mirror of https://github.com/postgres/postgres
The contents of an unlogged table are WAL-logged; thus, they are not available on standby servers and are truncated whenever the database system enters recovery. Indexes on unlogged tables are also unlogged. Unlogged GiST indexes are not currently supported.pull/1/head
Robert Haas
15 years ago
parent
9b8aff8c19
commit
53dbc27c62
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/*-------------------------------------------------------------------------
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* |
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* reinit.c |
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* Reinitialization of unlogged relations |
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* |
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* Portions Copyright (c) 1996-2010, 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/file/reinit.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 <unistd.h> |
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#include "catalog/catalog.h" |
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#include "storage/copydir.h" |
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#include "storage/fd.h" |
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#include "storage/reinit.h" |
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#include "utils/hsearch.h" |
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#include "utils/memutils.h" |
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static void ResetUnloggedRelationsInTablespaceDir(const char *tsdirname, |
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int op); |
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static void ResetUnloggedRelationsInDbspaceDir(const char *dbspacedirname, |
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int op); |
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static bool parse_filename_for_nontemp_relation(const char *name, |
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int *oidchars, ForkNumber *fork); |
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typedef struct { |
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char oid[OIDCHARS+1]; |
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} unlogged_relation_entry; |
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/*
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* Reset unlogged relations from before the last restart. |
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* |
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* If op includes UNLOGGED_RELATION_CLEANUP, we remove all forks of any |
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* relation with an "init" fork, except for the "init" fork itself. |
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* |
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* If op includes UNLOGGED_RELATION_INIT, we copy the "init" fork to the main |
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* fork. |
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*/ |
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void |
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ResetUnloggedRelations(int op) |
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{ |
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char temp_path[MAXPGPATH]; |
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DIR *spc_dir; |
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struct dirent *spc_de; |
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MemoryContext tmpctx, oldctx; |
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/* Log it. */ |
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ereport(DEBUG1, |
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(errmsg("resetting unlogged relations: cleanup %d init %d", |
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(op & UNLOGGED_RELATION_CLEANUP) != 0, |
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(op & UNLOGGED_RELATION_INIT) != 0))); |
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/*
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* Just to be sure we don't leak any memory, let's create a temporary |
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* memory context for this operation. |
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*/ |
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tmpctx = AllocSetContextCreate(CurrentMemoryContext, |
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"ResetUnloggedRelations", |
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ALLOCSET_DEFAULT_MINSIZE, |
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ALLOCSET_DEFAULT_INITSIZE, |
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ALLOCSET_DEFAULT_MAXSIZE); |
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oldctx = MemoryContextSwitchTo(tmpctx); |
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/*
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* First process unlogged files in pg_default ($PGDATA/base) |
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*/ |
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ResetUnloggedRelationsInTablespaceDir("base", op); |
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/*
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* Cycle through directories for all non-default tablespaces. |
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*/ |
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spc_dir = AllocateDir("pg_tblspc"); |
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while ((spc_de = ReadDir(spc_dir, "pg_tblspc")) != NULL) |
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{ |
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if (strcmp(spc_de->d_name, ".") == 0 || |
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strcmp(spc_de->d_name, "..") == 0) |
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continue; |
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snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s", |
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spc_de->d_name, TABLESPACE_VERSION_DIRECTORY); |
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ResetUnloggedRelationsInTablespaceDir(temp_path, op); |
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} |
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FreeDir(spc_dir); |
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/*
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* Restore memory context. |
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*/ |
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MemoryContextSwitchTo(oldctx); |
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MemoryContextDelete(tmpctx); |
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} |
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/* Process one tablespace directory for ResetUnloggedRelations */ |
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static void |
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ResetUnloggedRelationsInTablespaceDir(const char *tsdirname, int op) |
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{ |
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DIR *ts_dir; |
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struct dirent *de; |
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char dbspace_path[MAXPGPATH]; |
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ts_dir = AllocateDir(tsdirname); |
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if (ts_dir == NULL) |
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{ |
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/* anything except ENOENT is fishy */ |
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if (errno != ENOENT) |
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elog(LOG, |
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"could not open tablespace directory \"%s\": %m", |
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tsdirname); |
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return; |
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} |
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while ((de = ReadDir(ts_dir, tsdirname)) != NULL) |
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{ |
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int i = 0; |
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/*
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* We're only interested in the per-database directories, which have |
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* numeric names. Note that this code will also (properly) ignore "." |
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* and "..". |
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*/ |
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while (isdigit((unsigned char) de->d_name[i])) |
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++i; |
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if (de->d_name[i] != '\0' || i == 0) |
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continue; |
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snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s", |
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tsdirname, de->d_name); |
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ResetUnloggedRelationsInDbspaceDir(dbspace_path, op); |
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} |
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FreeDir(ts_dir); |
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} |
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/* Process one per-dbspace directory for ResetUnloggedRelations */ |
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static void |
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ResetUnloggedRelationsInDbspaceDir(const char *dbspacedirname, int op) |
