Here's an updated version of pg_xlogdump.  This is rebased on top of the
committed xlogreader, palloc restructuring and libpgcommon, PG_RMGR
stuff, and is basically a revamped version of what Andres submitted in
http://www.postgresql.org/message-id/1357672187-7693-5-git-send-email-and...@2ndquadrant.com

I also attach a patch to move the relpathbackend() function to
src/common.  On top of that, it's trivial to change pg_xlogdump and
remove the "uninplemented" stub we're currently using.  (I also tried it
with a real implementation of relpath() that was mostly a duplicate of
the backend's relpath(), but I didn't like the duplication at all even
though I stripped the unnecessary bits).

(The more adventorous might think about moving timestamp_to_str to
src/common, as well, but this isn't a simple task: it depends on some
backend global state variables such as GUC vars, so it requires detailed
surgery.  I think it's a worthy goal nonetheless, because it'd allow us
to reduce useless duplication in ECPG, but it's not a 9.3 project)

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
*** /dev/null
--- b/contrib/pg_xlogdump/Makefile
***************
*** 0 ****
--- 1,32 ----
+ # contrib/pg_xlogdump/Makefile
+ 
+ PGFILEDESC = "pg_xlogdump"
+ PGAPPICON=win32
+ 
+ PROGRAM = pg_xlogdump
+ OBJS = pg_xlogdump.o compat.o xlogreader.o rmgrdesc.o \
+ 	$(RMGRDESCOBJS) $(WIN32RES)
+ 
+ RMGRDESCSOURCES = $(notdir $(wildcard $(top_srcdir)/src/backend/access/rmgrdesc/*desc.c))
+ RMGRDESCOBJS = $(patsubst %.c,%.o,$(RMGRDESCSOURCES))
+ 
+ EXTRA_CLEAN = $(RMGRDESCSOURCES) xlogreader.c rmgrdesc.c
+ 
+ ifdef USE_PGXS
+ PG_CONFIG = pg_config
+ PGXS := $(shell $(PG_CONFIG) --pgxs)
+ include $(PGXS)
+ else
+ subdir = contrib/pg_xlogdump
+ top_builddir = ../..
+ include $(top_builddir)/src/Makefile.global
+ include $(top_srcdir)/contrib/contrib-global.mk
+ endif
+ 
+ override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
+ 
+ rmgrdesc.c xlogreader.c: % : $(top_srcdir)/src/backend/access/transam/%
+ 	rm -f $@ && $(LN_S) $< .
+ 
+ $(RMGRDESCSOURCES): % : $(top_srcdir)/src/backend/access/rmgrdesc/%
+ 	rm -f $@ && $(LN_S) $< .
*** /dev/null
--- b/contrib/pg_xlogdump/compat.c
***************
*** 0 ****
--- 1,83 ----
+ /*-------------------------------------------------------------------------
+  *
+  * compat.c
+  *		Reimplementations of various backend functions.
+  *
+  * Portions Copyright (c) 2012, PostgreSQL Global Development Group
+  *
+  * IDENTIFICATION
+  *		contrib/pg_xlogdump/compat.c
+  *
+  * This file contains client-side implementations for various backend
+  * functions that the rm_desc functions in *desc.c files rely on.
+  *
+  *-------------------------------------------------------------------------
+  */
+ 
+ /* ugly hack, same as in e.g pg_controldata */
+ #define FRONTEND 1
+ #include "postgres.h"
+ 
+ #include "catalog/catalog.h"
+ #include "catalog/pg_tablespace.h"
+ #include "common/fe_memutils.h"
+ #include "datatype/timestamp.h"
+ #include "lib/stringinfo.h"
+ #include "storage/relfilenode.h"
+ 
+ const char *
+ timestamptz_to_str(TimestampTz dt)
+ {
+ 	return "unimplemented-timestamp";
+ }
+ 
+ /*
+  * Table of fork names.
+  *
+  * needs to be synced with src/backend/catalog/catalog.c
+  */
+ const char *forkNames[] = {
+ 	"main",						/* MAIN_FORKNUM */
+ 	"fsm",						/* FSM_FORKNUM */
+ 	"vm",						/* VISIBILITYMAP_FORKNUM */
+ 	"init"						/* INIT_FORKNUM */
+ };
+ #define FORKNAMECHARS	4
+ 
+ /*
+  * relpathbackend
+  *
+  * A pg_xlogdump implementation of the backend function of the same name.
+  * This one doesn't accept non-permanent relfilenodes.
+  */
+ char *
+ relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
+ {
+ 	return pg_strdup("unimplemented-relpath");
+ }
+ 
+ /*
+  * Provide a hacked up compat layer for StringInfos so xlog desc functions can
+  * be linked/called.
+  */
+ void
+ appendStringInfo(StringInfo str, const char *fmt, ...)
+ {
+ 	va_list		args;
+ 
+ 	va_start(args, fmt);
+ 	vprintf(fmt, args);
+ 	va_end(args);
+ }
+ 
+ void
+ appendStringInfoString(StringInfo str, const char *string)
+ {
+ 	appendStringInfo(str, "%s", string);
+ }
+ 
+ void
+ appendStringInfoChar(StringInfo str, char ch)
+ {
+ 	appendStringInfo(str, "%c", ch);
+ }
*** /dev/null
--- b/contrib/pg_xlogdump/pg_xlogdump.c
***************
*** 0 ****
--- 1,674 ----
+ /*-------------------------------------------------------------------------
+  *
+  * pg_xlogdump.c - decode and display WAL
+  *
+  * Copyright (c) 2012, PostgreSQL Global Development Group
+  *
+  * IDENTIFICATION
+  *		  contrib/pg_xlogdump/pg_xlogdump.c
+  *-------------------------------------------------------------------------
+  */
+ 
+ #define FRONTEND 1
+ #include "postgres.h"
+ 
+ #include <unistd.h>
+ 
+ #include "rmgrdesc.h"
+ 
+ #include "access/xlog.h"
+ #include "access/xlogreader.h"
+ #include "access/transam.h"
+ #include "catalog/catalog.h"
+ #include "common/fe_memutils.h"
+ #include "getopt_long.h"
+ 
+ 
+ static const char *progname;
+ 
+ typedef struct XLogDumpPrivateData
+ {
+ 	TimeLineID	timeline;
+ 	char	   *inpath;
+ 	XLogRecPtr	startptr;
+ 	XLogRecPtr	endptr;
+ 
+ 	/* display options */
+ 	bool		bkp_details;
+ 	int			stop_after_records;
+ 	int			already_displayed_records;
+ 
+ 	/* filter options */
+ 	int			filter_by_rmgr;
+ 	TransactionId filter_by_xid;
+ }	XLogDumpPrivateData;
