info.c

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/*
 *  info.c
 *
 *  information support functions
 *
 *  Copyright (c) 2010-2020, PostgreSQL Global Development Group
 *  src/bin/pg_upgrade/info.c
 */

#include "postgres_fe.h"

#include "access/transam.h"
#include "catalog/pg_class_d.h"
#include "pg_upgrade.h"

static void create_rel_filename_map(const char *old_data, const char *new_data,
                                    const DbInfo *old_db, const DbInfo *new_db,
                                    const RelInfo *old_rel, const RelInfo *new_rel,
                                    FileNameMap *map);
static void report_unmatched_relation(const RelInfo *rel, const DbInfo *db,
                                      bool is_new_db);
static void free_db_and_rel_infos(DbInfoArr *db_arr);
static void get_db_infos(ClusterInfo *cluster);
static void get_rel_infos(ClusterInfo *cluster, DbInfo *dbinfo);
static void free_rel_infos(RelInfoArr *rel_arr);
static void print_db_infos(DbInfoArr *dbinfo);
static void print_rel_infos(RelInfoArr *rel_arr);


/*
 * gen_db_file_maps()
 *
 * generates a database mapping from "old_db" to "new_db".
 *
 * Returns a malloc'ed array of mappings.  The length of the array
 * is returned into *nmaps.
 */
FileNameMap *
gen_db_file_maps(DbInfo *old_db, DbInfo *new_db,
                 int *nmaps,
                 const char *old_pgdata, const char *new_pgdata)
{
    FileNameMap *maps;
    int         old_relnum,
                new_relnum;
    int         num_maps = 0;
    bool        all_matched = true;

    /* There will certainly not be more mappings than there are old rels */
    maps = (FileNameMap *) pg_malloc(sizeof(FileNameMap) *
                                     old_db->rel_arr.nrels);

    /*
     * Each of the RelInfo arrays should be sorted by OID.  Scan through them
     * and match them up.  If we fail to match everything, we'll abort, but
     * first print as much info as we can about mismatches.
     */
    old_relnum = new_relnum = 0;
    while (old_relnum < old_db->rel_arr.nrels ||
           new_relnum < new_db->rel_arr.nrels)
    {
        RelInfo    *old_rel = (old_relnum < old_db->rel_arr.nrels) ?
        &old_db->rel_arr.rels[old_relnum] : NULL;
        RelInfo    *new_rel = (new_relnum < new_db->rel_arr.nrels) ?
        &new_db->rel_arr.rels[new_relnum] : NULL;

        /* handle running off one array before the other */
        if (!new_rel)
        {
            /*
             * old_rel is unmatched.  This should never happen, because we
             * force new rels to have TOAST tables if the old one did.
             */
            report_unmatched_relation(old_rel, old_db, false);
            all_matched = false;
            old_relnum++;
            continue;
        }
        if (!old_rel)
        {
            /*
             * new_rel is unmatched.  This shouldn't really happen either, but
             * if it's a TOAST table, we can ignore it and continue
             * processing, assuming that the new server made a TOAST table
             * that wasn't needed.
             */
            if (strcmp(new_rel->nspname, "pg_toast") != 0)
            {
                report_unmatched_relation(new_rel, new_db, true);
                all_matched = false;
            }
            new_relnum++;
            continue;
        }

        /* check for mismatched OID */
        if (old_rel->reloid < new_rel->reloid)
        {
            /* old_rel is unmatched, see comment above */
            report_unmatched_relation(old_rel, old_db, false);
            all_matched = false;
            old_relnum++;
            continue;
        }
        else if (old_rel->reloid > new_rel->reloid)
        {
            /* new_rel is unmatched, see comment above */
            if (strcmp(new_rel->nspname, "pg_toast") != 0)
            {
                report_unmatched_relation(new_rel, new_db, true);
                all_matched = false;
            }
            new_relnum++;
            continue;
        }

