
*/ |
||||||
|
if (att->attstorage == 'p') |
||||||
|
toast_action[i] = 'p'; |
||||||
|
|
||||||
|
/*
|
||||||
|
* We took care of UPDATE above, so any external value we find |
||||||
|
* still in the tuple must be someone else's that we cannot reuse |
||||||
|
* (this includes the case of an out-of-line in-memory datum). |
||||||
|
* Fetch it back (without decompression, unless we are forcing |
||||||
|
* PLAIN storage). If necessary, we'll push it out as a new |
||||||
|
* external value below. |
||||||
|
*/ |
||||||
|
if (VARATT_IS_EXTERNAL(new_value)) |
||||||
|
{ |
||||||
|
toast_oldexternal[i] = new_value; |
||||||
|
if (att->attstorage == 'p') |
||||||
|
new_value = heap_tuple_untoast_attr(new_value); |
||||||
|
else |
||||||
|
new_value = heap_tuple_fetch_attr(new_value); |
||||||
|
toast_values[i] = PointerGetDatum(new_value); |
||||||
|
toast_free[i] = true; |
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Remember the size of this attribute |
||||||
|
*/ |
||||||
|
toast_sizes[i] = VARSIZE_ANY(new_value); |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Not a varlena attribute, plain storage always |
||||||
|
*/ |
||||||
|
toast_action[i] = 'p'; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* Compress and/or save external until data fits into target length |
||||||
|
* |
||||||
|
* 1: Inline compress attributes with attstorage 'x', and store very |
||||||
|
* large attributes with attstorage 'x' or 'e' external immediately |
||||||
|
* 2: Store attributes with attstorage 'x' or 'e' external |
||||||
|
* 3: Inline compress attributes with attstorage 'm' |
||||||
|
* 4: Store attributes with attstorage 'm' external |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
|
||||||
|
/* compute header overhead --- this should match heap_form_tuple() */ |
||||||
|
hoff = SizeofHeapTupleHeader; |
||||||
|
if (has_nulls) |
||||||
|
hoff += BITMAPLEN(numAttrs); |
||||||
|
hoff = MAXALIGN(hoff); |
||||||
|
/* now convert to a limit on the tuple data size */ |
||||||
|
maxDataLen = RelationGetToastTupleTarget(rel, TOAST_TUPLE_TARGET) - hoff; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Look for attributes with attstorage 'x' to compress. Also find large |
||||||
|
* attributes with attstorage 'x' or 'e', and store them external. |
||||||
|
*/ |
||||||
|
while (heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull) > maxDataLen) |
||||||
|
{ |
||||||
|
int biggest_attno = -1; |
||||||
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); |
||||||
|
Datum old_value; |
||||||
|
Datum new_value; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Search for the biggest yet unprocessed internal attribute |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
Form_pg_attribute att = TupleDescAttr(tupleDesc, i); |
||||||
|
|
||||||
|
if (toast_action[i] != ' ') |
||||||
|
continue; |
||||||
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; /* can't happen, toast_action would be 'p' */ |
||||||
|
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; |
||||||
|
if (att->attstorage != 'x' && att->attstorage != 'e') |
||||||
|
continue; |
||||||
|
if (toast_sizes[i] > biggest_size) |
||||||
|
{ |
||||||
|
biggest_attno = i; |
||||||
|
biggest_size = toast_sizes[i]; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
if (biggest_attno < 0) |
||||||
|
break; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Attempt to compress it inline, if it has attstorage 'x' |
||||||
|
*/ |
||||||
|
i = biggest_attno; |
||||||
|
if (TupleDescAttr(tupleDesc, i)->attstorage == 'x') |
||||||
|
{ |
||||||
|
old_value = toast_values[i]; |
||||||
|
new_value = toast_compress_datum(old_value); |
||||||
|
|
||||||
|
if (DatumGetPointer(new_value) != NULL) |
||||||
|
{ |
||||||
|