+ 
+ static void
+ fatal_error(const char *fmt,...)
+ __attribute__((format(PG_PRINTF_ATTRIBUTE, 1, 2)));
+ 
+ static void
+ fatal_error(const char *fmt,...)
+ {
+ 	va_list		args;
+ 
+ 	fflush(stdout);
+ 
+ 	fprintf(stderr, "%s: FATAL:  ", progname);
+ 	va_start(args, fmt);
+ 	vfprintf(stderr, fmt, args);
+ 	va_end(args);
+ 	fputc('\n', stderr);
+ 
+ 	exit(EXIT_FAILURE);
+ }
+ 
+ /*
+  * Check whether directory exists and whether we can open it.
+  * errno is kept set so that the caller can report errors.
+  */
+ static bool
+ verify_directory(const char *directory)
+ {
+ 	int			fd = open(directory, O_DIRECTORY | O_RDONLY);
+ 
+ 	if (fd < 0)
+ 		return false;
+ 
+ 	close(fd);
+ 	errno = 0;					/* ignore errors in this case */
+ 	return true;
+ }
+ 
+ /*
+  * Split a pathname as dirname(1) and basename(1) would.
+  *
+  * XXX this probably doesn't do very well on Windows.  We probably need to
+  * apply canonicalize_path(), at the very least.
+  */
+ static void
+ split_path(const char *path, char **dir, char **fname)
+ {
+ 	char	   *sep;
+ 
+ 	/* split filepath into directory & filename */
+ 	sep = strrchr(path, '/');
+ 
+ 	/* directory path */
+ 	if (sep != NULL)
+ 	{
+ 		*dir = pg_strdup(path);
+ 		(*dir)[(sep - path) + 1] = '\0';	/* no strndup */
+ 		*fname = pg_strdup(sep + 1);
+ 	}
+ 	/* local directory */
+ 	else
+ 	{
+ 		*dir = NULL;
+ 		*fname = pg_strdup(path);
+ 	}
+ }
+ 
+ /*
+  * Try to find the file in several places:
+  * if directory == NULL:
+  *	 fname
+  *	 XLOGDIR / fname
+  *	 $PGDATA / XLOGDIR / fname
+  * else
+  *	 directory / fname
+  *	 directory / XLOGDIR / fname
+  *
+  * return a read only fd
+  */
+ static int
+ fuzzy_open_file(const char *directory, const char *fname)
+ {
+ 	int			fd = -1;
+ 	char		fpath[MAXPGPATH];
+ 
+ 	if (directory == NULL)
+ 	{
+ 		const char *datadir;
+ 
+ 		/* fname */
+ 		fd = open(fname, O_RDONLY | PG_BINARY, 0);
+ 		if (fd < 0 && errno != ENOENT)
+ 			return -1;
+ 		else if (fd > 0)
+ 			return fd;
+ 
+ 		/* XLOGDIR / fname */
+ 		snprintf(fpath, MAXPGPATH, "%s/%s",
+ 				 XLOGDIR, fname);
+ 		fd = open(fpath, O_RDONLY | PG_BINARY, 0);
+ 		if (fd < 0 && errno != ENOENT)
+ 			return -1;
+ 		else if (fd > 0)
+ 			return fd;
+ 
+ 		datadir = getenv("PGDATA");
+ 		/* $PGDATA / XLOGDIR / fname */
+ 		if (datadir != NULL)
+ 		{
+ 			snprintf(fpath, MAXPGPATH, "%s/%s/%s",
+ 					 datadir, XLOGDIR, fname);
+ 			fd = open(fpath, O_RDONLY | PG_BINARY, 0);
+ 			if (fd < 0 && errno != ENOENT)
+ 				return -1;
+ 			else if (fd > 0)
+ 				return fd;
+ 		}
+ 	}
+ 	else
+ 	{
+ 		/* directory / fname */
+ 		snprintf(fpath, MAXPGPATH, "%s/%s",
+ 				 directory, fname);
+ 		fd = open(fpath, O_RDONLY | PG_BINARY, 0);
+ 		if (fd < 0 && errno != ENOENT)
+ 			return -1;
+ 		else if (fd > 0)
+ 			return fd;
+ 
+ 		/* directory / XLOGDIR / fname */
+ 		snprintf(fpath, MAXPGPATH, "%s/%s/%s",
+ 				 directory, XLOGDIR, fname);
+ 		fd = open(fpath, O_RDONLY | PG_BINARY, 0);
+ 		if (fd < 0 && errno != ENOENT)
+ 			return -1;
+ 		else if (fd > 0)
+ 			return fd;
+ 	}
+ 	return -1;
+ }
+ 
+ /* this should probably be put in a general implementation */
+ static void
+ XLogDumpXLogRead(const char *directory, TimeLineID timeline_id,
+ 				 XLogRecPtr startptr, char *buf, Size count)
+ {
+ 	char	   *p;
+ 	XLogRecPtr	recptr;
+ 	Size		nbytes;
+ 
+ 	static int	sendFile = -1;
+ 	static XLogSegNo sendSegNo = 0;
+ 	static uint32 sendOff = 0;
+ 
+ 	p = buf;
+ 	recptr = startptr;
+ 	nbytes = count;
+ 
+ 	while (nbytes > 0)
+ 	{
+ 		uint32		startoff;
+ 		int			segbytes;
+ 		int			readbytes;
+ 
+ 		startoff = recptr % XLogSegSize;
+ 
+ 		if (sendFile < 0 || !XLByteInSeg(recptr, sendSegNo))
+ 		{
+ 			char		fname[MAXFNAMELEN];
+ 
+ 			/* Switch to another logfile segment */
+ 			if (sendFile >= 0)
+ 				close(sendFile);
+ 
+ 			XLByteToSeg(recptr, sendSegNo);
+ 
+ 			XLogFileName(fname, timeline_id, sendSegNo);
+ 
+ 			sendFile = fuzzy_open_file(directory, fname);
+ 
+ 			if (sendFile < 0)
+ 				fatal_error("could not find file \"%s\": %s",
+ 							fname, strerror(errno));
+ 			sendOff = 0;
+ 		}
+ 
+ 		/* Need to seek in the file? */
+ 		if (sendOff != startoff)
+ 		{
+ 			if (lseek(sendFile, (off_t) startoff, SEEK_SET) < 0)
+ 			{
+ 				int			err = errno;
+ 				char		fname[MAXPGPATH];
+ 
+ 				XLogFileName(fname, timeline_id, sendSegNo);
+ 
+ 				fatal_error("could not seek in log segment %s to offset %u: %s",
+ 							fname, startoff, strerror(err));
+ 			}
+ 			sendOff = startoff;
+ 		}
+ 
+ 		/* How many bytes are within this segment? */
+ 		if (nbytes > (XLogSegSize - startoff))
+ 			segbytes = XLogSegSize - startoff;
+ 		else
+ 			segbytes = nbytes;
+ 
+ 		readbytes = read(sendFile, p, segbytes);
+ 		if (readbytes <= 0)
+ 		{
+ 			int			err = errno;
+ 			char		fname[MAXPGPATH];
+ 
+ 			XLogFileName(fname, timeline_id, sendSegNo);
+ 
+ 			fatal_error("could not read from log segment %s, offset %d, length %d: %s",
+ 						fname, sendOff, segbytes, strerror(err));
+ 		}
+ 
+ 		/* Update state for read */
+ 		recptr += readbytes;
+ 
+ 		sendOff += readbytes;
+ 		nbytes -= readbytes;
+ 		p += readbytes;
+ 	}
+ }
+ 
+ static int
+ XLogDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen,
+ 				 XLogRecPtr targetPtr, char *readBuff, TimeLineID *curFileTLI)
+ {
+ 	XLogDumpPrivateData *private = state->private_data;
+ 	int			count = XLOG_BLCKSZ;
