src/bin/pg_upgrade/relfilenode.c

/*
 *	relfilenode.c
 *
 *	relfilenode functions
 *
 *	Copyright (c) 2010-2021, PostgreSQL Global Development Group
 *	src/bin/pg_upgrade/relfilenode.c
 */

#include "postgres_fe.h"

#include <sys/stat.h>

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

#include "access/aomd.h"
#include "access/appendonlytid.h"
#include "access/htup_details.h"

#include "greenplum/pg_upgrade_greenplum.h"

static void transfer_single_new_db(FileNameMap *maps, int size, char *old_tablespace);
static void transfer_relfile(FileNameMap *map, const char *suffix, bool vm_must_add_frozenbit);

static bool transfer_relfile_segment(int segno, FileNameMap *map, const char *suffix, bool vm_must_add_frozenbit);
static void transfer_ao(FileNameMap *map);
static bool transfer_ao_perFile(const int segno, void *ctx);

/*
 * 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_LINK:
			prep_status_progress("Linking user relation files");
			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.
	 *
	 * GPDB: Disable pg_upgrade's broken parallel tablespace transfer to make the rest
	 * of the parallelism from the --jobs flag usable now to get a performance
	 * boost.
	 */
	if (true) /* (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\n",
					 old_db->db_name);

		mappings = gen_db_file_maps(old_db, new_db, &n_maps, old_pgdata,
									new_pgdata);
		if (n_maps)
		{
			print_maps(mappings, n_maps, new_db->db_name);

			transfer_single_new_db(mappings, n_maps, old_tablespace);
		}
		/* We allocate something even for n_maps == 0 */
		pg_free(mappings);
	}
}

/*
 * 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;

	for (mapnum = 0; mapnum < size; mapnum++)
	{
		if (old_tablespace == NULL ||
			strcmp(maps[mapnum].old_tablespace, old_tablespace) == 0)
		{
			RelType type = maps[mapnum].type;

			if (type == AO || type == AOCS)
			{
				transfer_ao(&maps[mapnum]);
			}
			else
			{
				/* 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)
{
	int			segno;

	/*
	 * 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 relfilenode.1, relfilenode.2, relfilenode.3.
	 */
	for (segno = 0;; segno++)
	{
		if (!transfer_relfile_segment(segno, map, type_suffix, vm_must_add_frozenbit))
			break;
	}
}

/*
 * GPDB: the body of transfer_relfile(), above, has moved into this function to
 * facilitate the implementation of transfer_ao().
 *
 * Returns true if the segment file was found, and false if it was not. Failures
 * during transfer are fatal. The case where we cannot find the segment-zero
 * file (the one without an extent suffix) for a relation is also fatal, since
 * we expect that to exist for both heap and AO tables in any case.
 *
 * GPDB_UPGRADE_FIXME: verify that AO tables must always have a segment zero.
 */
static bool
transfer_relfile_segment(int segno, FileNameMap *map,
						 const char *type_suffix, bool vm_must_add_frozenbit)
{
	char		old_file[MAXPGPATH * 3];
	char		new_file[MAXPGPATH * 3];
	char		extent_suffix[65];
	struct stat statbuf;

	/*
	 * Extra indentation is on purpose, to reduce merge conflicts with upstream.
	 */

	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->old_db_oid,
			map->old_relfilenode,
			type_suffix,
			extent_suffix);
	snprintf(new_file, sizeof(new_file), "%s%s/%u/%u%s%s",
			map->new_tablespace,
			map->new_tablespace_suffix,
			map->new_db_oid,
			map->new_relfilenode,
			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 false;
			else
				pg_fatal("error while checking for file existence \"%s.%s\" (\"%s\" to \"%s\"): %s\n",
						map->nspname, map->relname, old_file, new_file,
						strerror(errno));
		}

		/* If file is empty, just return */
		if (statbuf.st_size == 0)
			return true;
	}

	unlink(new_file);

	/* Copying files might take some time, so give feedback. */
	pg_log(PG_STATUS, "%s", old_file);

	/* Rewrite visibility map if needed */
	if (vm_must_add_frozenbit && (strcmp(type_suffix, "_vm") == 0))
	{
		/* Need to rewrite visibility map format */
		pg_log(PG_VERBOSE, "rewriting \"%s\" to \"%s\"\n",
			   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\"\n",
					   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\"\n",
					   old_file, new_file);
				copyFile(old_file, new_file, map->nspname, map->relname);
				break;
			case TRANSFER_MODE_LINK:
				pg_log(PG_VERBOSE, "linking \"%s\" to \"%s\"\n",
					   old_file, new_file);
				linkFile(old_file, new_file, map->nspname, map->relname);
		}

	return true;
}

static void
transfer_ao(FileNameMap *map)
{
	transfer_relfile_segment(0, map, "", false);

	ao_foreach_extent_file(transfer_ao_perFile, map);
}

static bool
transfer_ao_perFile(const int segno, void *ctx)
{
	FileNameMap *map = ctx;

	if (!transfer_relfile_segment(segno, map , "", false))
		return false;

	return true;
}