/* successful compression */ |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(old_value)); |
||||||
|
toast_values[i] = new_value; |
||||||
|
toast_free[i] = true; |
||||||
|
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i])); |
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* incompressible, ignore on subsequent compression passes */ |
||||||
|
toast_action[i] = 'x'; |
||||||
|
} |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* has attstorage 'e', ignore on subsequent compression passes */ |
||||||
|
toast_action[i] = 'x'; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* If this value is by itself more than maxDataLen (after compression |
||||||
|
* if any), push it out to the toast table immediately, if possible. |
||||||
|
* This avoids uselessly compressing other fields in the common case |
||||||
|
* where we have one long field and several short ones. |
||||||
|
* |
||||||
|
* XXX maybe the threshold should be less than maxDataLen? |
||||||
|
*/ |
||||||
|
if (toast_sizes[i] > maxDataLen && |
||||||
|
rel->rd_rel->reltoastrelid != InvalidOid) |
||||||
|
{ |
||||||
|
old_value = toast_values[i]; |
||||||
|
toast_action[i] = 'p'; |
||||||
|
toast_values[i] = toast_save_datum(rel, toast_values[i], |
||||||
|
toast_oldexternal[i], options); |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(old_value)); |
||||||
|
toast_free[i] = true; |
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Second we look for attributes of attstorage 'x' or 'e' that are still |
||||||
|
* inline. But skip this if there's no toast table to push them to. |
||||||
|
*/ |
||||||
|
while (heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull) > maxDataLen && |
||||||
|
rel->rd_rel->reltoastrelid != InvalidOid) |
||||||
|
{ |
||||||
|
int biggest_attno = -1; |
||||||
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); |
||||||
|
Datum old_value; |
||||||
|
|
||||||
|
/*------
|
||||||
|
* Search for the biggest yet inlined attribute with |
||||||
|
* attstorage equals 'x' or 'e' |
||||||
|
*------ |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
Form_pg_attribute att = TupleDescAttr(tupleDesc, i); |
||||||
|
|
||||||
|
if (toast_action[i] == 'p') |
||||||
|
continue; |
||||||
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; /* can't happen, toast_action would be 'p' */ |
||||||
|
if (att->attstorage != 'x' && att->attstorage != 'e') |
||||||
|
continue; |
||||||
|
if (toast_sizes[i] > biggest_size) |
||||||
|
{ |
||||||
|
biggest_attno = i; |
||||||
|
biggest_size = toast_sizes[i]; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
if (biggest_attno < 0) |
||||||
|
break; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Store this external |
||||||
|
*/ |
||||||
|
i = biggest_attno; |
||||||
|
old_value = toast_values[i]; |
||||||
|
toast_action[i] = 'p'; |
||||||
|
toast_values[i] = toast_save_datum(rel, toast_values[i], |
||||||
|
toast_oldexternal[i], options); |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(old_value)); |
||||||
|
toast_free[i] = true; |
||||||
|
|
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Round 3 - this time we take attributes with storage 'm' into |
||||||
|
* compression |
||||||
|
*/ |
||||||
|
while (heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull) > maxDataLen) |
||||||
|
{ |
||||||
|
int biggest_attno = -1; |
||||||
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); |
||||||
|
Datum old_value; |
||||||
|
Datum new_value; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Search for the biggest yet uncompressed internal attribute |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
if (toast_action[i] != ' ') |
||||||
|
continue; |
||||||
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; /* can't happen, toast_action would be 'p' */ |
||||||