+ 
+ 	if (private->endptr != InvalidXLogRecPtr)
+ 	{
+ 		if (targetPagePtr + XLOG_BLCKSZ <= private->endptr)
+ 			count = XLOG_BLCKSZ;
+ 		else if (targetPagePtr + reqLen <= private->endptr)
+ 			count = private->endptr - targetPagePtr;
+ 		else
+ 			return -1;
+ 	}
+ 
+ 	XLogDumpXLogRead(private->inpath, private->timeline, targetPagePtr,
+ 					 readBuff, count);
+ 
+ 	return count;
+ }
+ 
+ static void
+ XLogDumpDisplayRecord(XLogReaderState *state, XLogRecord *record)
+ {
+ 	XLogDumpPrivateData *config = (XLogDumpPrivateData *) state->private_data;
+ 	const RmgrDescData *desc = &RmgrDescTable[record->xl_rmid];
+ 
+ 	if (config->filter_by_rmgr != -1 &&
+ 		config->filter_by_rmgr != record->xl_rmid)
+ 		return;
+ 
+ 	if (TransactionIdIsValid(config->filter_by_xid) &&
+ 		config->filter_by_xid != record->xl_xid)
+ 		return;
+ 
+ 	config->already_displayed_records++;
+ 
+ 	printf("xlog record: rmgr: %-11s, record_len: %6u, tot_len: %6u, tx: %10u, lsn: %X/%08X, prev %X/%08X, bkp: %u%u%u%u, desc:",
+ 		   desc->rm_name,
+ 		   record->xl_len, record->xl_tot_len,
+ 		   record->xl_xid,
+ 		   (uint32) (state->ReadRecPtr >> 32), (uint32) state->ReadRecPtr,
+ 		   (uint32) (record->xl_prev >> 32), (uint32) record->xl_prev,
+ 		   !!(XLR_BKP_BLOCK(0) & record->xl_info),
+ 		   !!(XLR_BKP_BLOCK(1) & record->xl_info),
+ 		   !!(XLR_BKP_BLOCK(2) & record->xl_info),
+ 		   !!(XLR_BKP_BLOCK(3) & record->xl_info));
+ 
+ 	/* the desc routine will printf the description directly to stdout */
+ 	desc->rm_desc(NULL, record->xl_info, XLogRecGetData(record));
+ 
+ 	putchar('\n');
+ 
+ 	if (config->bkp_details)
+ 	{
+ 		int			bkpnum;
+ 		char	   *blk = (char *) XLogRecGetData(record) + record->xl_len;
+ 
+ 		for (bkpnum = 0; bkpnum < XLR_MAX_BKP_BLOCKS; bkpnum++)
+ 		{
+ 			BkpBlock	bkpb;
+ 
+ 			if (!(XLR_BKP_BLOCK(bkpnum) & record->xl_info))
+ 				continue;
+ 
+ 			memcpy(&bkpb, blk, sizeof(BkpBlock));
+ 			blk += sizeof(BkpBlock);
+ 			blk += BLCKSZ - bkpb.hole_length;
+ 
+ 			printf("\tbackup bkp #%u; rel %u/%u/%u; fork: %s; block: %u; hole: offset: %u, length: %u\n",
+ 				   bkpnum,
+ 				   bkpb.node.spcNode, bkpb.node.dbNode, bkpb.node.relNode,
+ 				   forkNames[bkpb.fork],
+ 				   bkpb.block, bkpb.hole_offset, bkpb.hole_length);
+ 		}
+ 	}
+ }
+ 
+ static void
+ usage(void)
+ {
+ 	printf("%s decodes and displays PostgreSQL transaction logs for debugging.\n\n",
+ 		   progname);
+ 	printf("Usage:\n");
+ 	printf("  %s [OPTION] [STARTSEG [ENDSEG]] \n", progname);
+ 	printf("\nGeneral options:\n");
+ 	printf("  -V, --version          output version information, then exit\n");
+ 	printf("  -?, --help             show this help, then exit\n");
+ 	printf("\nContent options:\n");
+ 	printf("  -b, --bkp-details      output detailed information about backup blocks\n");
+ 	printf("  -e, --end=RECPTR       stop reading at log position RECPTR\n");
+ 	printf("  -n, --limit=N          number of records to display");
+ 	printf("  -p, --path=PATH        directory in which to find log segment files\n");
+ 	printf("                         (default: ./pg_xlog)");
+ 	printf("  -r, --rmgr=RMGR        only show records generated by resource manager RMGR\n");
+ 	printf("  -s, --start=RECPTR     stop reading at log position RECPTR");
+ 	printf("  -t, --timeline=TLI     timeline from which to read log records (default: 1)\n");
+ 	printf("  -x, --xid=XID          only show records with TransactionId XID\n");
+ }
+ 
+ int
+ main(int argc, char **argv)
+ {
+ 	uint32		xlogid;
+ 	uint32		xrecoff;
+ 	XLogReaderState *xlogreader_state;
+ 	XLogDumpPrivateData private;
+ 	XLogRecord *record;
+ 	XLogRecPtr	first_record;
+ 	char	   *errormsg;
+ 
+ 	static struct option long_options[] = {
+ 		{"bkp-details", no_argument, NULL, 'b'},
+ 		{"end", required_argument, NULL, 'e'},
+ 		{"help", no_argument, NULL, '?'},
+ 		{"limit", required_argument, NULL, 'n'},
+ 		{"path", required_argument, NULL, 'p'},
+ 		{"rmgr", required_argument, NULL, 'r'},
+ 		{"start", required_argument, NULL, 's'},
+ 		{"timeline", required_argument, NULL, 't'},
+ 		{"xid", required_argument, NULL, 'x'},
+ 		{"version", no_argument, NULL, 'V'},
+ 		{NULL, 0, NULL, 0}
+ 	};
+ 
+ 	int			option;
+ 	int			optindex = 0;
+ 
+ 	progname = get_progname(argv[0]);
+ 
+ 	memset(&private, 0, sizeof(XLogDumpPrivateData));
+ 
+ 	private.timeline = 1;
+ 	private.bkp_details = false;
+ 	private.startptr = InvalidXLogRecPtr;
+ 	private.endptr = InvalidXLogRecPtr;
+ 	private.stop_after_records = -1;
+ 	private.already_displayed_records = 0;
+ 	private.filter_by_rmgr = -1;
+ 	private.filter_by_xid = InvalidTransactionId;
+ 
+ 	if (argc <= 1)
+ 	{
+ 		fprintf(stderr, "%s: no arguments specified\n", progname);
+ 		goto bad_argument;
+ 	}
+ 
+ 	while ((option = getopt_long(argc, argv, "be:?n:p:r:s:t:Vx:",
+ 								 long_options, &optindex)) != -1)
+ 	{
+ 		switch (option)
+ 		{
+ 			case 'b':
+ 				private.bkp_details = true;
+ 				break;
+ 			case 'e':
+ 				if (sscanf(optarg, "%X/%X", &xlogid, &xrecoff) != 2)
+ 				{
+ 					fprintf(stderr, "%s: could not parse end log position \"%s\"\n",
+ 							progname, optarg);
+ 					goto bad_argument;
+ 				}
+ 				private.endptr = (uint64) xlogid << 32 | xrecoff;
+ 				break;
+ 			case '?':
+ 				usage();
+ 				exit(EXIT_SUCCESS);
+ 				break;
+ 			case 'n':
+ 				if (sscanf(optarg, "%d", &private.stop_after_records) != 1)
