relfilenumber.c

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/*
 *  relfilenumber.c
 *
 *  relfilenumber functions
 *
 *  Copyright (c) 2010-2025, PostgreSQL Global Development Group
 *  src/bin/pg_upgrade/relfilenumber.c
 */
 
#include "postgres_fe.h"
 
#include <sys/stat.h>
 
#include "common/file_perm.h"
#include "common/file_utils.h"
#include "common/int.h"
#include "common/logging.h"
#include "pg_upgrade.h"
 
static void transfer_single_new_db(FileNameMap *maps, int size, char *old_tablespace);
static void transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_frozenbit);
 
/*
 * The following set of sync_queue_* functions are used for --swap to reduce
 * the amount of time spent synchronizing the swapped catalog files.  When a
 * file is added to the queue, we also alert the file system that we'd like it
 * to be persisted to disk in the near future (if that operation is supported
 * by the current platform).  Once the queue is full, all of the files are
 * synchronized to disk.  This strategy should generally be much faster than
 * simply calling fsync() on the files right away.
 *
 * The general usage pattern should be something like:
 *
 *     for (int i = 0; i < num_files; i++)
 *         sync_queue_push(files[i]);
 *
 *     // be sure to sync any remaining files in the queue
 *     sync_queue_sync_all();
 *     sync_queue_destroy();
 */
 
#define SYNC_QUEUE_MAX_LEN  (1024)
 
static char *sync_queue[SYNC_QUEUE_MAX_LEN];
static bool sync_queue_inited;
static int  sync_queue_len;
 
static inline void
sync_queue_init(void)
{
    if (sync_queue_inited)
        return;
 
    sync_queue_inited = true;
    for (int i = 0; i < SYNC_QUEUE_MAX_LEN; i++)
        sync_queue[i] = palloc(MAXPGPATH);
}
 
static inline void
sync_queue_sync_all(void)
{
    if (!sync_queue_inited)
        return;
 
    for (int i = 0; i < sync_queue_len; i++)
    {
        if (fsync_fname(sync_queue[i], false) != 0)
            pg_fatal("could not synchronize file \"%s\": %m", sync_queue[i]);
    }
 
    sync_queue_len = 0;
}
 
static inline void
sync_queue_push(const char *fname)
{
    sync_queue_init();
 
    pre_sync_fname(fname, false);
 
    strncpy(sync_queue[sync_queue_len++], fname, MAXPGPATH);
    if (sync_queue_len >= SYNC_QUEUE_MAX_LEN)
        sync_queue_sync_all();
}
 
static inline void
sync_queue_destroy(void)
{
    if (!sync_queue_inited)
        return;
 
    sync_queue_inited = false;
    sync_queue_len = 0;
    for (int i = 0; i < SYNC_QUEUE_MAX_LEN; i++)
    {
        pfree(sync_queue[i]);
        sync_queue[i] = NULL;
    }
}
 
/*
 * transfer_all_new_tablespaces()
 *
 * Responsible for upgrading all database. invokes routines to generate mappings and then
 * physically link the databases.
 */
void
transfer_all_new_tablespaces(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
                             char *old_pgdata, char *new_pgdata)
{
    switch (user_opts.transfer_mode)
    {
        case TRANSFER_MODE_CLONE:
            prep_status_progress("Cloning user relation files");
            break;
        case TRANSFER_MODE_COPY:
            prep_status_progress("Copying user relation files");
            break;
        case TRANSFER_MODE_COPY_FILE_RANGE:
            prep_status_progress("Copying user relation files with copy_file_range");
            break;
        case TRANSFER_MODE_LINK:
            prep_status_progress("Linking user relation files");
            break;
        case TRANSFER_MODE_SWAP:
            prep_status_progress("Swapping data directories");
            break;
    }
 