        /*
         * Verify that rels of same OID have same name.  The namespace name
         * should always match, but the relname might not match for TOAST
         * tables (and, therefore, their indexes).
         *
         * TOAST table names initially match the heap pg_class oid, but
         * pre-9.0 they can change during certain commands such as CLUSTER, so
         * don't insist on a match if old cluster is < 9.0.
         */
        if (strcmp(old_rel->nspname, new_rel->nspname) != 0 ||
            (strcmp(old_rel->relname, new_rel->relname) != 0 &&
             (GET_MAJOR_VERSION(old_cluster.major_version) >= 900 ||
              strcmp(old_rel->nspname, "pg_toast") != 0)))
        {
            pg_log(PG_WARNING, "Relation names for OID %u in database \"%s\" do not match: "
                   "old name \"%s.%s\", new name \"%s.%s\"\n",
                   old_rel->reloid, old_db->db_name,
                   old_rel->nspname, old_rel->relname,
                   new_rel->nspname, new_rel->relname);
            all_matched = false;
            old_relnum++;
            new_relnum++;
            continue;
        }

        /* OK, create a mapping entry */
        create_rel_filename_map(old_pgdata, new_pgdata, old_db, new_db,
                                old_rel, new_rel, maps + num_maps);
        num_maps++;
        old_relnum++;
        new_relnum++;
    }

    if (!all_matched)
        pg_fatal("Failed to match up old and new tables in database \"%s\"\n",
                 old_db->db_name);

    *nmaps = num_maps;
    return maps;
}


/*
 * create_rel_filename_map()
 *
 * fills a file node map structure and returns it in "map".
 */
static void
create_rel_filename_map(const char *old_data, const char *new_data,
                        const DbInfo *old_db, const DbInfo *new_db,
                        const RelInfo *old_rel, const RelInfo *new_rel,
                        FileNameMap *map)
{
    /* In case old/new tablespaces don't match, do them separately. */
    if (strlen(old_rel->tablespace) == 0)
    {
        /*
         * relation belongs to the default tablespace, hence relfiles should
         * exist in the data directories.
         */
        map->old_tablespace = old_data;
        map->old_tablespace_suffix = "/base";
    }
    else
    {
        /* relation belongs to a tablespace, so use the tablespace location */
        map->old_tablespace = old_rel->tablespace;
        map->old_tablespace_suffix = old_cluster.tablespace_suffix;
    }

    /* Do the same for new tablespaces */
    if (strlen(new_rel->tablespace) == 0)
    {
        map->new_tablespace = new_data;
        map->new_tablespace_suffix = "/base";
    }
    else
    {
        map->new_tablespace = new_rel->tablespace;
        map->new_tablespace_suffix = new_cluster.tablespace_suffix;
    }

    map->old_db_oid = old_db->db_oid;
    map->new_db_oid = new_db->db_oid;

    /*
     * old_relfilenode might differ from pg_class.oid (and hence
     * new_relfilenode) because of CLUSTER, REINDEX, or VACUUM FULL.
     */
    map->old_relfilenode = old_rel->relfilenode;

    /* new_relfilenode will match old and new pg_class.oid */
    map->new_relfilenode = new_rel->relfilenode;

    /* used only for logging and error reporting, old/new are identical */
    map->nspname = old_rel->nspname;
    map->relname = old_rel->relname;
}


