tablespace.c

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/*
 *  tablespace.c
 *
 *  tablespace functions
 *
 *  Copyright (c) 2010-2025, PostgreSQL Global Development Group
 *  src/bin/pg_upgrade/tablespace.c
 */
 
#include "postgres_fe.h"
 
#include "pg_upgrade.h"
 
static void get_tablespace_paths(void);
static void set_tablespace_directory_suffix(ClusterInfo *cluster);
 
 
void
init_tablespaces(void)
{
    get_tablespace_paths();
 
    set_tablespace_directory_suffix(&old_cluster);
    set_tablespace_directory_suffix(&new_cluster);
 
    if (old_cluster.num_tablespaces > 0 &&
        strcmp(old_cluster.tablespace_suffix, new_cluster.tablespace_suffix) == 0)
    {
        for (int i = 0; i < old_cluster.num_tablespaces; i++)
        {
            /*
             * In-place tablespaces are okay for same-version upgrades because
             * their paths will differ between clusters.
             */
            if (strcmp(old_cluster.tablespaces[i], new_cluster.tablespaces[i]) == 0)
                pg_fatal("Cannot upgrade to/from the same system catalog version when\n"
                         "using tablespaces.");
        }
    }
}
 
 
/*
 * get_tablespace_paths()
 *
 * Scans pg_tablespace and returns a malloc'ed array of all tablespace
 * paths. It's the caller's responsibility to free the array.
 */
static void
get_tablespace_paths(void)
{
    PGconn     *conn = connectToServer(&old_cluster, "template1");
    PGresult   *res;
    int         tblnum;
    int         i_spclocation;
    char        query[QUERY_ALLOC];
 
    snprintf(query, sizeof(query),
             "SELECT pg_catalog.pg_tablespace_location(oid) AS spclocation "
             "FROM  pg_catalog.pg_tablespace "
             "WHERE spcname != 'pg_default' AND "
             "      spcname != 'pg_global'");
 
    res = executeQueryOrDie(conn, "%s", query);
 
    old_cluster.num_tablespaces = PQntuples(res);
    new_cluster.num_tablespaces = PQntuples(res);
 
    if (PQntuples(res) != 0)
    {
        old_cluster.tablespaces =
            (char **) pg_malloc(old_cluster.num_tablespaces * sizeof(char *));
        new_cluster.tablespaces =
            (char **) pg_malloc(new_cluster.num_tablespaces * sizeof(char *));
    }
    else
    {
        old_cluster.tablespaces = NULL;
        new_cluster.tablespaces = NULL;
    }
 
    i_spclocation = PQfnumber(res, "spclocation");
 
    for (tblnum = 0; tblnum < old_cluster.num_tablespaces; tblnum++)
    {
        struct stat statBuf;
        char       *spcloc = PQgetvalue(res, tblnum, i_spclocation);
 
        /*
         * For now, we do not expect non-in-place tablespaces to move during
         * upgrade.  If that changes, it will likely become necessary to run
         * the above query on the new cluster, too.
         *
         * pg_tablespace_location() returns absolute paths for non-in-place
         * tablespaces and relative paths for in-place ones, so we use
         * is_absolute_path() to distinguish between them.
         */
        if (is_absolute_path(PQgetvalue(res, tblnum, i_spclocation)))
        {
            old_cluster.tablespaces[tblnum] = pg_strdup(spcloc);
            new_cluster.tablespaces[tblnum] = old_cluster.tablespaces[tblnum];
        }
        else
        {
            old_cluster.tablespaces[tblnum] = psprintf("%s/%s", old_cluster.pgdata, spcloc);
            new_cluster.tablespaces[tblnum] = psprintf("%s/%s", new_cluster.pgdata, spcloc);
        }
 
        /*
         * Check that the tablespace path exists and is a directory.
         * Effectively, this is checking only for tables/indexes in
         * non-existent tablespace directories.  Databases located in
         * non-existent tablespaces already throw a backend error.
         * Non-existent tablespace directories can occur when a data directory
         * that contains user tablespaces is moved as part of pg_upgrade
         * preparation and the symbolic links are not updated.
         */
        if (stat(old_cluster.tablespaces[tblnum], &statBuf) != 0)
        {
            if (errno == ENOENT)
                report_status(PG_FATAL,
                              "tablespace directory \"%s\" does not exist",
                              old_cluster.tablespaces[tblnum]);
            else
                report_status(PG_FATAL,
                              "could not stat tablespace directory \"%s\": %m",
                              old_cluster.tablespaces[tblnum]);
        }
        if (!S_ISDIR(statBuf.st_mode))
            report_status(PG_FATAL,
                          "tablespace path \"%s\" is not a directory",
                          old_cluster.tablespaces[tblnum]);
    }
 
    PQclear(res);
 
    PQfinish(conn);
}
 
 
static void
set_tablespace_directory_suffix(ClusterInfo *cluster)
{
    /* This cluster has a version-specific subdirectory */
 
    /* The leading slash is needed to start a new directory. */
    cluster->tablespace_suffix = psprintf("/PG_%s_%d",
                                          cluster->major_version_str,
                                          cluster->controldata.cat_ver);
}