|
if (VARATT_IS_COMPRESSED(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; |
||||||
|
if (TupleDescAttr(tupleDesc, i)->attstorage != 'm') |
||||||
|
continue; |
||||||
|
if (toast_sizes[i] > biggest_size) |
||||||
|
{ |
||||||
|
biggest_attno = i; |
||||||
|
biggest_size = toast_sizes[i]; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
if (biggest_attno < 0) |
||||||
|
break; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Attempt to compress it inline |
||||||
|
*/ |
||||||
|
i = biggest_attno; |
||||||
|
old_value = toast_values[i]; |
||||||
|
new_value = toast_compress_datum(old_value); |
||||||
|
|
||||||
|
if (DatumGetPointer(new_value) != NULL) |
||||||
|
{ |
||||||
|
/* successful compression */ |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(old_value)); |
||||||
|
toast_values[i] = new_value; |
||||||
|
toast_free[i] = true; |
||||||
|
toast_sizes[i] = VARSIZE(DatumGetPointer(toast_values[i])); |
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
else |
||||||
|
{ |
||||||
|
/* incompressible, ignore on subsequent compression passes */ |
||||||
|
toast_action[i] = 'x'; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Finally we store attributes of type 'm' externally. At this point we |
||||||
|
* increase the target tuple size, so that 'm' attributes aren't stored |
||||||
|
* externally unless really necessary. |
||||||
|
*/ |
||||||
|
maxDataLen = TOAST_TUPLE_TARGET_MAIN - hoff; |
||||||
|
|
||||||
|
while (heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull) > maxDataLen && |
||||||
|
rel->rd_rel->reltoastrelid != InvalidOid) |
||||||
|
{ |
||||||
|
int biggest_attno = -1; |
||||||
|
int32 biggest_size = MAXALIGN(TOAST_POINTER_SIZE); |
||||||
|
Datum old_value; |
||||||
|
|
||||||
|
/*--------
|
||||||
|
* Search for the biggest yet inlined attribute with |
||||||
|
* attstorage = 'm' |
||||||
|
*-------- |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
if (toast_action[i] == 'p') |
||||||
|
continue; |
||||||
|
if (VARATT_IS_EXTERNAL(DatumGetPointer(toast_values[i]))) |
||||||
|
continue; /* can't happen, toast_action would be 'p' */ |
||||||
|
if (TupleDescAttr(tupleDesc, i)->attstorage != 'm') |
||||||
|
continue; |
||||||
|
if (toast_sizes[i] > biggest_size) |
||||||
|
{ |
||||||
|
biggest_attno = i; |
||||||
|
biggest_size = toast_sizes[i]; |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
if (biggest_attno < 0) |
||||||
|
break; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Store this external |
||||||
|
*/ |
||||||
|
i = biggest_attno; |
||||||
|
old_value = toast_values[i]; |
||||||
|
toast_action[i] = 'p'; |
||||||
|
toast_values[i] = toast_save_datum(rel, toast_values[i], |
||||||
|
toast_oldexternal[i], options); |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(old_value)); |
||||||
|
toast_free[i] = true; |
||||||
|
|
||||||
|
need_change = true; |
||||||
|
need_free = true; |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* In the case we toasted any values, we need to build a new heap tuple |
||||||
|
* with the changed values. |
||||||
|
*/ |
||||||
|
if (need_change) |
||||||
|
{ |
||||||
|
HeapTupleHeader olddata = newtup->t_data; |
||||||
|
HeapTupleHeader new_data; |
||||||
|
int32 new_header_len; |
||||||
|
int32 new_data_len; |
||||||
|
int32 new_tuple_len; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Calculate the new size of the tuple. |
||||||
|
* |
||||||
|
* Note: we used to assume here that the old tuple's t_hoff must equal |
||||||
|
* the new_header_len value, but that was incorrect. The old tuple |
||||||
|
* might have a smaller-than-current natts, if there's been an ALTER |
||||||
|
* TABLE ADD COLUMN since it was stored; and that would lead to a |
||||||
|
* different conclusion about the size of the null bitmap, or even |