    /*
     * Transferring files by tablespace is tricky because a single database
     * can use multiple tablespaces.  For non-parallel mode, we just pass a
     * NULL tablespace path, which matches all tablespaces.  In parallel mode,
     * we pass the default tablespace and all user-created tablespaces and let
     * those operations happen in parallel.
     */
    if (user_opts.jobs <= 1)
        parallel_transfer_all_new_dbs(old_db_arr, new_db_arr, old_pgdata,
                                      new_pgdata, NULL);
    else
    {
        int         tblnum;
 
        /* transfer default tablespace */
        parallel_transfer_all_new_dbs(old_db_arr, new_db_arr, old_pgdata,
                                      new_pgdata, old_pgdata);
 
        for (tblnum = 0; tblnum < os_info.num_old_tablespaces; tblnum++)
            parallel_transfer_all_new_dbs(old_db_arr,
                                          new_db_arr,
                                          old_pgdata,
                                          new_pgdata,
                                          os_info.old_tablespaces[tblnum]);
        /* reap all children */
        while (reap_child(true) == true)
            ;
    }
 
    end_progress_output();
    check_ok();
}
 
 
/*
 * transfer_all_new_dbs()
 *
 * Responsible for upgrading all database. invokes routines to generate mappings and then
 * physically link the databases.
 */
void
transfer_all_new_dbs(DbInfoArr *old_db_arr, DbInfoArr *new_db_arr,
                     char *old_pgdata, char *new_pgdata, char *old_tablespace)
{
    int         old_dbnum,
                new_dbnum;
 
    /* Scan the old cluster databases and transfer their files */
    for (old_dbnum = new_dbnum = 0;
         old_dbnum < old_db_arr->ndbs;
         old_dbnum++, new_dbnum++)
    {
        DbInfo     *old_db = &old_db_arr->dbs[old_dbnum],
                   *new_db = NULL;
        FileNameMap *mappings;
        int         n_maps;
 
        /*
         * Advance past any databases that exist in the new cluster but not in
         * the old, e.g. "postgres".  (The user might have removed the
         * 'postgres' database from the old cluster.)
         */
        for (; new_dbnum < new_db_arr->ndbs; new_dbnum++)
        {
            new_db = &new_db_arr->dbs[new_dbnum];
            if (strcmp(old_db->db_name, new_db->db_name) == 0)
                break;
        }
 
        if (new_dbnum >= new_db_arr->ndbs)
            pg_fatal("old database \"%s\" not found in the new cluster",
                     old_db->db_name);
 
        mappings = gen_db_file_maps(old_db, new_db, &n_maps, old_pgdata,
                                    new_pgdata);
        if (n_maps)
        {
            transfer_single_new_db(mappings, n_maps, old_tablespace);
        }
        /* We allocate something even for n_maps == 0 */
        pg_free(mappings);
    }
 
    /*
     * Make sure anything pending synchronization in swap mode is fully
     * persisted to disk.  This is a no-op for other transfer modes.
     */
    sync_queue_sync_all();
    sync_queue_destroy();
}
 
/*
 * prepare_for_swap()
 *
 * This function moves the database directory from the old cluster to the new
 * cluster in preparation for moving the pg_restore-generated catalog files
 * into place.  Returns false if the database with the given OID does not have
 * a directory in the given tablespace, otherwise returns true.
 *
 * This function will return paths in the following variables, which the caller
 * must ensure are sized to MAXPGPATH bytes:
 *
 *  old_catalog_dir: The directory for the old cluster's catalog files.
 *  new_db_dir: The new cluster's database directory for db_oid.
 *  moved_db_dir: Destination for the pg_restore-generated database directory.
 */
static bool
prepare_for_swap(const char *old_tablespace, Oid db_oid,
                 char *old_catalog_dir, char *new_db_dir, char *moved_db_dir)
{
    const char *new_tablespace;
    const char *old_tblspc_suffix;
    const char *new_tblspc_suffix;
    char        old_tblspc[MAXPGPATH];
    char        new_tblspc[MAXPGPATH];
    char        moved_tblspc[MAXPGPATH];
    char        old_db_dir[MAXPGPATH];
    struct stat st;
 