+ 				{
+ 					fprintf(stderr, "%s: could not parse limit \"%s\"\n",
+ 							progname, optarg);
+ 					goto bad_argument;
+ 				}
+ 				break;
+ 			case 'p':
+ 				private.inpath = pg_strdup(optarg);
+ 				break;
+ 			case 'r':
+ 				{
+ 					int			i;
+ 
+ 					for (i = 0; i < RM_MAX_ID; i++)
+ 					{
+ 						if (strcmp(optarg, RmgrDescTable[i].rm_name) == 0)
+ 						{
+ 							private.filter_by_rmgr = i;
+ 							break;
+ 						}
+ 					}
+ 
+ 					if (private.filter_by_rmgr == -1)
+ 					{
+ 						fprintf(stderr, "%s: resource manager \"%s\" does not exist\n",
+ 								progname, optarg);
+ 						goto bad_argument;
+ 					}
+ 				}
+ 				break;
+ 			case 's':
+ 				if (sscanf(optarg, "%X/%X", &xlogid, &xrecoff) != 2)
+ 				{
+ 					fprintf(stderr, "%s: could not parse end log position \"%s\"\n",
+ 							progname, optarg);
+ 					goto bad_argument;
+ 				}
+ 				else
+ 					private.startptr = (uint64) xlogid << 32 | xrecoff;
+ 				break;
+ 			case 't':
+ 				if (sscanf(optarg, "%d", &private.timeline) != 1)
+ 				{
+ 					fprintf(stderr, "%s: could not parse timeline \"%s\"\n",
+ 							progname, optarg);
+ 					goto bad_argument;
+ 				}
+ 				break;
+ 			case 'V':
+ 				puts("pg_xlogdump (PostgreSQL) " PG_VERSION);
+ 				exit(EXIT_SUCCESS);
+ 				break;
+ 			case 'x':
+ 				if (sscanf(optarg, "%u", &private.filter_by_xid) != 1)
+ 				{
+ 					fprintf(stderr, "%s: could not parse \"%s\" as a valid xid\n",
+ 							progname, optarg);
+ 					goto bad_argument;
+ 				}
+ 				break;
+ 			default:
+ 				goto bad_argument;
+ 		}
+ 	}
+ 
+ 	if ((optind + 2) < argc)
+ 	{
+ 		fprintf(stderr,
+ 				"%s: too many command-line arguments (first is \"%s\")\n",
+ 				progname, argv[optind + 2]);
+ 		goto bad_argument;
+ 	}
+ 
+ 	if (private.inpath != NULL)
+ 	{
+ 		/* validate path points to directory */
+ 		if (!verify_directory(private.inpath))
+ 		{
+ 			fprintf(stderr,
+ 					"%s: path \"%s\" cannot be opened: %s",
+ 					progname, private.inpath, strerror(errno));
+ 			goto bad_argument;
+ 		}
+ 	}
+ 
+ 	/* parse files as start/end boundaries, extract path if not specified */
+ 	if (optind < argc)
+ 	{
+ 		char	   *directory = NULL;
+ 		char	   *fname = NULL;
+ 		int			fd;
+ 		XLogSegNo	segno;
+ 
+ 		split_path(argv[optind], &directory, &fname);
+ 
+ 		if (private.inpath == NULL && directory != NULL)
+ 		{
+ 			private.inpath = directory;
+ 
+ 			if (!verify_directory(private.inpath))
+ 				fatal_error("cannot open directory \"%s\": %s",
+ 							private.inpath, strerror(errno));
+ 		}
+ 
+ 		fd = fuzzy_open_file(private.inpath, fname);
+ 		if (fd < 0)
+ 			fatal_error("could not open file \"%s\"", fname);
+ 		close(fd);
+ 
+ 		/* parse position from file */
+ 		XLogFromFileName(fname, &private.timeline, &segno);
+ 
+ 		if (XLogRecPtrIsInvalid(private.startptr))
+ 			XLogSegNoOffsetToRecPtr(segno, 0, private.startptr);
+ 		else if (!XLByteInSeg(private.startptr, segno))
+ 		{
+ 			fprintf(stderr,
+ 					"%s: end log position %X/%X is not inside file \"%s\"\n",
+ 					progname,
+ 					(uint32) (private.startptr >> 32),
+ 					(uint32) private.startptr,
+ 					fname);
+ 			goto bad_argument;
+ 		}
+ 
+ 		/* no second file specified, set end position */
+ 		if (!(optind + 1 < argc) && XLogRecPtrIsInvalid(private.endptr))
+ 			XLogSegNoOffsetToRecPtr(segno + 1, 0, private.endptr);
+ 
+ 		/* parse ENDSEG if passed */
+ 		if (optind + 1 < argc)
+ 		{
+ 			XLogSegNo	endsegno;
+ 
+ 			/* ignore directory, already have that */
+ 			split_path(argv[optind + 1], &directory, &fname);
+ 
+ 			fd = fuzzy_open_file(private.inpath, fname);
+ 			if (fd < 0)
+ 				fatal_error("could not open file \"%s\"", fname);
+ 			close(fd);
+ 
+ 			/* parse position from file */
+ 			XLogFromFileName(fname, &private.timeline, &endsegno);
+ 
+ 			if (endsegno < segno)
+ 				fatal_error("ENDSEG %s is before STARTSEG %s",
+ 							argv[optind + 1], argv[optind]);
+ 
+ 			if (XLogRecPtrIsInvalid(private.endptr))
+ 				XLogSegNoOffsetToRecPtr(endsegno + 1, 0, private.endptr);
+ 
+ 			/* set segno to endsegno for check of --end */
+ 			segno = endsegno;
+ 		}
+ 
+ 
+ 		if (!XLByteInSeg(private.endptr, segno) &&
+ 			private.endptr != (segno + 1) * XLogSegSize)
+ 		{
+ 			fprintf(stderr,
+ 					"%s: end log position %X/%X is not inside file \"%s\"\n",
+ 					progname,
+ 					(uint32) (private.endptr >> 32),
+ 					(uint32) private.endptr,
+ 					argv[argc - 1]);
+ 			goto bad_argument;
+ 		}
+ 	}
+ 
+ 	/* we don't know what to print */
+ 	if (XLogRecPtrIsInvalid(private.startptr))
+ 	{
+ 		fprintf(stderr, "%s: no start log position given in range mode.\n", progname);
+ 		goto bad_argument;
+ 	}
+ 
+ 	/* done with argument parsing, do the actual work */
+ 
+ 	/* we have everything we need, start reading */
+ 	xlogreader_state = XLogReaderAllocate(XLogDumpReadPage, &private);
+ 	if (!xlogreader_state)
+ 		fatal_error("out of memory");
+ 
+ 	/* first find a valid recptr to start from */
+ 	first_record = XLogFindNextRecord(xlogreader_state, private.startptr);
+ 
+ 	if (first_record == InvalidXLogRecPtr)
+ 		fatal_error("could not find a valid record after %X/%X",
+ 					(uint32) (private.startptr >> 32),
+ 					(uint32) private.startptr);
+ 
+ 	/*
+ 	 * Display a message that we're skipping data if `from` wasn't a pointer to
+ 	 * the start of a record and also wasn't a pointer to the beginning of a