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{ |
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DIR *dbspace_dir; |
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struct dirent *de; |
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char rm_path[MAXPGPATH]; |
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/* Caller must specify at least one operation. */ |
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Assert((op & (UNLOGGED_RELATION_CLEANUP | UNLOGGED_RELATION_INIT)) != 0); |
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/*
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* Cleanup is a two-pass operation. First, we go through and identify all |
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* the files with init forks. Then, we go through again and nuke |
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* everything with the same OID except the init fork. |
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*/ |
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if ((op & UNLOGGED_RELATION_CLEANUP) != 0) |
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{ |
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HTAB *hash = NULL; |
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HASHCTL ctl; |
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/* Open the directory. */ |
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dbspace_dir = AllocateDir(dbspacedirname); |
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if (dbspace_dir == NULL) |
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{ |
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elog(LOG, |
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"could not open dbspace directory \"%s\": %m", |
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dbspacedirname); |
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return; |
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} |
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/*
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* It's possible that someone could create a ton of unlogged relations |
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* in the same database & tablespace, so we'd better use a hash table |
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* rather than an array or linked list to keep track of which files |
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* need to be reset. Otherwise, this cleanup operation would be |
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* O(n^2). |
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*/ |
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ctl.keysize = sizeof(unlogged_relation_entry); |
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ctl.entrysize = sizeof(unlogged_relation_entry); |
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hash = hash_create("unlogged hash", 32, &ctl, HASH_ELEM); |
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/* Scan the directory. */ |
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while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL) |
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{ |
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ForkNumber forkNum; |
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int oidchars; |
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unlogged_relation_entry ent; |
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/* Skip anything that doesn't look like a relation data file. */ |
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if (!parse_filename_for_nontemp_relation(de->d_name, &oidchars, |
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&forkNum)) |
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continue; |
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/* Also skip it unless this is the init fork. */ |
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if (forkNum != INIT_FORKNUM) |
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continue; |
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/*
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* Put the OID portion of the name into the hash table, if it isn't |
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* already. |
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*/ |
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memset(ent.oid, 0, sizeof(ent.oid)); |
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memcpy(ent.oid, de->d_name, oidchars); |
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hash_search(hash, &ent, HASH_ENTER, NULL); |
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} |
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/* Done with the first pass. */ |
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FreeDir(dbspace_dir); |
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/*
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* If we didn't find any init forks, there's no point in continuing; |
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* we can bail out now. |
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*/ |
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if (hash_get_num_entries(hash) == 0) |
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{ |
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hash_destroy(hash); |
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return; |
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} |
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/*
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* Now, make a second pass and remove anything that matches. First, |
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* reopen the directory. |
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*/ |
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dbspace_dir = AllocateDir(dbspacedirname); |
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if (dbspace_dir == NULL) |
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{ |
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elog(LOG, |
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"could not open dbspace directory \"%s\": %m", |
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dbspacedirname); |
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hash_destroy(hash); |
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return; |
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} |
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/* Scan the directory. */ |
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while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL) |
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{ |
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ForkNumber forkNum; |
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int oidchars; |
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bool found; |
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unlogged_relation_entry ent; |
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/* Skip anything that doesn't look like a relation data file. */ |
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if (!parse_filename_for_nontemp_relation(de->d_name, &oidchars, |
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&forkNum)) |
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continue; |
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/* We never remove the init fork. */ |
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if (forkNum == INIT_FORKNUM) |
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continue; |
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/*
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* See whether the OID portion of the name shows up in the hash |
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* table. |
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*/ |
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memset(ent.oid, 0, sizeof(ent.oid)); |
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memcpy(ent.oid, de->d_name, oidchars); |
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hash_search(hash, &ent, HASH_FIND, &found); |
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/* If so, nuke it! */ |
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if (found) |
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{ |
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snprintf(rm_path, sizeof(rm_path), "%s/%s", |
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dbspacedirname, de->d_name); |
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/*
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* It's tempting to actually throw an error here, but since |
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* this code gets run during database startup, that could |
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* result in the database failing to start. (XXX Should we do |
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* it anyway?) |
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*/ |
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if (unlink(rm_path)) |
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elog(LOG, "could not unlink file \"%s\": %m", rm_path); |
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else |
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elog(DEBUG2, "unlinked file \"%s\"", rm_path); |
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} |
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} |
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/* Cleanup is complete. */ |
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FreeDir(dbspace_dir); |
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hash_destroy(hash); |
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} |