||||||
|
* whether there needs to be one at all. |
||||||
|
*/ |
||||||
|
new_header_len = SizeofHeapTupleHeader; |
||||||
|
if (has_nulls) |
||||||
|
new_header_len += BITMAPLEN(numAttrs); |
||||||
|
new_header_len = MAXALIGN(new_header_len); |
||||||
|
new_data_len = heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull); |
||||||
|
new_tuple_len = new_header_len + new_data_len; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Allocate and zero the space needed, and fill HeapTupleData fields. |
||||||
|
*/ |
||||||
|
result_tuple = (HeapTuple) palloc0(HEAPTUPLESIZE + new_tuple_len); |
||||||
|
result_tuple->t_len = new_tuple_len; |
||||||
|
result_tuple->t_self = newtup->t_self; |
||||||
|
result_tuple->t_tableOid = newtup->t_tableOid; |
||||||
|
new_data = (HeapTupleHeader) ((char *) result_tuple + HEAPTUPLESIZE); |
||||||
|
result_tuple->t_data = new_data; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Copy the existing tuple header, but adjust natts and t_hoff. |
||||||
|
*/ |
||||||
|
memcpy(new_data, olddata, SizeofHeapTupleHeader); |
||||||
|
HeapTupleHeaderSetNatts(new_data, numAttrs); |
||||||
|
new_data->t_hoff = new_header_len; |
||||||
|
|
||||||
|
/* Copy over the data, and fill the null bitmap if needed */ |
||||||
|
heap_fill_tuple(tupleDesc, |
||||||
|
toast_values, |
||||||
|
toast_isnull, |
||||||
|
(char *) new_data + new_header_len, |
||||||
|
new_data_len, |
||||||
|
&(new_data->t_infomask), |
||||||
|
has_nulls ? new_data->t_bits : NULL); |
||||||
|
} |
||||||
|
else |
||||||
|
result_tuple = newtup; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free allocated temp values |
||||||
|
*/ |
||||||
|
if (need_free) |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(toast_values[i])); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Delete external values from the old tuple |
||||||
|
*/ |
||||||
|
if (need_delold) |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
if (toast_delold[i]) |
||||||
|
toast_delete_datum(rel, toast_oldvalues[i], false); |
||||||
|
|
||||||
|
return result_tuple; |
||||||
|
} |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_flatten_tuple - |
||||||
|
* |
||||||
|
* "Flatten" a tuple to contain no out-of-line toasted fields. |
||||||
|
* (This does not eliminate compressed or short-header datums.) |
||||||
|
* |
||||||
|
* Note: we expect the caller already checked HeapTupleHasExternal(tup), |
||||||
|
* so there is no need for a short-circuit path. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
HeapTuple |
||||||
|
toast_flatten_tuple(HeapTuple tup, TupleDesc tupleDesc) |
||||||
|
{ |
||||||
|
HeapTuple new_tuple; |
||||||
|
int numAttrs = tupleDesc->natts; |
||||||
|
int i; |
||||||
|
Datum toast_values[MaxTupleAttributeNumber]; |
||||||
|
bool toast_isnull[MaxTupleAttributeNumber]; |
||||||
|
bool toast_free[MaxTupleAttributeNumber]; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Break down the tuple into fields. |
||||||
|
*/ |
||||||
|
Assert(numAttrs <= MaxTupleAttributeNumber); |
||||||
|
heap_deform_tuple(tup, tupleDesc, toast_values, toast_isnull); |
||||||
|
|
||||||
|
memset(toast_free, 0, numAttrs * sizeof(bool)); |
||||||
|
|
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Look at non-null varlena attributes |
||||||
|
*/ |
||||||
|
if (!toast_isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1) |
||||||
|
{ |
||||||
|
struct varlena *new_value; |
||||||
|
|
||||||
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]); |
||||||
|
if (VARATT_IS_EXTERNAL(new_value)) |
||||||
|
{ |
||||||
|
new_value = heap_tuple_fetch_attr(new_value); |
||||||
|
toast_values[i] = PointerGetDatum(new_value); |
||||||
|
toast_free[i] = true; |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Form the reconfigured tuple. |
