From b3e23e59ff74f9def70416a65a4ebb59052c49bf Mon Sep 17 00:00:00 2001 From: Manni Wood Date: Fri, 7 Nov 2025 15:12:18 -0600 Subject: [PATCH v9 1/2] Supporting changes for pg_get_tablespace_ddl function MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Moving core logic of pg_tablespace_location() to new generic function get_tablespace_loc_string() Authors: Manni Wood and Nishant Sharma Reviewers: Vaibhav Dalvi, Ian Barwick, Jim Jones, Álvaro Herrera Discussion: https://www.postgresql.org/message-id/flat/CAKWEB6rmnmGKUA87Zmq-s=b3Scsnj02C0kObQjnbL2ajfPWGEw@mail.gmail.com --- src/backend/catalog/Makefile | 1 + src/backend/catalog/pg_tablespace.c | 151 ++++++++++++++++++++++++++++ src/backend/utils/adt/misc.c | 62 +----------- src/backend/utils/adt/ruleutils.c | 1 + src/include/catalog/pg_tablespace.h | 2 + 5 files changed, 159 insertions(+), 58 deletions(-) create mode 100644 src/backend/catalog/pg_tablespace.c diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile index c090094ed08..8e40e1b8189 100644 --- a/src/backend/catalog/Makefile +++ b/src/backend/catalog/Makefile @@ -44,6 +44,7 @@ OBJS = \ pg_range.o \ pg_shdepend.o \ pg_subscription.o \ + pg_tablespace.o \ pg_type.o \ storage.o \ toasting.o diff --git a/src/backend/catalog/pg_tablespace.c b/src/backend/catalog/pg_tablespace.c new file mode 100644 index 00000000000..95f7c3bf6d0 --- /dev/null +++ b/src/backend/catalog/pg_tablespace.c @@ -0,0 +1,151 @@ +/*------------------------------------------------------------------------- + * + * pg_tablespace.c + * routines to support tablespaces + * + * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * + * IDENTIFICATION + * src/backend/catalog/pg_tablespace.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include +#include +#include +#include + +#include "access/amapi.h" +#include "access/htup_details.h" +#include "access/relation.h" +#include "access/table.h" +#include "catalog/pg_aggregate.h" +#include "catalog/pg_am.h" +#include "catalog/pg_authid.h" +#include "catalog/pg_collation.h" +#include "catalog/pg_constraint.h" +#include "catalog/pg_depend.h" +#include "catalog/pg_language.h" +#include "catalog/pg_opclass.h" +#include "catalog/pg_operator.h" +#include "catalog/pg_partitioned_table.h" +#include "catalog/pg_proc.h" +#include "catalog/pg_statistic_ext.h" +#include "catalog/pg_tablespace.h" +#include "catalog/pg_trigger.h" +#include "catalog/pg_type.h" +#include "commands/defrem.h" +#include "commands/tablespace.h" +#include "common/keywords.h" +#include "executor/spi.h" +#include "funcapi.h" +#include "mb/pg_wchar.h" +#include "miscadmin.h" +#include "nodes/makefuncs.h" +#include "nodes/nodeFuncs.h" +#include "nodes/pathnodes.h" +#include "optimizer/optimizer.h" +#include "parser/parse_agg.h" +#include "parser/parse_func.h" +#include "parser/parse_oper.h" +#include "parser/parse_relation.h" +#include "parser/parser.h" +#include "parser/parsetree.h" +#include "rewrite/rewriteHandler.h" +#include "rewrite/rewriteManip.h" +#include "rewrite/rewriteSupport.h" +#include "utils/array.h" +#include "utils/builtins.h" +#include "utils/fmgroids.h" +#include "utils/guc.h" +#include "utils/hsearch.h" +#include "utils/lsyscache.h" +#include "utils/partcache.h" +#include "utils/rel.h" +#include "utils/ruleutils.h" +#include "utils/snapmgr.h" +#include "utils/syscache.h" +#include "utils/typcache.h" +#include "utils/varlena.h" +#include "utils/xml.h" + +/* + * get_tablespace_loc_string - Get a tablespace's location as a C-string. + */ +char * +get_tablespace_loc_string(Oid tablespaceOid) +{ + char sourcepath[MAXPGPATH] = {'\0'}; + char targetpath[MAXPGPATH] = {'\0'}; + int rllen; + struct stat st; + StringInfoData buf; + + initStringInfo(&buf); + appendStringInfoString(&buf, ""); + + /* + * It's useful to apply this function to pg_class.reltablespace, wherein + * zero means "the database's default tablespace". So, rather than + * throwing an error for zero, we choose to assume that's what is meant. + */ + if (tablespaceOid == InvalidOid) + tablespaceOid = MyDatabaseTableSpace; + + /* + * Return empty string for the cluster's default tablespaces + */ + if (tablespaceOid == DEFAULTTABLESPACE_OID || + tablespaceOid == GLOBALTABLESPACE_OID) + return buf.data; + + /* + * Find