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Move relpath() to libpgcommon
This enables non-backend code, such as pg_xlogdump, to use it easily. The previous location, in src/backend/catalog/catalog.c, made that essentially impossible because that file depends on many backend-only facilities; so this needs to live separately.
This commit is contained in:
Alvaro Herrera
162
src/common/relpath.c
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162
src/common/relpath.c
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/*-------------------------------------------------------------------------
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* relpath.c
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* Shared frontend/backend code to find out pathnames of relation files
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*
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* Portions Copyright (c) 1996-2013, 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/common/relpath.c
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef FRONTEND
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#include "postgres.h"
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#else
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#include "postgres_fe.h"
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#endif
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#include "catalog/pg_tablespace.h"
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#include "common/relpath.h"
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#include "storage/backendid.h"
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#define FORKNAMECHARS 4 /* max chars for a fork name */
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/*
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* Lookup table of fork name by fork number.
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*
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* If you add a new entry, remember to update the errhint below, and the
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* documentation for pg_relation_size(). Also keep FORKNAMECHARS above
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* up-to-date.
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*/
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const char *forkNames[] = {
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"main", /* MAIN_FORKNUM */
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"fsm", /* FSM_FORKNUM */
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"vm", /* VISIBILITYMAP_FORKNUM */
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"init" /* INIT_FORKNUM */
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};
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/*
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* forkname_chars
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* We use this to figure out whether a filename could be a relation
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* fork (as opposed to an oddly named stray file that somehow ended
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* up in the database directory). If the passed string begins with
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* a fork name (other than the main fork name), we return its length,
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* and set *fork (if not NULL) to the fork number. If not, we return 0.
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*
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* Note that the present coding assumes that there are no fork names which
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* are prefixes of other fork names.
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*/
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int
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forkname_chars(const char *str, ForkNumber *fork)
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{
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ForkNumber forkNum;
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for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
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{
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int len = strlen(forkNames[forkNum]);
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if (strncmp(forkNames[forkNum], str, len) == 0)
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{
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if (fork)
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*fork = forkNum;
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return len;
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}
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}
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return 0;
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}
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/*
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* relpathbackend - construct path to a relation's file
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*
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* Result is a palloc'd string.
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*/
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char *
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relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
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{
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int pathlen;
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char *path;
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if (rnode.spcNode == GLOBALTABLESPACE_OID)
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{
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/* Shared system relations live in {datadir}/global */
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Assert(rnode.dbNode == 0);
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Assert(backend == InvalidBackendId);
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pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
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path = (char *) palloc(pathlen);
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if (forknum != MAIN_FORKNUM)
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snprintf(path, pathlen, "global/%u_%s",
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rnode.relNode, forkNames[forknum]);
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else
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snprintf(path, pathlen, "global/%u", rnode.relNode);
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}
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else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
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{
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/* The default tablespace is {datadir}/base */
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if (backend == InvalidBackendId)
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{
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pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
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path = (char *) palloc(pathlen);
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if (forknum != MAIN_FORKNUM)
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snprintf(path, pathlen, "base/%u/%u_%s",
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rnode.dbNode, rnode.relNode,
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forkNames[forknum]);
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else
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snprintf(path, pathlen, "base/%u/%u",
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rnode.dbNode, rnode.relNode);
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}
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else
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{
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/* OIDCHARS will suffice for an integer, too */
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pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
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+ FORKNAMECHARS + 1;
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path = (char *) palloc(pathlen);
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if (forknum != MAIN_FORKNUM)
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snprintf(path, pathlen, "base/%u/t%d_%u_%s",
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rnode.dbNode, backend, rnode.relNode,
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forkNames[forknum]);
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else
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snprintf(path, pathlen, "base/%u/t%d_%u",
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rnode.dbNode, backend, rnode.relNode);
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}
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}
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else
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{
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/* All other tablespaces are accessed via symlinks */
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if (backend == InvalidBackendId)
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{
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pathlen = 9 + 1 + OIDCHARS + 1
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+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
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+ OIDCHARS + 1 + FORKNAMECHARS + 1;
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path = (char *) palloc(pathlen);
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if (forknum != MAIN_FORKNUM)
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snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
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rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
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rnode.dbNode, rnode.relNode,
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forkNames[forknum]);
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else
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snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
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rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
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rnode.dbNode, rnode.relNode);
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}
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else
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{
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/* OIDCHARS will suffice for an integer, too */
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pathlen = 9 + 1 + OIDCHARS + 1
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+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
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+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
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path = (char *) palloc(pathlen);
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if (forknum != MAIN_FORKNUM)
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snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
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rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
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rnode.dbNode, backend, rnode.relNode,
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forkNames[forknum]);
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else
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snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
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rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
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rnode.dbNode, backend, rnode.relNode);
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}
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}
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return path;
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}
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