+ 	 * segment (e.g. we were used in file mode).
+ 	 */
+ 	if (first_record != private.startptr && (private.startptr % XLogSegSize) != 0)
+ 		printf("first record is after %X/%X, at %X/%X, skipping over %u bytes\n",
+ 			   (uint32) (private.startptr >> 32), (uint32) private.startptr,
+ 			   (uint32) (first_record >> 32), (uint32) first_record,
+ 			   (uint32) (first_record - private.startptr));
+ 
+ 	while ((record = XLogReadRecord(xlogreader_state, first_record, &errormsg)))
+ 	{
+ 		/* continue after the last record */
+ 		first_record = InvalidXLogRecPtr;
+ 		XLogDumpDisplayRecord(xlogreader_state, record);
+ 
+ 		/* check whether we printed enough */
+ 		if (private.stop_after_records > 0 &&
+ 			private.already_displayed_records >= private.stop_after_records)
+ 			break;
+ 	}
+ 
+ 	if (errormsg)
+ 		fatal_error("error in WAL record at %X/%X: %s\n",
+ 					(uint32) (xlogreader_state->ReadRecPtr >> 32),
+ 					(uint32) xlogreader_state->ReadRecPtr,
+ 					errormsg);
+ 
+ 	XLogReaderFree(xlogreader_state);
+ 
+ 	return EXIT_SUCCESS;
+ 
+ bad_argument:
+ 	fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
+ 	return EXIT_FAILURE;
+ }
*** /dev/null
--- b/contrib/pg_xlogdump/rmgrdesc.c
***************
*** 0 ****
--- 1,36 ----
+ /*
+  * rmgrdesc.c
+  *
+  * pg_xlogdump resource managers definition
+  *
+  * contrib/pg_xlogdump/rmgrdesc.c
+  */
+ #define FRONTEND 1
+ #include "postgres.h"
+ 
+ #include "access/clog.h"
+ #include "access/gin.h"
+ #include "access/gist_private.h"
+ #include "access/hash.h"
+ #include "access/heapam_xlog.h"
+ #include "access/multixact.h"
+ #include "access/nbtree.h"
+ #include "access/rmgr.h"
+ #include "access/spgist.h"
+ #include "access/xact.h"
+ #include "access/xlog_internal.h"
+ #include "catalog/storage_xlog.h"
+ #include "commands/dbcommands.h"
+ #include "commands/sequence.h"
+ #include "commands/tablespace.h"
+ #include "rmgrdesc.h"
+ #include "storage/standby.h"
+ #include "utils/relmapper.h"
+ 
+ #define PG_RMGR(symname,name,redo,desc,startup,cleanup,restartpoint) \
+ 	{ name, desc, },
+ 
+ const RmgrDescData RmgrDescTable[RM_MAX_ID + 1] = {
+ #include "access/rmgrlist.h"
+ };
+ 
*** /dev/null
--- b/contrib/pg_xlogdump/rmgrdesc.h
***************
*** 0 ****
--- 1,21 ----
+ /*
+  * rmgrdesc.h
+  *
+  * pg_xlogdump resource managers declaration
+  *
+  * contrib/pg_xlogdump/rmgrdesc.h
+  */
+ #ifndef RMGRDESC_H
+ #define RMGRDESC_H
+ 
+ #include "lib/stringinfo.h"
+ 
+ typedef struct RmgrDescData
+ {
+ 	const char *rm_name;
+ 	void	  (*rm_desc) (StringInfo buf, uint8 xl_info, char *rec);
+ } RmgrDescData;
+ 
+ extern const RmgrDescData RmgrDescTable[];
+ 
+ #endif /* RMGRDESC_H */
*** /dev/null
--- b/doc/src/sgml/ref/pg_xlogdump.sgml
***************
*** 0 ****
--- 1,76 ----
+ <!--
+ doc/src/sgml/ref/pg_xlogdump.sgml
+ PostgreSQL documentation
+ -->
+ 
+ <refentry id="APP-PGXLOGDUMP">
+  <refmeta>
+   <refentrytitle><application>pg_xlogdump</application></refentrytitle>
+   <manvolnum>1</manvolnum>
+   <refmiscinfo>Application</refmiscinfo>
+  </refmeta>
+ 
+  <refnamediv>
+   <refname>pg_xlogdump</refname>
+   <refpurpose>Display the write-ahead log of a <productname>PostgreSQL</productname> database cluster</refpurpose>
+  </refnamediv>
+ 
+  <indexterm zone="app-pgxlogdump">
+   <primary>pg_xlogdump</primary>
+  </indexterm>
+ 
+  <refsynopsisdiv>
+   <cmdsynopsis>
+    <command>pg_xlogdump</command>
+    <arg choice="opt"><option>-b</option></arg>
+    <arg choice="opt"><option>-e</option> <replaceable class="parameter">xlogrecptr</replaceable></arg>
+    <arg choice="opt"><option>-f</option> <replaceable class="parameter">filename</replaceable></arg>
+    <arg choice="opt"><option>-h</option></arg>
+    <arg choice="opt"><option>-p</option> <replaceable class="parameter">directory</replaceable></arg>
+    <arg choice="opt"><option>-s</option> <replaceable class="parameter">xlogrecptr</replaceable></arg>
+    <arg choice="opt"><option>-t</option> <replaceable class="parameter">timelineid</replaceable></arg>
+    <arg choice="opt"><option>-v</option></arg>
+   </cmdsynopsis>
+  </refsynopsisdiv>
+ 
+  <refsect1 id="R1-APP-PGXLOGDUMP-1">
+   <title>Description</title>
+   <para>
+    <command>pg_xlogdump</command> display the write-ahead log (WAL) and is only
+    useful for debugging or educational purposes.
+   </para>
+ 
+   <para>
+    This utility can only be run by the user who installed the server, because
+    it requires read access to the data directory. It does not perform any
+    modifications.
+   </para>
+  </refsect1>
+ 
+  <refsect1>
+   <title>Options</title>
+ 
+    <para>
+     The following command-line options control the location and format of the
+     output.
+ 
+     <variablelist>
+      <varlistentry>
+       <term><option>-p <replaceable class="parameter">directory</replaceable></option></term>
+       <listitem>
+        <para>
+         Directory to find xlog files in.
+        </para>
+       </listitem>
+      </varlistentry>
+     </variablelist>
+    </para>
+  </refsect1>
+ 
+  <refsect1>
+   <title>Notes</title>
+   <para>
+     Can give wrong results when the server is running.
+   </para>
+  </refsect1>
+ </refentry>
*** a/src/include/utils/palloc.h
--- b/src/include/utils/palloc.h
***************
*** 28,35 ****
  #ifndef PALLOC_H
  #define PALLOC_H
  