    if (strcmp(old_tablespace, old_cluster.pgdata) == 0)
    {
        new_tablespace = new_cluster.pgdata;
        new_tblspc_suffix = "/base";
        old_tblspc_suffix = "/base";
    }
    else
    {
        /*
         * XXX: The below line is a hack to deal with the fact that we
         * presently don't have an easy way to find the corresponding new
         * tablespace's path.  This will need to be fixed if/when we add
         * pg_upgrade support for in-place tablespaces.
         */
        new_tablespace = old_tablespace;
 
        new_tblspc_suffix = new_cluster.tablespace_suffix;
        old_tblspc_suffix = old_cluster.tablespace_suffix;
    }
 
    /* Old and new cluster paths. */
    snprintf(old_tblspc, sizeof(old_tblspc), "%s%s", old_tablespace, old_tblspc_suffix);
    snprintf(new_tblspc, sizeof(new_tblspc), "%s%s", new_tablespace, new_tblspc_suffix);
    snprintf(old_db_dir, sizeof(old_db_dir), "%s/%u", old_tblspc, db_oid);
    snprintf(new_db_dir, MAXPGPATH, "%s/%u", new_tblspc, db_oid);
 
    /*
     * Paths for "moved aside" stuff.  We intentionally put these in the old
     * cluster so that the delete_old_cluster.{sh,bat} script handles them.
     */
    snprintf(moved_tblspc, sizeof(moved_tblspc), "%s/moved_for_upgrade", old_tblspc);
    snprintf(old_catalog_dir, MAXPGPATH, "%s/%u_old_catalogs", moved_tblspc, db_oid);
    snprintf(moved_db_dir, MAXPGPATH, "%s/%u", moved_tblspc, db_oid);
 
    /* Check that the database directory exists in the given tablespace. */
    if (stat(old_db_dir, &st) != 0)
    {
        if (errno != ENOENT)
            pg_fatal("could not stat file \"%s\": %m", old_db_dir);
        return false;
    }
 
    /* Create directory for stuff that is moved aside. */
    if (pg_mkdir_p(moved_tblspc, pg_dir_create_mode) != 0 && errno != EEXIST)
        pg_fatal("could not create directory \"%s\"", moved_tblspc);
 
    /* Create directory for old catalog files. */
    if (pg_mkdir_p(old_catalog_dir, pg_dir_create_mode) != 0)
        pg_fatal("could not create directory \"%s\"", old_catalog_dir);
 
    /* Move the new cluster's database directory aside. */
    if (rename(new_db_dir, moved_db_dir) != 0)
        pg_fatal("could not rename \"%s\" to \"%s\"", new_db_dir, moved_db_dir);
 
    /* Move the old cluster's database directory into place. */
    if (rename(old_db_dir, new_db_dir) != 0)
        pg_fatal("could not rename \"%s\" to \"%s\"", old_db_dir, new_db_dir);
 
    return true;
}
 
/*
 * FileNameMapCmp()
 *
 * qsort() comparator for FileNameMap that sorts by RelFileNumber.
 */
static int
FileNameMapCmp(const void *a, const void *b)
{
    const FileNameMap *map1 = (const FileNameMap *) a;
    const FileNameMap *map2 = (const FileNameMap *) b;
 
    return pg_cmp_u32(map1->relfilenumber, map2->relfilenumber);
}
 
/*
 * parse_relfilenumber()
 *
 * Attempt to parse the RelFileNumber of the given file name.  If we can't,
 * return InvalidRelFileNumber.  Note that this code snippet is lifted from
 * parse_filename_for_nontemp_relation().
 */
static RelFileNumber
parse_relfilenumber(const char *filename)
{
    char       *endp;
    unsigned long n;
 