/*
 * Complain about a relation we couldn't match to the other database,
 * identifying it as best we can.
 */
static void
report_unmatched_relation(const RelInfo *rel, const DbInfo *db, bool is_new_db)
{
    Oid         reloid = rel->reloid;   /* we might change rel below */
    char        reldesc[1000];
    int         i;

    snprintf(reldesc, sizeof(reldesc), "\"%s.%s\"",
             rel->nspname, rel->relname);
    if (rel->indtable)
    {
        for (i = 0; i < db->rel_arr.nrels; i++)
        {
            const RelInfo *hrel = &db->rel_arr.rels[i];

            if (hrel->reloid == rel->indtable)
            {
                snprintf(reldesc + strlen(reldesc),
                         sizeof(reldesc) - strlen(reldesc),
                         _(" which is an index on \"%s.%s\""),
                         hrel->nspname, hrel->relname);
                /* Shift attention to index's table for toast check */
                rel = hrel;
                break;
            }
        }
        if (i >= db->rel_arr.nrels)
            snprintf(reldesc + strlen(reldesc),
                     sizeof(reldesc) - strlen(reldesc),
                     _(" which is an index on OID %u"), rel->indtable);
    }
    if (rel->toastheap)
    {
        for (i = 0; i < db->rel_arr.nrels; i++)
        {
            const RelInfo *brel = &db->rel_arr.rels[i];

            if (brel->reloid == rel->toastheap)
            {
                snprintf(reldesc + strlen(reldesc),
                         sizeof(reldesc) - strlen(reldesc),
                         _(" which is the TOAST table for \"%s.%s\""),
                         brel->nspname, brel->relname);
                break;
            }
        }
        if (i >= db->rel_arr.nrels)
            snprintf(reldesc + strlen(reldesc),
                     sizeof(reldesc) - strlen(reldesc),
                     _(" which is the TOAST table for OID %u"), rel->toastheap);
    }

    if (is_new_db)
        pg_log(PG_WARNING, "No match found in old cluster for new relation with OID %u in database \"%s\": %s\n",
               reloid, db->db_name, reldesc);
    else
        pg_log(PG_WARNING, "No match found in new cluster for old relation with OID %u in database \"%s\": %s\n",
               reloid, db->db_name, reldesc);
}


void
print_maps(FileNameMap *maps, int n_maps, const char *db_name)
{
    if (log_opts.verbose)
    {
        int         mapnum;

        pg_log(PG_VERBOSE, "mappings for database \"%s\":\n", db_name);

        for (mapnum = 0; mapnum < n_maps; mapnum++)
            pg_log(PG_VERBOSE, "%s.%s: %u to %u\n",
                   maps[mapnum].nspname, maps[mapnum].relname,
                   maps[mapnum].old_relfilenode,
                   maps[mapnum].new_relfilenode);

        pg_log(PG_VERBOSE, "\n\n");
    }
}


/*
 * get_db_and_rel_infos()
 *
 * higher level routine to generate dbinfos for the database running
 * on the given "port". Assumes that server is already running.
 */
void
get_db_and_rel_infos(ClusterInfo *cluster)
{
    int         dbnum;

    if (cluster->dbarr.dbs != NULL)
        free_db_and_rel_infos(&cluster->dbarr);

    get_db_infos(cluster);

    for (dbnum = 0; dbnum < cluster->dbarr.ndbs; dbnum++)
        get_rel_infos(cluster, &cluster->dbarr.dbs[dbnum]);

    if (cluster == &old_cluster)
        pg_log(PG_VERBOSE, "\nsource databases:\n");
    else
        pg_log(PG_VERBOSE, "\ntarget databases:\n");

    if (log_opts.verbose)
        print_db_infos(&cluster->dbarr);
}


/*
 * get_db_infos()
 *
 * Scans pg_database system catalog and populates all user
 * databases.
 */
static void
get_db_infos(ClusterInfo *cluster)
{
    PGconn     *conn = connectToServer(cluster, "template1");
    PGresult   *res;
    int         ntups;
    int         tupnum;
    DbInfo     *dbinfos;
    int         i_datname,
                i_oid,
                i_encoding,
                i_datcollate,
                i_datctype,
                i_spclocation;
    char        query[QUERY_ALLOC];