- #ifndef FRONTEND
- 
  /*
   * Type MemoryContextData is declared in nodes/memnodes.h.	Most users
   * of memory allocation should just treat it as an abstract type, so we
--- 28,33 ----
***************
*** 37,42 ****
--- 35,42 ----
   */
  typedef struct MemoryContextData *MemoryContext;
  
+ #ifndef FRONTEND
+ 
  /*
   * CurrentMemoryContext is the default allocation context for palloc().
   * We declare it here so that palloc() can be a macro.	Avoid accessing it
*** a/src/backend/access/rmgrdesc/smgrdesc.c
--- b/src/backend/access/rmgrdesc/smgrdesc.c
***************
*** 16,21 ****
--- 16,22 ----
  
  #include "catalog/catalog.h"
  #include "catalog/storage_xlog.h"
+ #include "common/relpath.h"
  
  
  void
*** a/src/backend/access/rmgrdesc/xactdesc.c
--- b/src/backend/access/rmgrdesc/xactdesc.c
***************
*** 16,21 ****
--- 16,22 ----
  
  #include "access/xact.h"
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "storage/sinval.h"
  #include "utils/timestamp.h"
  
*** a/src/backend/access/transam/xlogutils.c
--- b/src/backend/access/transam/xlogutils.c
***************
*** 20,25 ****
--- 20,26 ----
  #include "access/xlog.h"
  #include "access/xlogutils.h"
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "storage/smgr.h"
  #include "utils/guc.h"
  #include "utils/hsearch.h"
*** a/src/backend/catalog/catalog.c
--- b/src/backend/catalog/catalog.c
***************
*** 37,42 ****
--- 37,43 ----
  #include "catalog/pg_shseclabel.h"
  #include "catalog/pg_tablespace.h"
  #include "catalog/toasting.h"
+ #include "common/relpath.h"
  #include "miscadmin.h"
  #include "storage/fd.h"
  #include "utils/fmgroids.h"
***************
*** 44,64 ****
  #include "utils/tqual.h"
  
  
- #define FORKNAMECHARS	4		/* max chars for a fork name */
- 
- /*
-  * Lookup table of fork name by fork number.
-  *
-  * If you add a new entry, remember to update the errhint below, and the
-  * documentation for pg_relation_size(). Also keep FORKNAMECHARS above
-  * up-to-date.
-  */
- const char *forkNames[] = {
- 	"main",						/* MAIN_FORKNUM */
- 	"fsm",						/* FSM_FORKNUM */
- 	"vm",						/* VISIBILITYMAP_FORKNUM */
- 	"init"						/* INIT_FORKNUM */
- };
  
  /*
   * forkname_to_number - look up fork number by name
--- 45,50 ----
***************
*** 80,209 **** forkname_to_number(char *forkName)
  }
  
  /*
-  * forkname_chars
-  *		We use this to figure out whether a filename could be a relation
-  *		fork (as opposed to an oddly named stray file that somehow ended
-  *		up in the database directory).	If the passed string begins with
-  *		a fork name (other than the main fork name), we return its length,
-  *		and set *fork (if not NULL) to the fork number.  If not, we return 0.
-  *
-  * Note that the present coding assumes that there are no fork names which
-  * are prefixes of other fork names.
-  */
- int
- forkname_chars(const char *str, ForkNumber *fork)
- {
- 	ForkNumber	forkNum;
- 
- 	for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
- 	{
- 		int			len = strlen(forkNames[forkNum]);
- 
- 		if (strncmp(forkNames[forkNum], str, len) == 0)
- 		{
- 			if (fork)
- 				*fork = forkNum;
- 			return len;
- 		}
- 	}
- 	return 0;
- }
- 
- /*
-  * relpathbackend - construct path to a relation's file
-  *
-  * Result is a palloc'd string.
-  */
- char *
- relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
- {
- 	int			pathlen;
- 	char	   *path;
- 
- 	if (rnode.spcNode == GLOBALTABLESPACE_OID)
- 	{
- 		/* Shared system relations live in {datadir}/global */
- 		Assert(rnode.dbNode == 0);
- 		Assert(backend == InvalidBackendId);
- 		pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
- 		path = (char *) palloc(pathlen);
- 		if (forknum != MAIN_FORKNUM)
- 			snprintf(path, pathlen, "global/%u_%s",
- 					 rnode.relNode, forkNames[forknum]);
- 		else
- 			snprintf(path, pathlen, "global/%u", rnode.relNode);
- 	}
- 	else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
- 	{
- 		/* The default tablespace is {datadir}/base */
- 		if (backend == InvalidBackendId)
- 		{
- 			pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
- 			path = (char *) palloc(pathlen);
- 			if (forknum != MAIN_FORKNUM)
- 				snprintf(path, pathlen, "base/%u/%u_%s",
- 						 rnode.dbNode, rnode.relNode,
- 						 forkNames[forknum]);
- 			else
- 				snprintf(path, pathlen, "base/%u/%u",
- 						 rnode.dbNode, rnode.relNode);
- 		}
- 		else
- 		{
- 			/* OIDCHARS will suffice for an integer, too */
- 			pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
- 				+ FORKNAMECHARS + 1;
- 			path = (char *) palloc(pathlen);
- 			if (forknum != MAIN_FORKNUM)
- 				snprintf(path, pathlen, "base/%u/t%d_%u_%s",
- 						 rnode.dbNode, backend, rnode.relNode,
- 						 forkNames[forknum]);
- 			else
- 				snprintf(path, pathlen, "base/%u/t%d_%u",
- 						 rnode.dbNode, backend, rnode.relNode);
- 		}
- 	}
- 	else
- 	{
- 		/* All other tablespaces are accessed via symlinks */
- 		if (backend == InvalidBackendId)
- 		{
- 			pathlen = 9 + 1 + OIDCHARS + 1
- 				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
- 				+ OIDCHARS + 1 + FORKNAMECHARS + 1;
- 			path = (char *) palloc(pathlen);
- 			if (forknum != MAIN_FORKNUM)
- 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
- 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
- 						 rnode.dbNode, rnode.relNode,
- 						 forkNames[forknum]);
- 			else
- 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
- 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
- 						 rnode.dbNode, rnode.relNode);
- 		}
- 		else
- 		{
- 			/* OIDCHARS will suffice for an integer, too */
- 			pathlen = 9 + 1 + OIDCHARS + 1
- 				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
- 				+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
- 			path = (char *) palloc(pathlen);
- 			if (forknum != MAIN_FORKNUM)
- 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
- 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
- 						 rnode.dbNode, backend, rnode.relNode,
- 						 forkNames[forknum]);
- 			else
- 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
- 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
- 						 rnode.dbNode, backend, rnode.relNode);
- 		}
- 	}
- 	return path;
- }
- 
- /*
   * GetDatabasePath			- construct path to a database dir
   *
   * Result is a palloc'd string.
--- 66,71 ----
*** a/src/backend/commands/tablespace.c
--- b/src/backend/commands/tablespace.c
***************
*** 64,69 ****
--- 64,70 ----
  #include "commands/comment.h"
  #include "commands/seclabel.h"
  #include "commands/tablespace.h"
+ #include "common/relpath.h"
  #include "miscadmin.h"
  #include "postmaster/bgwriter.h"
  #include "storage/fd.h"
*** a/src/backend/storage/buffer/bufmgr.c
--- b/src/backend/storage/buffer/bufmgr.c
***************
*** 34,39 ****
--- 34,40 ----
  #include <unistd.h>
  