the location of the tablespace by reading the symbolic link that + * is in pg_tblspc/. + */ + snprintf(sourcepath, sizeof(sourcepath), "%s/%u", PG_TBLSPC_DIR, tablespaceOid); + + /* + * Before reading the link, check if the source path is a link or a + * junction point. Note that a directory is possible for a tablespace + * created with allow_in_place_tablespaces enabled. If a directory is + * found, a relative path to the data directory is returned. + */ + if (lstat(sourcepath, &st) < 0) + { + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not stat file \"%s\": %m", + sourcepath))); + } + + if (!S_ISLNK(st.st_mode)) + { + appendStringInfoString(&buf, sourcepath); + return buf.data; + } + + /* + * In presence of a link or a junction point, return the path pointing to. + */ + rllen = readlink(sourcepath, targetpath, sizeof(targetpath)); + if (rllen < 0) + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not read symbolic link \"%s\": %m", + sourcepath))); + if (rllen >= sizeof(targetpath)) + ereport(ERROR, + (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), + errmsg("symbolic link \"%s\" target is too long", + sourcepath))); + targetpath[rllen] = '\0'; + + appendStringInfoString(&buf, targetpath); + + return buf.data; +} diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c index fa1cb675027..cb99d7435eb 100644 --- a/src/backend/utils/adt/misc.c +++ b/src/backend/utils/adt/misc.c @@ -315,66 +315,12 @@ Datum pg_tablespace_location(PG_FUNCTION_ARGS) { Oid tablespaceOid = PG_GETARG_OID(0); - char sourcepath[MAXPGPATH]; - char targetpath[MAXPGPATH]; - int rllen; - struct stat st; + char *tablespaceLoc; - /* - * It's useful to apply this function to pg_class.reltablespace, wherein - * zero means "the database's default tablespace". So, rather than - * throwing an error for zero, we choose to assume that's what is meant. - */ - if (tablespaceOid == InvalidOid) - tablespaceOid = MyDatabaseTableSpace; - - /* - * Return empty string for the cluster's default tablespaces - */ - if (tablespaceOid == DEFAULTTABLESPACE_OID || - tablespaceOid == GLOBALTABLESPACE_OID) - PG_RETURN_TEXT_P(cstring_to_text("")); - - /* - * Find the location of the tablespace by reading the symbolic link that - * is in pg_tblspc/. - */ - snprintf(sourcepath, sizeof(sourcepath), "%s/%u", PG_TBLSPC_DIR, tablespaceOid); - - /* - * Before reading the link, check if the source path is a link or a - * junction point. Note that a directory is possible for a tablespace - * created with allow_in_place_tablespaces enabled. If a directory is - * found, a relative path to the data directory is returned. - */ - if (lstat(sourcepath, &st) < 0) - { - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not stat file \"%s\": %m", - sourcepath))); - } - - if (!S_ISLNK(st.st_mode)) - PG_RETURN_TEXT_P(cstring_to_text(sourcepath)); - - /* - * In presence of a link or a junction point, return the path pointing to. - */ - rllen = readlink(sourcepath, targetpath, sizeof(targetpath)); - if (rllen < 0) - ereport(ERROR, - (errcode_for_file_access(), - errmsg("could not read symbolic link \"%s\": %m", - sourcepath))); - if (rllen >= sizeof(targetpath)) - ereport(ERROR, - (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED), - errmsg("symbolic link \"%s\" target is too long", - sourcepath))); - targetpath[rllen] = '\0'; + /* Get LOCATION string from its OID */ + tablespaceLoc = get_tablespace_loc_string(tablespaceOid); - PG_RETURN_TEXT_P(cstring_to_text(targetpath)); + PG_RETURN_TEXT_P(cstring_to_text(tablespaceLoc)); } /* diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 556ab057e5a..c8023e83f4b 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -18,6 +18,7 @@ #include #include #include +#include #include "access/amapi.h" #include "access/htup_details.h" diff --git a/src/include/catalog/pg_tablespace.h b/src/include/catalog/pg_tablespace.h index 5293488c630..f065cff9ddc 100644 --- a/src/include/catalog/pg_tablespace.h +++ b/src/include/catalog/pg_tablespace.h @@ -54,4 +54,6 @@ DECLARE_UNIQUE_INDEX(pg_tablespace_spcname_index, 2698, TablespaceNameIndexId, p MAKE_SYSCACHE(TABLESPACEOID, pg_tablespace_oid_index, 4); +extern char *get_tablespace_loc_string(Oid tablespaceOid); + #endif /* PG_TABLESPACE_H */ -- 2.51.2