    if (filename[0] < '1' || filename[0] > '9')
        return InvalidRelFileNumber;
 
    errno = 0;
    n = strtoul(filename, &endp, 10);
    if (errno || filename == endp || n <= 0 || n > PG_UINT32_MAX)
        return InvalidRelFileNumber;
 
    return (RelFileNumber) n;
}
 
/*
 * swap_catalog_files()
 *
 * Moves the old catalog files aside, and moves the new catalog files into
 * place.  prepare_for_swap() should have already been called (and returned
 * true) for the tablespace/database being transferred.
 *
 * The arguments for the following parameters should be the corresponding
 * variables returned by prepare_for_swap():
 *
 *  old_catalog_dir: The directory for the old cluster's catalog files.
 *  new_db_dir: New cluster's database directory (for DB being transferred).
 *  moved_db_dir: Moved-aside pg_restore-generated database directory.
 */
static void
swap_catalog_files(FileNameMap *maps, int size, const char *old_catalog_dir,
                   const char *new_db_dir, const char *moved_db_dir)
{
    DIR        *dir;
    struct dirent *de;
    char        path[MAXPGPATH];
    char        dest[MAXPGPATH];
    RelFileNumber rfn;
 
    /* Move the old catalog files aside. */
    dir = opendir(new_db_dir);
    if (dir == NULL)
        pg_fatal("could not open directory \"%s\": %m", new_db_dir);
    while (errno = 0, (de = readdir(dir)) != NULL)
    {
        snprintf(path, sizeof(path), "%s/%s", new_db_dir, de->d_name);
        if (get_dirent_type(path, de, false, PG_LOG_ERROR) != PGFILETYPE_REG)
            continue;
 
        rfn = parse_relfilenumber(de->d_name);
        if (RelFileNumberIsValid(rfn))
        {
            FileNameMap key = {.relfilenumber = rfn};
 
            if (bsearch(&key, maps, size, sizeof(FileNameMap), FileNameMapCmp))
                continue;
        }
 
        snprintf(dest, sizeof(dest), "%s/%s", old_catalog_dir, de->d_name);
        if (rename(path, dest) != 0)
            pg_fatal("could not rename \"%s\" to \"%s\": %m", path, dest);
    }
    if (errno)
        pg_fatal("could not read directory \"%s\": %m", new_db_dir);
    (void) closedir(dir);
 
    /* Move the new catalog files into place. */
    dir = opendir(moved_db_dir);
    if (dir == NULL)
        pg_fatal("could not open directory \"%s\": %m", moved_db_dir);
    while (errno = 0, (de = readdir(dir)) != NULL)
    {
        snprintf(path, sizeof(path), "%s/%s", moved_db_dir, de->d_name);
        if (get_dirent_type(path, de, false, PG_LOG_ERROR) != PGFILETYPE_REG)
            continue;
 
        rfn = parse_relfilenumber(de->d_name);
        if (RelFileNumberIsValid(rfn))
        {
            FileNameMap key = {.relfilenumber = rfn};
 
            if (bsearch(&key, maps, size, sizeof(FileNameMap), FileNameMapCmp))
                continue;
        }
 
        snprintf(dest, sizeof(dest), "%s/%s", new_db_dir, de->d_name);
        if (rename(path, dest) != 0)
            pg_fatal("could not rename \"%s\" to \"%s\": %m", path, dest);
 
        /*
         * We don't fsync() the database files in the file synchronization
         * stage of pg_upgrade in swap mode, so we need to synchronize them
         * ourselves.  We only do this for the catalog files because they were
         * created during pg_restore with fsync=off.  We assume that the user
         * data files were properly persisted to disk when the user last shut
         * it down.
         */
        if (user_opts.do_sync)
            sync_queue_push(dest);
    }
    if (errno)
        pg_fatal("could not read directory \"%s\": %m", moved_db_dir);
    (void) closedir(dir);
 