||||||
|
*/ |
||||||
|
new_tuple = heap_form_tuple(tupleDesc, toast_values, toast_isnull); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Be sure to copy the tuple's identity fields. We also make a point of |
||||||
|
* copying visibility info, just in case anybody looks at those fields in |
||||||
|
* a syscache entry. |
||||||
|
*/ |
||||||
|
new_tuple->t_self = tup->t_self; |
||||||
|
new_tuple->t_tableOid = tup->t_tableOid; |
||||||
|
|
||||||
|
new_tuple->t_data->t_choice = tup->t_data->t_choice; |
||||||
|
new_tuple->t_data->t_ctid = tup->t_data->t_ctid; |
||||||
|
new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK; |
||||||
|
new_tuple->t_data->t_infomask |= |
||||||
|
tup->t_data->t_infomask & HEAP_XACT_MASK; |
||||||
|
new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK; |
||||||
|
new_tuple->t_data->t_infomask2 |= |
||||||
|
tup->t_data->t_infomask2 & HEAP2_XACT_MASK; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free allocated temp values |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(toast_values[i])); |
||||||
|
|
||||||
|
return new_tuple; |
||||||
|
} |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_flatten_tuple_to_datum - |
||||||
|
* |
||||||
|
* "Flatten" a tuple containing out-of-line toasted fields into a Datum. |
||||||
|
* The result is always palloc'd in the current memory context. |
||||||
|
* |
||||||
|
* We have a general rule that Datums of container types (rows, arrays, |
||||||
|
* ranges, etc) must not contain any external TOAST pointers. Without |
||||||
|
* this rule, we'd have to look inside each Datum when preparing a tuple |
||||||
|
* for storage, which would be expensive and would fail to extend cleanly |
||||||
|
* to new sorts of container types. |
||||||
|
* |
||||||
|
* However, we don't want to say that tuples represented as HeapTuples |
||||||
|
* can't contain toasted fields, so instead this routine should be called |
||||||
|
* when such a HeapTuple is being converted into a Datum. |
||||||
|
* |
||||||
|
* While we're at it, we decompress any compressed fields too. This is not |
||||||
|
* necessary for correctness, but reflects an expectation that compression |
||||||
|
* will be more effective if applied to the whole tuple not individual |
||||||
|
* fields. We are not so concerned about that that we want to deconstruct |
||||||
|
* and reconstruct tuples just to get rid of compressed fields, however. |
||||||
|
* So callers typically won't call this unless they see that the tuple has |
||||||
|
* at least one external field. |
||||||
|
* |
||||||
|
* On the other hand, in-line short-header varlena fields are left alone. |
||||||
|
* If we "untoasted" them here, they'd just get changed back to short-header |
||||||
|
* format anyway within heap_fill_tuple. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
Datum |
||||||
|
toast_flatten_tuple_to_datum(HeapTupleHeader tup, |
||||||
|
uint32 tup_len, |
||||||
|
TupleDesc tupleDesc) |
||||||
|
{ |
||||||
|
HeapTupleHeader new_data; |
||||||
|
int32 new_header_len; |
||||||
|
int32 new_data_len; |
||||||
|
int32 new_tuple_len; |
||||||
|
HeapTupleData tmptup; |
||||||
|
int numAttrs = tupleDesc->natts; |
||||||
|
int i; |
||||||
|
bool has_nulls = false; |
||||||
|
Datum toast_values[MaxTupleAttributeNumber]; |
||||||
|
bool toast_isnull[MaxTupleAttributeNumber]; |
||||||
|
bool toast_free[MaxTupleAttributeNumber]; |
||||||
|
|
||||||
|
/* Build a temporary HeapTuple control structure */ |
||||||
|
tmptup.t_len = tup_len; |
||||||
|
ItemPointerSetInvalid(&(tmptup.t_self)); |
||||||
|
tmptup.t_tableOid = InvalidOid; |
||||||
|
tmptup.t_data = tup; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Break down the tuple into fields. |
||||||
|
*/ |
||||||