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "executor/instrument.h"
  #include "miscadmin.h"
  #include "pg_trace.h"
*** a/src/backend/storage/buffer/localbuf.c
--- b/src/backend/storage/buffer/localbuf.c
***************
*** 16,21 ****
--- 16,22 ----
  #include "postgres.h"
  
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "executor/instrument.h"
  #include "storage/buf_internals.h"
  #include "storage/bufmgr.h"
*** a/src/backend/storage/file/fd.c
--- b/src/backend/storage/file/fd.c
***************
*** 71,76 ****
--- 71,77 ----
  #include "access/xact.h"
  #include "catalog/catalog.h"
  #include "catalog/pg_tablespace.h"
+ #include "common/relpath.h"
  #include "pgstat.h"
  #include "storage/fd.h"
  #include "storage/ipc.h"
*** a/src/backend/storage/file/reinit.c
--- b/src/backend/storage/file/reinit.c
***************
*** 17,22 ****
--- 17,23 ----
  #include <unistd.h>
  
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "storage/copydir.h"
  #include "storage/fd.h"
  #include "storage/reinit.h"
*** a/src/backend/storage/smgr/md.c
--- b/src/backend/storage/smgr/md.c
***************
*** 21,26 ****
--- 21,27 ----
  #include "miscadmin.h"
  #include "access/xlog.h"
  #include "catalog/catalog.h"
+ #include "common/relpath.h"
  #include "portability/instr_time.h"
  #include "postmaster/bgwriter.h"
  #include "storage/fd.h"
*** a/src/backend/utils/adt/dbsize.c
--- b/src/backend/utils/adt/dbsize.c
***************
*** 21,26 ****
--- 21,27 ----
  #include "catalog/pg_tablespace.h"
  #include "commands/dbcommands.h"
  #include "commands/tablespace.h"
+ #include "common/relpath.h"
  #include "miscadmin.h"
  #include "storage/fd.h"
  #include "utils/acl.h"
*** a/src/backend/utils/adt/misc.c
--- b/src/backend/utils/adt/misc.c
***************
*** 24,29 ****
--- 24,30 ----
  #include "catalog/pg_tablespace.h"
  #include "catalog/pg_type.h"
  #include "commands/dbcommands.h"
+ #include "common/relpath.h"
  #include "funcapi.h"
  #include "miscadmin.h"
  #include "parser/keywords.h"
*** a/src/backend/utils/cache/relcache.c
--- b/src/backend/utils/cache/relcache.c
***************
*** 56,61 ****
--- 56,62 ----
  #include "catalog/schemapg.h"
  #include "catalog/storage.h"
  #include "commands/trigger.h"
+ #include "common/relpath.h"
  #include "miscadmin.h"
  #include "optimizer/clauses.h"
  #include "optimizer/planmain.h"
*** a/src/common/Makefile
--- b/src/common/Makefile
***************
*** 23,29 **** include $(top_builddir)/src/Makefile.global
  override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
  LIBS += $(PTHREAD_LIBS)
  
! OBJS_COMMON =
  
  OBJS_FRONTEND = $(OBJS_COMMON) fe_memutils.o
  
--- 23,29 ----
  override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
  LIBS += $(PTHREAD_LIBS)
  
