mirror of https://github.com/postgres/postgres
The new view lists all IO handles that are currently in use and is mainly useful for PG developers, but may also be useful when tuning PG. Bumps catversion. Reviewed-by: Noah Misch <noah@leadboat.com> Discussion: https://postgr.es/m/uvrtrknj4kdytuboidbhwclo4gxhswwcpgadptsjvjqcluzmah%40brqs62irg4dtpull/208/head
Andres Freund
3 months ago
parent
46250cdcb0
commit
60f566b4f2
@ -0,0 +1,230 @@ |
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/*-------------------------------------------------------------------------
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* |
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* aio_funcs.c |
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* AIO - SQL interface for AIO |
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* |
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* |
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* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group |
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* Portions Copyright (c) 1994, Regents of the University of California |
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* |
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* IDENTIFICATION |
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* src/backend/storage/aio/aio_funcs.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 "fmgr.h" |
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#include "funcapi.h" |
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#include "nodes/execnodes.h" |
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#include "port/atomics.h" |
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#include "storage/aio_internal.h" |
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#include "storage/lock.h" |
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#include "storage/proc.h" |
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#include "storage/procnumber.h" |
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#include "utils/builtins.h" |
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#include "utils/fmgrprotos.h" |
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#include "utils/tuplestore.h" |
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/*
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* Byte length of an iovec. |
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*/ |
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static size_t |
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iov_byte_length(const struct iovec *iov, int cnt) |
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{ |
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size_t len = 0; |
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for (int i = 0; i < cnt; i++) |
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{ |
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len += iov[i].iov_len; |
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} |
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return len; |
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} |
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Datum |
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pg_get_aios(PG_FUNCTION_ARGS) |
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{ |
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ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo; |
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InitMaterializedSRF(fcinfo, 0); |
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#define PG_GET_AIOS_COLS 15 |
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for (uint64 i = 0; i < pgaio_ctl->io_handle_count; i++) |
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{ |
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PgAioHandle *live_ioh = &pgaio_ctl->io_handles[i]; |
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uint32 ioh_id = pgaio_io_get_id(live_ioh); |
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Datum values[PG_GET_AIOS_COLS] = {0}; |
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bool nulls[PG_GET_AIOS_COLS] = {0}; |
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ProcNumber owner; |
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PGPROC *owner_proc; |
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int32 owner_pid; |
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PgAioHandleState start_state; |
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uint64 start_generation; |
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PgAioHandle ioh_copy; |
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struct iovec iov_copy[PG_IOV_MAX]; |
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/*
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* There is no lock that could prevent the state of the IO to advance |
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* concurrently - and we don't want to introduce one, as that would |
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* introduce atomics into a very common path. Instead we |
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* |
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* 1) Determine the state + generation of the IO. |
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* |
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* 2) Copy the IO to local memory. |
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* |
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* 3) Check if state or generation of the IO changed. If the state |
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* changed, retry, if the generation changed don't display the IO. |
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*/ |
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/* 1) from above */ |
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start_generation = live_ioh->generation; |
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/*
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* Retry at this point, so we can accept changing states, but not |
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* changing generations. |
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*/ |
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retry: |
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pg_read_barrier(); |
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start_state = live_ioh->state; |
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if (start_state == PGAIO_HS_IDLE) |
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continue; |
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/* 2) from above */ |
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memcpy(&ioh_copy, live_ioh, sizeof(PgAioHandle)); |
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/*
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* Safe to copy even if no iovec is used - we always reserve the |
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* required space. |
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*/ |
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memcpy(&iov_copy, &pgaio_ctl->iovecs[ioh_copy.iovec_off], |
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PG_IOV_MAX * sizeof(struct iovec)); |
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/*
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* Copy information about owner before 3) below, if the process exited |
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* it'd have to wait for the IO to finish first, which we would detect |
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* in 3). |
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*/ |
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owner = ioh_copy.owner_procno; |
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owner_proc = GetPGProcByNumber(owner); |
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owner_pid = owner_proc->pid; |
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/* 3) from above */ |
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pg_read_barrier(); |
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/*