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/*
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* Initialization happens after cleanup is complete: we copy each init |
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* fork file to the corresponding main fork file. Note that if we are |
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* asked to do both cleanup and init, we may never get here: if the cleanup |
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* code determines that there are no init forks in this dbspace, it will |
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* return before we get to this point. |
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*/ |
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if ((op & UNLOGGED_RELATION_INIT) != 0) |
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{ |
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/* Open the directory. */ |
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dbspace_dir = AllocateDir(dbspacedirname); |
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if (dbspace_dir == NULL) |
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{ |
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/* we just saw this directory, so it really ought to be there */ |
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elog(LOG, |
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"could not open dbspace directory \"%s\": %m", |
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dbspacedirname); |
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return; |
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} |
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/* Scan the directory. */ |
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while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL) |
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{ |
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ForkNumber forkNum; |
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int oidchars; |
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char oidbuf[OIDCHARS+1]; |
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char srcpath[MAXPGPATH]; |
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char dstpath[MAXPGPATH]; |
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/* Skip anything that doesn't look like a relation data file. */ |
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if (!parse_filename_for_nontemp_relation(de->d_name, &oidchars, |
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&forkNum)) |
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continue; |
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/* Also skip it unless this is the init fork. */ |
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if (forkNum != INIT_FORKNUM) |
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continue; |
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/* Construct source pathname. */ |
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snprintf(srcpath, sizeof(srcpath), "%s/%s", |
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dbspacedirname, de->d_name); |
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/* Construct destination pathname. */ |
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memcpy(oidbuf, de->d_name, oidchars); |
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oidbuf[oidchars] = '\0'; |
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snprintf(dstpath, sizeof(dstpath), "%s/%s%s", |
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dbspacedirname, oidbuf, de->d_name + oidchars + 1 + |
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strlen(forkNames[INIT_FORKNUM])); |
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/* OK, we're ready to perform the actual copy. */ |
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elog(DEBUG2, "copying %s to %s", srcpath, dstpath); |
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copy_file(srcpath, dstpath); |
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} |
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/* Done with the first pass. */ |
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FreeDir(dbspace_dir); |
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} |
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} |
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/*
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* Basic parsing of putative relation filenames. |
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* |
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* This funtion returns true if the file appears to be in the correct format |
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* for a non-temporary relation and false otherwise. |
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* |
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* NB: If this function returns true, the caller is entitled to assume that |
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* *oidchars has been set to the a value no more than OIDCHARS, and thus |
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* that a buffer of OIDCHARS+1 characters is sufficient to hold the OID |
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* portion of the filename. This is critical to protect against a possible |
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* buffer overrun. |
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*/ |
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static bool |
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parse_filename_for_nontemp_relation(const char *name, int *oidchars, |
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ForkNumber *fork) |
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{ |
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int pos; |
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/* Look for a non-empty string of digits (that isn't too long). */ |
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for (pos = 0; isdigit((unsigned char) name[pos]); ++pos) |
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; |
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if (pos == 0 || pos > OIDCHARS) |
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return false; |
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*oidchars = pos; |
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/* Check for a fork name. */ |
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if (name[pos] != '_') |
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*fork = MAIN_FORKNUM; |
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else |
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{ |
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int forkchar; |
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forkchar = forkname_chars(&name[pos+1], fork); |
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if (forkchar <= 0) |
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return false; |
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pos += forkchar + 1; |
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} |
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/* Check for a segment number. */ |
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if (name[pos] == '.') |
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{ |
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int segchar; |
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for (segchar = 1; isdigit((unsigned char) name[pos+segchar]); ++segchar) |
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; |
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if (segchar <= 1) |
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return false; |
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pos += segchar; |
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} |
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/* Now we should be at the end. */ |
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if (name[pos] != '\0') |
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return false; |
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return true; |
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} |
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@ -0,0 +1,23 @@ |
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/*-------------------------------------------------------------------------
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* |
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* reinit.h |
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* Reinitialization of unlogged relations |
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* |
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* |
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* Portions Copyright (c) 1996-2010, 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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* src/include/storage/fd.h |
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* |
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*------------------------------------------------------------------------- |
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*/ |
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#ifndef REINIT_H |
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#define REINIT_H |
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extern void ResetUnloggedRelations(int op); |
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#define UNLOGGED_RELATION_CLEANUP 0x0001 |
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#define UNLOGGED_RELATION_INIT 0x0002 |
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#endif /* REINIT_H */ |
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