    snprintf(query, sizeof(query),
             "SELECT d.oid, d.datname, d.encoding, d.datcollate, d.datctype, "
             "%s AS spclocation "
             "FROM pg_catalog.pg_database d "
             " LEFT OUTER JOIN pg_catalog.pg_tablespace t "
             " ON d.dattablespace = t.oid "
             "WHERE d.datallowconn = true "
    /* we don't preserve pg_database.oid so we sort by name */
             "ORDER BY 2",
    /* 9.2 removed the spclocation column */
             (GET_MAJOR_VERSION(cluster->major_version) <= 901) ?
             "t.spclocation" : "pg_catalog.pg_tablespace_location(t.oid)");

    res = executeQueryOrDie(conn, "%s", query);

    i_oid = PQfnumber(res, "oid");
    i_datname = PQfnumber(res, "datname");
    i_encoding = PQfnumber(res, "encoding");
    i_datcollate = PQfnumber(res, "datcollate");
    i_datctype = PQfnumber(res, "datctype");
    i_spclocation = PQfnumber(res, "spclocation");

    ntups = PQntuples(res);
    dbinfos = (DbInfo *) pg_malloc(sizeof(DbInfo) * ntups);

    for (tupnum = 0; tupnum < ntups; tupnum++)
    {
        dbinfos[tupnum].db_oid = atooid(PQgetvalue(res, tupnum, i_oid));
        dbinfos[tupnum].db_name = pg_strdup(PQgetvalue(res, tupnum, i_datname));
        dbinfos[tupnum].db_encoding = atoi(PQgetvalue(res, tupnum, i_encoding));
        dbinfos[tupnum].db_collate = pg_strdup(PQgetvalue(res, tupnum, i_datcollate));
        dbinfos[tupnum].db_ctype = pg_strdup(PQgetvalue(res, tupnum, i_datctype));
        snprintf(dbinfos[tupnum].db_tablespace, sizeof(dbinfos[tupnum].db_tablespace), "%s",
                 PQgetvalue(res, tupnum, i_spclocation));
    }
    PQclear(res);

    PQfinish(conn);

    cluster->dbarr.dbs = dbinfos;
    cluster->dbarr.ndbs = ntups;
}


/*
 * get_rel_infos()
 *
 * gets the relinfos for all the user tables and indexes of the database
 * referred to by "dbinfo".
 *
 * Note: the resulting RelInfo array is assumed to be sorted by OID.
 * This allows later processing to match up old and new databases efficiently.
 */
static void
get_rel_infos(ClusterInfo *cluster, DbInfo *dbinfo)
{
    PGconn     *conn = connectToServer(cluster,
                                       dbinfo->db_name);
    PGresult   *res;
    RelInfo    *relinfos;
    int         ntups;
    int         relnum;
    int         num_rels = 0;
    char       *nspname = NULL;
    char       *relname = NULL;
    char       *tablespace = NULL;
    int         i_spclocation,
                i_nspname,
                i_relname,
                i_reloid,
                i_indtable,
                i_toastheap,
                i_relfilenode,
                i_reltablespace;
    char        query[QUERY_ALLOC];
    char       *last_namespace = NULL,
               *last_tablespace = NULL;

    query[0] = '\0';            /* initialize query string to empty */

    /*
     * Create a CTE that collects OIDs of regular user tables, including
     * matviews and sequences, but excluding toast tables and indexes.  We
     * assume that relations with OIDs >= FirstNormalObjectId belong to the
     * user.  (That's probably redundant with the namespace-name exclusions,
     * but let's be safe.)
     *
     * pg_largeobject contains user data that does not appear in pg_dump
     * output, so we have to copy that system table.  It's easiest to do that
     * by treating it as a user table.
     */
    snprintf(query + strlen(query), sizeof(query) - strlen(query),
             "WITH regular_heap (reloid, indtable, toastheap) AS ( "
             "  SELECT c.oid, 0::oid, 0::oid "
             "  FROM pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n "
             "         ON c.relnamespace = n.oid "
             "  WHERE relkind IN (" CppAsString2(RELKIND_RELATION) ", "
             CppAsString2(RELKIND_MATVIEW) ") AND "
    /* exclude possible orphaned temp tables */
             "    ((n.nspname !~ '^pg_temp_' AND "
             "      n.nspname !~ '^pg_toast_temp_' AND "
             "      n.nspname NOT IN ('pg_catalog', 'information_schema', "
             "                        'binary_upgrade', 'pg_toast') AND "
             "      c.oid >= %u::pg_catalog.oid) OR "
             "     (n.nspname = 'pg_catalog' AND "
             "      relname IN ('pg_largeobject') ))), ",
             FirstNormalObjectId);