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* The IO completed and a new one was started with the same ID. Don't |
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* display it - it really started after this function was called. |
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* There be a risk of a livelock if we just retried endlessly, if IOs |
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* complete very quickly. |
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*/ |
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if (live_ioh->generation != start_generation) |
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continue; |
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/*
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* The IO's state changed while we were "rendering" it. Just start |
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* from scratch. There's no risk of a livelock here, as an IO has a |
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* limited sets of states it can be in, and state changes go only in a |
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* single direction. |
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*/ |
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if (live_ioh->state != start_state) |
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goto retry; |
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/*
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* Now that we have copied the IO into local memory and checked that |
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* it's still in the same state, we are not allowed to access "live" |
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* memory anymore. To make it slightly easier to catch such cases, set |
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* the "live" pointers to NULL. |
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*/ |
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live_ioh = NULL; |
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owner_proc = NULL; |
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/* column: owning pid */ |
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if (owner_pid != 0) |
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values[0] = Int32GetDatum(owner_pid); |
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else |
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nulls[0] = false; |
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/* column: IO's id */ |
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values[1] = ioh_id; |
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/* column: IO's generation */ |
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values[2] = Int64GetDatum(start_generation); |
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/* column: IO's state */ |
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values[3] = CStringGetTextDatum(pgaio_io_get_state_name(&ioh_copy)); |
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/*
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* If the IO is in PGAIO_HS_HANDED_OUT state, none of the following |
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* fields are valid yet (or are in the process of being set). |
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* Therefore we don't want to display any other columns. |
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*/ |
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if (start_state == PGAIO_HS_HANDED_OUT) |
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{ |
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memset(nulls + 4, 1, (lengthof(nulls) - 4) * sizeof(bool)); |
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goto display; |
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} |
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/* column: IO's operation */ |
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values[4] = CStringGetTextDatum(pgaio_io_get_op_name(&ioh_copy)); |
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/* columns: details about the IO's operation (offset, length) */ |
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switch (ioh_copy.op) |
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{ |
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case PGAIO_OP_INVALID: |
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nulls[5] = true; |
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nulls[6] = true; |
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break; |
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case PGAIO_OP_READV: |
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values[5] = Int64GetDatum(ioh_copy.op_data.read.offset); |
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values[6] = |
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Int64GetDatum(iov_byte_length(iov_copy, ioh_copy.op_data.read.iov_length)); |
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break; |
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case PGAIO_OP_WRITEV: |
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values[5] = Int64GetDatum(ioh_copy.op_data.write.offset); |
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values[6] = |
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Int64GetDatum(iov_byte_length(iov_copy, ioh_copy.op_data.write.iov_length)); |
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break; |
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} |
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/* column: IO's target */ |
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values[7] = CStringGetTextDatum(pgaio_io_get_target_name(&ioh_copy)); |
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/* column: length of IO's data array */ |
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values[8] = Int16GetDatum(ioh_copy.handle_data_len); |
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/* column: raw result (i.e. some form of syscall return value) */ |
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if (start_state == PGAIO_HS_COMPLETED_IO |
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|| start_state == PGAIO_HS_COMPLETED_SHARED |
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|| start_state == PGAIO_HS_COMPLETED_LOCAL) |
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values[9] = Int32GetDatum(ioh_copy.result); |
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else |
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nulls[9] = true; |
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/*
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* column: result in the higher level representation (unknown if not |
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* finished) |
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*/ |
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values[10] = |
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CStringGetTextDatum(pgaio_result_status_string(ioh_copy.distilled_result.status)); |
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/* column: target description */ |
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values[11] = CStringGetTextDatum(pgaio_io_get_target_description(&ioh_copy)); |
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/* columns: one for each flag */ |
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values[12] = BoolGetDatum(ioh_copy.flags & PGAIO_HF_SYNCHRONOUS); |
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values[13] = BoolGetDatum(ioh_copy.flags & PGAIO_HF_REFERENCES_LOCAL); |
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values[14] = BoolGetDatum(ioh_copy.flags & PGAIO_HF_BUFFERED); |
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display: |
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tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls); |
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} |
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return (Datum) 0; |
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} |
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