|
Assert(numAttrs <= MaxTupleAttributeNumber); |
||||||
|
heap_deform_tuple(&tmptup, tupleDesc, toast_values, toast_isnull); |
||||||
|
|
||||||
|
memset(toast_free, 0, numAttrs * sizeof(bool)); |
||||||
|
|
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Look at non-null varlena attributes |
||||||
|
*/ |
||||||
|
if (toast_isnull[i]) |
||||||
|
has_nulls = true; |
||||||
|
else if (TupleDescAttr(tupleDesc, i)->attlen == -1) |
||||||
|
{ |
||||||
|
struct varlena *new_value; |
||||||
|
|
||||||
|
new_value = (struct varlena *) DatumGetPointer(toast_values[i]); |
||||||
|
if (VARATT_IS_EXTERNAL(new_value) || |
||||||
|
VARATT_IS_COMPRESSED(new_value)) |
||||||
|
{ |
||||||
|
new_value = heap_tuple_untoast_attr(new_value); |
||||||
|
toast_values[i] = PointerGetDatum(new_value); |
||||||
|
toast_free[i] = true; |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Calculate the new size of the tuple. |
||||||
|
* |
||||||
|
* This should match the reconstruction code in toast_insert_or_update. |
||||||
|
*/ |
||||||
|
new_header_len = SizeofHeapTupleHeader; |
||||||
|
if (has_nulls) |
||||||
|
new_header_len += BITMAPLEN(numAttrs); |
||||||
|
new_header_len = MAXALIGN(new_header_len); |
||||||
|
new_data_len = heap_compute_data_size(tupleDesc, |
||||||
|
toast_values, toast_isnull); |
||||||
|
new_tuple_len = new_header_len + new_data_len; |
||||||
|
|
||||||
|
new_data = (HeapTupleHeader) palloc0(new_tuple_len); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Copy the existing tuple header, but adjust natts and t_hoff. |
||||||
|
*/ |
||||||
|
memcpy(new_data, tup, SizeofHeapTupleHeader); |
||||||
|
HeapTupleHeaderSetNatts(new_data, numAttrs); |
||||||
|
new_data->t_hoff = new_header_len; |
||||||
|
|
||||||
|
/* Set the composite-Datum header fields correctly */ |
||||||
|
HeapTupleHeaderSetDatumLength(new_data, new_tuple_len); |
||||||
|
HeapTupleHeaderSetTypeId(new_data, tupleDesc->tdtypeid); |
||||||
|
HeapTupleHeaderSetTypMod(new_data, tupleDesc->tdtypmod); |
||||||
|
|
||||||
|
/* Copy over the data, and fill the null bitmap if needed */ |
||||||
|
heap_fill_tuple(tupleDesc, |
||||||
|
toast_values, |
||||||
|
toast_isnull, |
||||||
|
(char *) new_data + new_header_len, |
||||||
|
new_data_len, |
||||||
|
&(new_data->t_infomask), |
||||||
|
has_nulls ? new_data->t_bits : NULL); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free allocated temp values |
||||||
|
*/ |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
if (toast_free[i]) |
||||||
|
pfree(DatumGetPointer(toast_values[i])); |
||||||
|
|
||||||
|
return PointerGetDatum(new_data); |
||||||
|
} |
||||||
|
|
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_build_flattened_tuple - |
||||||
|
* |
||||||
|
* Build a tuple containing no out-of-line toasted fields. |
||||||
|
* (This does not eliminate compressed or short-header datums.) |
||||||
|
* |
||||||
|
* This is essentially just like heap_form_tuple, except that it will |
||||||
|
* expand any external-data pointers beforehand. |
||||||
|
* |
||||||
|
* It's not very clear whether it would be preferable to decompress |
||||||
|
* in-line compressed datums while at it. For now, we don't. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
HeapTuple |
||||||
|
toast_build_flattened_tuple(TupleDesc tupleDesc, |
||||||
|
Datum *values, |
||||||
|
bool *isnull) |
||||||
|
{ |
||||||
|
HeapTuple new_tuple; |
||||||
|
int numAttrs = tupleDesc->natts; |
||||||
|
int num_to_free; |
||||||
|
int i; |
||||||
|
Datum new_values[MaxTupleAttributeNumber]; |
||||||
|
Pointer freeable_values[MaxTupleAttributeNumber]; |
||||||
|
|
||||||
|
/*
|
||||||
|
* We can pass the caller's isnull array directly to heap_form_tuple, but |
||||||
|
* we potentially need to modify the values array. |
||||||