    /*
     * Add a CTE that collects OIDs of toast tables belonging to the tables
     * selected by the regular_heap CTE.  (We have to do this separately
     * because the namespace-name rules above don't work for toast tables.)
     */
    snprintf(query + strlen(query), sizeof(query) - strlen(query),
             "  toast_heap (reloid, indtable, toastheap) AS ( "
             "  SELECT c.reltoastrelid, 0::oid, c.oid "
             "  FROM regular_heap JOIN pg_catalog.pg_class c "
             "      ON regular_heap.reloid = c.oid "
             "  WHERE c.reltoastrelid != 0), ");

    /*
     * Add a CTE that collects OIDs of all valid indexes on the previously
     * selected tables.  We can ignore invalid indexes since pg_dump does.
     * Testing indisready is necessary in 9.2, and harmless in earlier/later
     * versions.
     */
    snprintf(query + strlen(query), sizeof(query) - strlen(query),
             "  all_index (reloid, indtable, toastheap) AS ( "
             "  SELECT indexrelid, indrelid, 0::oid "
             "  FROM pg_catalog.pg_index "
             "  WHERE indisvalid AND indisready "
             "    AND indrelid IN "
             "        (SELECT reloid FROM regular_heap "
             "         UNION ALL "
             "         SELECT reloid FROM toast_heap)) ");

    /*
     * And now we can write the query that retrieves the data we want for each
     * heap and index relation.  Make sure result is sorted by OID.
     */
    snprintf(query + strlen(query), sizeof(query) - strlen(query),
             "SELECT all_rels.*, n.nspname, c.relname, "
             "  c.relfilenode, c.reltablespace, %s "
             "FROM (SELECT * FROM regular_heap "
             "      UNION ALL "
             "      SELECT * FROM toast_heap "
             "      UNION ALL "
             "      SELECT * FROM all_index) all_rels "
             "  JOIN pg_catalog.pg_class c "
             "      ON all_rels.reloid = c.oid "
             "  JOIN pg_catalog.pg_namespace n "
             "     ON c.relnamespace = n.oid "
             "  LEFT OUTER JOIN pg_catalog.pg_tablespace t "
             "     ON c.reltablespace = t.oid "
             "ORDER BY 1;",
    /* 9.2 removed the pg_tablespace.spclocation column */
             (GET_MAJOR_VERSION(cluster->major_version) >= 902) ?
             "pg_catalog.pg_tablespace_location(t.oid) AS spclocation" :
             "t.spclocation");

    res = executeQueryOrDie(conn, "%s", query);

    ntups = PQntuples(res);

    relinfos = (RelInfo *) pg_malloc(sizeof(RelInfo) * ntups);

    i_reloid = PQfnumber(res, "reloid");
    i_indtable = PQfnumber(res, "indtable");
    i_toastheap = PQfnumber(res, "toastheap");
    i_nspname = PQfnumber(res, "nspname");
    i_relname = PQfnumber(res, "relname");
    i_relfilenode = PQfnumber(res, "relfilenode");
    i_reltablespace = PQfnumber(res, "reltablespace");
    i_spclocation = PQfnumber(res, "spclocation");

    for (relnum = 0; relnum < ntups; relnum++)
    {
        RelInfo    *curr = &relinfos[num_rels++];

        curr->reloid = atooid(PQgetvalue(res, relnum, i_reloid));
        curr->indtable = atooid(PQgetvalue(res, relnum, i_indtable));
        curr->toastheap = atooid(PQgetvalue(res, relnum, i_toastheap));

        nspname = PQgetvalue(res, relnum, i_nspname);
        curr->nsp_alloc = false;