    /* Ensure the directory entries are persisted to disk. */
    if (fsync_fname(new_db_dir, true) != 0)
        pg_fatal("could not synchronize directory \"%s\": %m", new_db_dir);
    if (fsync_parent_path(new_db_dir) != 0)
        pg_fatal("could not synchronize parent directory of \"%s\": %m", new_db_dir);
}
 
/*
 * do_swap()
 *
 * Perform the required steps for --swap for a single database.  In short this
 * moves the old cluster's database directory into the new cluster and then
 * replaces any files for system catalogs with the ones that were generated
 * during pg_restore.
 */
static void
do_swap(FileNameMap *maps, int size, char *old_tablespace)
{
    char        old_catalog_dir[MAXPGPATH];
    char        new_db_dir[MAXPGPATH];
    char        moved_db_dir[MAXPGPATH];
 
    /*
     * We perform many lookups on maps by relfilenumber in swap mode, so make
     * sure it's sorted by relfilenumber.  maps should already be sorted by
     * OID, so in general this shouldn't have much work to do.
     */
    qsort(maps, size, sizeof(FileNameMap), FileNameMapCmp);
 
    /*
     * If an old tablespace is given, we only need to process that one.  If no
     * old tablespace is specified, we need to process all the tablespaces on
     * the system.
     */
    if (old_tablespace)
    {
        if (prepare_for_swap(old_tablespace, maps[0].db_oid,
                             old_catalog_dir, new_db_dir, moved_db_dir))
            swap_catalog_files(maps, size,
                               old_catalog_dir, new_db_dir, moved_db_dir);
    }
    else
    {
        if (prepare_for_swap(old_cluster.pgdata, maps[0].db_oid,
                             old_catalog_dir, new_db_dir, moved_db_dir))
            swap_catalog_files(maps, size,
                               old_catalog_dir, new_db_dir, moved_db_dir);
 
        for (int tblnum = 0; tblnum < os_info.num_old_tablespaces; tblnum++)
        {
            if (prepare_for_swap(os_info.old_tablespaces[tblnum], maps[0].db_oid,
                                 old_catalog_dir, new_db_dir, moved_db_dir))
                swap_catalog_files(maps, size,
                                   old_catalog_dir, new_db_dir, moved_db_dir);
        }
    }
}
 
/*
 * transfer_single_new_db()
 *
 * create links for mappings stored in "maps" array.
 */
static void
transfer_single_new_db(FileNameMap *maps, int size, char *old_tablespace)
{
    int         mapnum;
    bool        vm_must_add_frozenbit = false;
 
    /*
     * Do we need to rewrite visibilitymap?
     */
    if (old_cluster.controldata.cat_ver < VISIBILITY_MAP_FROZEN_BIT_CAT_VER &&
        new_cluster.controldata.cat_ver >= VISIBILITY_MAP_FROZEN_BIT_CAT_VER)
        vm_must_add_frozenbit = true;
 
    /* --swap has its own subroutine */
    if (user_opts.transfer_mode == TRANSFER_MODE_SWAP)
    {
        /*
         * We don't support --swap to upgrade from versions that require
         * rewriting the visibility map.  We should've failed already if
         * someone tries to do that.
         */
        Assert(!vm_must_add_frozenbit);
 
        do_swap(maps, size, old_tablespace);
        return;
    }
 
    for (mapnum = 0; mapnum < size; mapnum++)
    {
        if (old_tablespace == NULL ||
            strcmp(maps[mapnum].old_tablespace, old_tablespace) == 0)
        {
            /* transfer primary file */
            transfer_relfile(&maps[mapnum], "", vm_must_add_frozenbit);
 
            /*
             * Copy/link any fsm and vm files, if they exist
             */
            transfer_relfile(&maps[mapnum], "_fsm", vm_must_add_frozenbit);
            transfer_relfile(&maps[mapnum], "_vm", vm_must_add_frozenbit);
        }
    }
}
 