|
*/ |
||||||
|
Assert(numAttrs <= MaxTupleAttributeNumber); |
||||||
|
memcpy(new_values, values, numAttrs * sizeof(Datum)); |
||||||
|
|
||||||
|
num_to_free = 0; |
||||||
|
for (i = 0; i < numAttrs; i++) |
||||||
|
{ |
||||||
|
/*
|
||||||
|
* Look at non-null varlena attributes |
||||||
|
*/ |
||||||
|
if (!isnull[i] && TupleDescAttr(tupleDesc, i)->attlen == -1) |
||||||
|
{ |
||||||
|
struct varlena *new_value; |
||||||
|
|
||||||
|
new_value = (struct varlena *) DatumGetPointer(new_values[i]); |
||||||
|
if (VARATT_IS_EXTERNAL(new_value)) |
||||||
|
{ |
||||||
|
new_value = heap_tuple_fetch_attr(new_value); |
||||||
|
new_values[i] = PointerGetDatum(new_value); |
||||||
|
freeable_values[num_to_free++] = (Pointer) new_value; |
||||||
|
} |
||||||
|
} |
||||||
|
} |
||||||
|
|
||||||
|
/*
|
||||||
|
* Form the reconfigured tuple. |
||||||
|
*/ |
||||||
|
new_tuple = heap_form_tuple(tupleDesc, new_values, isnull); |
||||||
|
|
||||||
|
/*
|
||||||
|
* Free allocated temp values |
||||||
|
*/ |
||||||
|
for (i = 0; i < num_to_free; i++) |
||||||
|
pfree(freeable_values[i]); |
||||||
|
|
||||||
|
return new_tuple; |
||||||
|
} |
||||||
File diff suppressed because it is too large
Load Diff
@ -0,0 +1,92 @@ |
|||||||
|
/*-------------------------------------------------------------------------
|
||||||
|
* |
||||||
|
* detoast.h |
||||||
|
* Access to compressed and external varlena values. |
||||||
|
* |
||||||
|
* Copyright (c) 2000-2019, PostgreSQL Global Development Group |
||||||
|
* |
||||||
|
* src/include/access/detoast.h |
||||||
|
* |
||||||
|
*------------------------------------------------------------------------- |
||||||
|
*/ |
||||||
|
#ifndef DETOAST_H |
||||||
|
#define DETOAST_H |
||||||
|
|
||||||
|
/*
|
||||||
|
* Testing whether an externally-stored value is compressed now requires |
||||||
|
* comparing extsize (the actual length of the external data) to rawsize |
||||||
|
* (the original uncompressed datum's size). The latter includes VARHDRSZ |
||||||
|
* overhead, the former doesn't. We never use compression unless it actually |
||||||
|
* saves space, so we expect either equality or less-than. |
||||||
|
*/ |
||||||
|
#define VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer) \ |
||||||
|
((toast_pointer).va_extsize < (toast_pointer).va_rawsize - VARHDRSZ) |
||||||
|
|
||||||
|
/*
|
||||||
|
* Macro to fetch the possibly-unaligned contents of an EXTERNAL datum |
||||||
|
* into a local "struct varatt_external" toast pointer. This should be |
||||||
|
* just a memcpy, but some versions of gcc seem to produce broken code |
||||||
|
* that assumes the datum contents are aligned. Introducing an explicit |
||||||
|
* intermediate "varattrib_1b_e *" variable seems to fix it. |
||||||
|
*/ |
||||||
|
#define VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr) \ |
||||||
|
do { \
|
||||||
|
varattrib_1b_e *attre = (varattrib_1b_e *) (attr); \
|
||||||
|
Assert(VARATT_IS_EXTERNAL(attre)); \
|
||||||
|
Assert(VARSIZE_EXTERNAL(attre) == sizeof(toast_pointer) + VARHDRSZ_EXTERNAL); \
|
||||||
|
memcpy(&(toast_pointer), VARDATA_EXTERNAL(attre), sizeof(toast_pointer)); \
|
||||||
|
} while (0) |
||||||
|
|
||||||
|
/* Size of an EXTERNAL datum that contains a standard TOAST pointer */ |
||||||
|
#define TOAST_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_external)) |
||||||
|
|
||||||
|
/* Size of an EXTERNAL datum that contains an indirection pointer */ |
||||||
|
#define INDIRECT_POINTER_SIZE (VARHDRSZ_EXTERNAL + sizeof(varatt_indirect)) |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* heap_tuple_fetch_attr() - |
||||||
|
* |
||||||
|
* Fetches an external stored attribute from the toast |
||||||
|
* relation. Does NOT decompress it, if stored external |
||||||
|