        /*
         * Many of the namespace and tablespace strings are identical, so we
         * try to reuse the allocated string pointers where possible to reduce
         * memory consumption.
         */
        /* Can we reuse the previous string allocation? */
        if (last_namespace && strcmp(nspname, last_namespace) == 0)
            curr->nspname = last_namespace;
        else
        {
            last_namespace = curr->nspname = pg_strdup(nspname);
            curr->nsp_alloc = true;
        }

        relname = PQgetvalue(res, relnum, i_relname);
        curr->relname = pg_strdup(relname);

        curr->relfilenode = atooid(PQgetvalue(res, relnum, i_relfilenode));
        curr->tblsp_alloc = false;

        /* Is the tablespace oid non-default? */
        if (atooid(PQgetvalue(res, relnum, i_reltablespace)) != 0)
        {
            /*
             * The tablespace location might be "", meaning the cluster
             * default location, i.e. pg_default or pg_global.
             */
            tablespace = PQgetvalue(res, relnum, i_spclocation);

            /* Can we reuse the previous string allocation? */
            if (last_tablespace && strcmp(tablespace, last_tablespace) == 0)
                curr->tablespace = last_tablespace;
            else
            {
                last_tablespace = curr->tablespace = pg_strdup(tablespace);
                curr->tblsp_alloc = true;
            }
        }
        else
            /* A zero reltablespace oid indicates the database tablespace. */
            curr->tablespace = dbinfo->db_tablespace;
    }
    PQclear(res);

    PQfinish(conn);

    dbinfo->rel_arr.rels = relinfos;
    dbinfo->rel_arr.nrels = num_rels;
}


static void
free_db_and_rel_infos(DbInfoArr *db_arr)
{
    int         dbnum;

    for (dbnum = 0; dbnum < db_arr->ndbs; dbnum++)
    {
        free_rel_infos(&db_arr->dbs[dbnum].rel_arr);
        pg_free(db_arr->dbs[dbnum].db_name);
    }
    pg_free(db_arr->dbs);
    db_arr->dbs = NULL;
    db_arr->ndbs = 0;
}


static void
free_rel_infos(RelInfoArr *rel_arr)
{
    int         relnum;

    for (relnum = 0; relnum < rel_arr->nrels; relnum++)
    {
        if (rel_arr->rels[relnum].nsp_alloc)
            pg_free(rel_arr->rels[relnum].nspname);
        pg_free(rel_arr->rels[relnum].relname);
        if (rel_arr->rels[relnum].tblsp_alloc)
            pg_free(rel_arr->rels[relnum].tablespace);
    }
    pg_free(rel_arr->rels);
    rel_arr->nrels = 0;
}


static void
print_db_infos(DbInfoArr *db_arr)
{
    int         dbnum;

    for (dbnum = 0; dbnum < db_arr->ndbs; dbnum++)
    {
        pg_log(PG_VERBOSE, "Database: %s\n", db_arr->dbs[dbnum].db_name);
        print_rel_infos(&db_arr->dbs[dbnum].rel_arr);
        pg_log(PG_VERBOSE, "\n\n");
    }
}


static void
print_rel_infos(RelInfoArr *rel_arr)
{
    int         relnum;

    for (relnum = 0; relnum < rel_arr->nrels; relnum++)
        pg_log(PG_VERBOSE, "relname: %s.%s: reloid: %u reltblspace: %s\n",
               rel_arr->rels[relnum].nspname,
               rel_arr->rels[relnum].relname,
               rel_arr->rels[relnum].reloid,
               rel_arr->rels[relnum].tablespace);
}