! OBJS_COMMON = relpath.o
  
  OBJS_FRONTEND = $(OBJS_COMMON) fe_memutils.o
  
*** /dev/null
--- b/src/common/relpath.c
***************
*** 0 ****
--- 1,150 ----
+ #ifndef FRONTEND
+ #include "postgres.h"
+ #else
+ #include "postgres_fe.h"
+ #endif
+ 
+ #include "catalog/pg_tablespace.h"
+ #include "common/relpath.h"
+ #include "storage/backendid.h"
+ 
+ #define FORKNAMECHARS	4		/* max chars for a fork name */
+ 
+ /*
+  * Lookup table of fork name by fork number.
+  *
+  * If you add a new entry, remember to update the errhint below, and the
+  * documentation for pg_relation_size(). Also keep FORKNAMECHARS above
+  * up-to-date.
+  */
+ const char *forkNames[] = {
+ 	"main",						/* MAIN_FORKNUM */
+ 	"fsm",						/* FSM_FORKNUM */
+ 	"vm",						/* VISIBILITYMAP_FORKNUM */
+ 	"init"						/* INIT_FORKNUM */
+ };
+ 
+ /*
+  * forkname_chars
+  *		We use this to figure out whether a filename could be a relation
+  *		fork (as opposed to an oddly named stray file that somehow ended
+  *		up in the database directory).	If the passed string begins with
+  *		a fork name (other than the main fork name), we return its length,
+  *		and set *fork (if not NULL) to the fork number.  If not, we return 0.
+  *
+  * Note that the present coding assumes that there are no fork names which
+  * are prefixes of other fork names.
+  */
+ int
+ forkname_chars(const char *str, ForkNumber *fork)
+ {
+ 	ForkNumber	forkNum;
+ 
+ 	for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
+ 	{
+ 		int			len = strlen(forkNames[forkNum]);
+ 
+ 		if (strncmp(forkNames[forkNum], str, len) == 0)
+ 		{
+ 			if (fork)
+ 				*fork = forkNum;
+ 			return len;
+ 		}
+ 	}
+ 	return 0;
+ }
+ 
+ /*
+  * relpathbackend - construct path to a relation's file
+  *
+  * Result is a palloc'd string.
+  */
+ char *
+ relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
+ {
+ 	int			pathlen;
+ 	char	   *path;
+ 
+ 	if (rnode.spcNode == GLOBALTABLESPACE_OID)
+ 	{
+ 		/* Shared system relations live in {datadir}/global */
+ 		Assert(rnode.dbNode == 0);
+ 		Assert(backend == InvalidBackendId);
+ 		pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+ 		path = (char *) palloc(pathlen);
+ 		if (forknum != MAIN_FORKNUM)
+ 			snprintf(path, pathlen, "global/%u_%s",
+ 					 rnode.relNode, forkNames[forknum]);
+ 		else
+ 			snprintf(path, pathlen, "global/%u", rnode.relNode);
+ 	}
+ 	else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
+ 	{
+ 		/* The default tablespace is {datadir}/base */
+ 		if (backend == InvalidBackendId)
+ 		{
+ 			pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+ 			path = (char *) palloc(pathlen);
+ 			if (forknum != MAIN_FORKNUM)
+ 				snprintf(path, pathlen, "base/%u/%u_%s",
+ 						 rnode.dbNode, rnode.relNode,
+ 						 forkNames[forknum]);
+ 			else
+ 				snprintf(path, pathlen, "base/%u/%u",
+ 						 rnode.dbNode, rnode.relNode);
+ 		}
+ 		else
+ 		{
+ 			/* OIDCHARS will suffice for an integer, too */
+ 			pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
+ 				+ FORKNAMECHARS + 1;
+ 			path = (char *) palloc(pathlen);
+ 			if (forknum != MAIN_FORKNUM)
+ 				snprintf(path, pathlen, "base/%u/t%d_%u_%s",
+ 						 rnode.dbNode, backend, rnode.relNode,
+ 						 forkNames[forknum]);
+ 			else
+ 				snprintf(path, pathlen, "base/%u/t%d_%u",
+ 						 rnode.dbNode, backend, rnode.relNode);
+ 		}
+ 	}
+ 	else
+ 	{
+ 		/* All other tablespaces are accessed via symlinks */
+ 		if (backend == InvalidBackendId)
+ 		{
+ 			pathlen = 9 + 1 + OIDCHARS + 1
+ 				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
+ 				+ OIDCHARS + 1 + FORKNAMECHARS + 1;
+ 			path = (char *) palloc(pathlen);
+ 			if (forknum != MAIN_FORKNUM)
+ 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
+ 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+ 						 rnode.dbNode, rnode.relNode,
+ 						 forkNames[forknum]);
+ 			else
+ 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
+ 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+ 						 rnode.dbNode, rnode.relNode);
+ 		}
+ 		else
+ 		{
+ 			/* OIDCHARS will suffice for an integer, too */
+ 			pathlen = 9 + 1 + OIDCHARS + 1
+ 				+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
+ 				+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+ 			path = (char *) palloc(pathlen);
+ 			if (forknum != MAIN_FORKNUM)
+ 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
+ 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+ 						 rnode.dbNode, backend, rnode.relNode,
+ 						 forkNames[forknum]);
+ 			else
+ 				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
+ 						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+ 						 rnode.dbNode, backend, rnode.relNode);
+ 		}
+ 	}
+ 	return path;
+ }
+ 
*** a/src/include/catalog/catalog.h
--- b/src/include/catalog/catalog.h
***************
*** 14,47 ****
  #ifndef CATALOG_H
  #define CATALOG_H
  
- /*
-  *	'pgrminclude ignore' needed here because CppAsString2() does not throw
-  *	an error if the symbol is not defined.
-  */
- #include "catalog/catversion.h" /* pgrminclude ignore */
  #include "catalog/pg_class.h"
  #include "storage/relfilenode.h"
  #include "utils/relcache.h"
  
- #define OIDCHARS		10		/* max chars printed by %u */
- #define TABLESPACE_VERSION_DIRECTORY	"PG_" PG_MAJORVERSION "_" \
- 									CppAsString2(CATALOG_VERSION_NO)
- 
- extern const char *forkNames[];
  extern ForkNumber forkname_to_number(char *forkName);
- extern int	forkname_chars(const char *str, ForkNumber *);
  
- extern char *relpathbackend(RelFileNode rnode, BackendId backend,
- 			   ForkNumber forknum);
  extern char *GetDatabasePath(Oid dbNode, Oid spcNode);
  
- /* First argument is a RelFileNodeBackend */
- #define relpath(rnode, forknum) \
- 		relpathbackend((rnode).node, (rnode).backend, (forknum))
- 
- /* First argument is a RelFileNode */
- #define relpathperm(rnode, forknum) \
- 		relpathbackend((rnode), InvalidBackendId, (forknum))
  
  extern bool IsSystemRelation(Relation relation);
  extern bool IsToastRelation(Relation relation);
--- 14,27 ----
*** /dev/null
--- b/src/include/common/relpath.h
***************
*** 0 ****
--- 1,28 ----
+ #ifndef COMMON_RELPATH_H
+ #define COMMON_RELPATH_H
+ 
+ /*
+  *	'pgrminclude ignore' needed here because CppAsString2() does not throw
+  *	an error if the symbol is not defined.
+  */
+ #include "catalog/catversion.h" /* pgrminclude ignore */
+ #include "storage/relfilenode.h"
+ 
+ #define OIDCHARS		10		/* max chars printed by %u */
+ #define TABLESPACE_VERSION_DIRECTORY	"PG_" PG_MAJORVERSION "_" \
+ 									CppAsString2(CATALOG_VERSION_NO)
+ 
+ extern const char *forkNames[];
+ extern int	forkname_chars(const char *str, ForkNumber *);
+ extern char *relpathbackend(RelFileNode rnode, BackendId backend,
+ 			   ForkNumber forknum);
+ 
+ /* First argument is a RelFileNodeBackend */
+ #define relpath(rnode, forknum) \
+ 		relpathbackend((rnode).node, (rnode).backend, (forknum))
+ 
+ /* First argument is a RelFileNode */
+ #define relpathperm(rnode, forknum) \
+ 		relpathbackend((rnode), InvalidBackendId, (forknum))
+ 
+ #endif
-- 
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