 
/*
 * transfer_relfile()
 *
 * Copy or link file from old cluster to new one.  If vm_must_add_frozenbit
 * is true, visibility map forks are converted and rewritten, even in link
 * mode.
 */
static void
transfer_relfile(FileNameMap *map, const char *type_suffix, bool vm_must_add_frozenbit)
{
    char        old_file[MAXPGPATH];
    char        new_file[MAXPGPATH];
    int         segno;
    char        extent_suffix[65];
    struct stat statbuf;
 
    /*
     * Now copy/link any related segments as well. Remember, PG breaks large
     * files into 1GB segments, the first segment has no extension, subsequent
     * segments are named relfilenumber.1, relfilenumber.2, relfilenumber.3.
     */
    for (segno = 0;; segno++)
    {
        if (segno == 0)
            extent_suffix[0] = '\0';
        else
            snprintf(extent_suffix, sizeof(extent_suffix), ".%d", segno);
 
        snprintf(old_file, sizeof(old_file), "%s%s/%u/%u%s%s",
                 map->old_tablespace,
                 map->old_tablespace_suffix,
                 map->db_oid,
                 map->relfilenumber,
                 type_suffix,
                 extent_suffix);
        snprintf(new_file, sizeof(new_file), "%s%s/%u/%u%s%s",
                 map->new_tablespace,
                 map->new_tablespace_suffix,
                 map->db_oid,
                 map->relfilenumber,
                 type_suffix,
                 extent_suffix);
 
        /* Is it an extent, fsm, or vm file? */
        if (type_suffix[0] != '\0' || segno != 0)
        {
            /* Did file open fail? */
            if (stat(old_file, &statbuf) != 0)
            {
                /* File does not exist?  That's OK, just return */
                if (errno == ENOENT)
                    return;
                else
                    pg_fatal("error while checking for file existence \"%s.%s\" (\"%s\" to \"%s\"): %m",
                             map->nspname, map->relname, old_file, new_file);
            }
 
            /* If file is empty, just return */
            if (statbuf.st_size == 0)
                return;
        }
 
        unlink(new_file);
 
        /* Copying files might take some time, so give feedback. */
        pg_log(PG_STATUS, "%s", old_file);
 
        if (vm_must_add_frozenbit && strcmp(type_suffix, "_vm") == 0)
        {
            /* Need to rewrite visibility map format */
            pg_log(PG_VERBOSE, "rewriting \"%s\" to \"%s\"",
                   old_file, new_file);
            rewriteVisibilityMap(old_file, new_file, map->nspname, map->relname);
        }
        else
            switch (user_opts.transfer_mode)
            {
                case TRANSFER_MODE_CLONE:
                    pg_log(PG_VERBOSE, "cloning \"%s\" to \"%s\"",
                           old_file, new_file);
                    cloneFile(old_file, new_file, map->nspname, map->relname);
                    break;
                case TRANSFER_MODE_COPY:
                    pg_log(PG_VERBOSE, "copying \"%s\" to \"%s\"",
                           old_file, new_file);
                    copyFile(old_file, new_file, map->nspname, map->relname);
                    break;
                case TRANSFER_MODE_COPY_FILE_RANGE:
                    pg_log(PG_VERBOSE, "copying \"%s\" to \"%s\" with copy_file_range",
                           old_file, new_file);
                    copyFileByRange(old_file, new_file, map->nspname, map->relname);
                    break;
                case TRANSFER_MODE_LINK:
                    pg_log(PG_VERBOSE, "linking \"%s\" to \"%s\"",
                           old_file, new_file);
                    linkFile(old_file, new_file, map->nspname, map->relname);
                    break;
                case TRANSFER_MODE_SWAP:
                    /* swap mode is handled in its own code path */
                    pg_fatal("should never happen");
                    break;
            }
    }
}