* in compressed format. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
extern struct varlena *heap_tuple_fetch_attr(struct varlena *attr); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* heap_tuple_untoast_attr() - |
||||||
|
* |
||||||
|
* Fully detoasts one attribute, fetching and/or decompressing |
||||||
|
* it as needed. |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
extern struct varlena *heap_tuple_untoast_attr(struct varlena *attr); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* heap_tuple_untoast_attr_slice() - |
||||||
|
* |
||||||
|
* Fetches only the specified portion of an attribute. |
||||||
|
* (Handles all cases for attribute storage) |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
extern struct varlena *heap_tuple_untoast_attr_slice(struct varlena *attr, |
||||||
|
int32 sliceoffset, |
||||||
|
int32 slicelength); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_raw_datum_size - |
||||||
|
* |
||||||
|
* Return the raw (detoasted) size of a varlena datum |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
extern Size toast_raw_datum_size(Datum value); |
||||||
|
|
||||||
|
/* ----------
|
||||||
|
* toast_datum_size - |
||||||
|
* |
||||||
|
* Return the storage size of a varlena datum |
||||||
|
* ---------- |
||||||
|
*/ |
||||||
|
extern Size toast_datum_size(Datum value); |
||||||
|
|
||||||
|
#endif /* DETOAST_H */ |
||||||
@ -0,0 +1,54 @@ |
|||||||
|
/*-------------------------------------------------------------------------
|
||||||
|
* |
||||||
|
* toast_internals.h |
||||||
|
* Internal definitions for the TOAST system. |
||||||
|
* |
||||||
|
* Copyright (c) 2000-2019, PostgreSQL Global Development Group |
||||||
|
* |
||||||
|
* src/include/access/toast_internals.h |
||||||
|
* |
||||||
|
*------------------------------------------------------------------------- |
||||||
|
*/ |
||||||
|
#ifndef TOAST_INTERNALS_H |
||||||
|
#define TOAST_INTERNALS_H |
||||||
|
|
||||||
|
#include "storage/lockdefs.h" |
||||||
|
#include "utils/relcache.h" |
||||||
|
#include "utils/snapshot.h" |
||||||
|
|
||||||
|
/*
|
||||||
|
* The information at the start of the compressed toast data. |
||||||
|
*/ |
||||||
|
typedef struct toast_compress_header |
||||||
|
{ |
||||||
|
int32 vl_len_; /* varlena header (do not touch directly!) */ |
||||||
|
int32 rawsize; |
||||||
|
} toast_compress_header; |
||||||
|
|
||||||
|
/*
|
||||||
|
* Utilities for manipulation of header information for compressed |
||||||
|
* toast entries. |
||||||
|
*/ |
||||||
|
#define TOAST_COMPRESS_HDRSZ ((int32) sizeof(toast_compress_header)) |
||||||
|
#define TOAST_COMPRESS_RAWSIZE(ptr) (((toast_compress_header *) (ptr))->rawsize) |
||||||
|
#define TOAST_COMPRESS_RAWDATA(ptr) \ |
||||||
|
(((char *) (ptr)) + TOAST_COMPRESS_HDRSZ) |
||||||
|
#define TOAST_COMPRESS_SET_RAWSIZE(ptr, len) \ |
||||||
|
(((toast_compress_header *) (ptr))->rawsize = (len)) |
||||||
|
|
||||||
|
extern Datum toast_compress_datum(Datum value); |
||||||
|
extern Oid toast_get_valid_index(Oid toastoid, LOCKMODE lock); |
||||||
|
|
||||||
|
extern void toast_delete_datum(Relation rel, Datum value, bool is_speculative); |
||||||
|
extern Datum toast_save_datum(Relation rel, Datum value, |
||||||
|
struct varlena *oldexternal, int options); |
||||||
|
|
||||||
|
extern int toast_open_indexes(Relation toastrel, |
||||||
|
LOCKMODE lock, |
||||||
|
Relation **toastidxs, |
||||||
|
int *num_indexes); |
||||||
|
extern void toast_close_indexes(Relation *toastidxs, int num_indexes, |
||||||
|
LOCKMODE lock); |
||||||
|
extern void init_toast_snapshot(Snapshot toast_snapshot); |
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#endif /* TOAST_INTERNALS_H */ |
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Reference in new issue