mirror of https://github.com/postgres/postgres
This can dump the contents of the WAL summary files found in pg_wal/summaries. Normally, this shouldn't really be something anyone needs to do, but it may be needed for debugging problems with incremental backup, or could possibly be useful to external tools. Discussion: http://postgr.es/m/CA+Tgmobvqqj-DW9F7uUzT-cQqs6wcVb-Xhs=w=hzJnXSE-kRGw@mail.gmail.compull/152/head
Robert Haas
2 years ago
parent
d9ef650fca
commit
ee1bfd1683
@ -0,0 +1,122 @@ |
||||
<!-- |
||||
doc/src/sgml/ref/pg_walsummary.sgml |
||||
PostgreSQL documentation |
||||
--> |
||||
|
||||
<refentry id="app-pgwalsummary"> |
||||
<indexterm zone="app-pgwalsummary"> |
||||
<primary>pg_walsummary</primary> |
||||
</indexterm> |
||||
|
||||
<refmeta> |
||||
<refentrytitle><application>pg_walsummary</application></refentrytitle> |
||||
<manvolnum>1</manvolnum> |
||||
<refmiscinfo>Application</refmiscinfo> |
||||
</refmeta> |
||||
|
||||
<refnamediv> |
||||
<refname>pg_walsummary</refname> |
||||
<refpurpose>print contents of WAL summary files</refpurpose> |
||||
</refnamediv> |
||||
|
||||
<refsynopsisdiv> |
||||
<cmdsynopsis> |
||||
<command>pg_walsummary</command> |
||||
<arg rep="repeat" choice="opt"><replaceable>option</replaceable></arg> |
||||
<arg rep="repeat"><replaceable>file</replaceable></arg> |
||||
</cmdsynopsis> |
||||
</refsynopsisdiv> |
||||
|
||||
<refsect1> |
||||
<title>Description</title> |
||||
<para> |
||||
<application>pg_walsummary</application> is used to print the contents of |
||||
WAL summary files. These binary files are found with the |
||||
<literal>pg_wal/summaries</literal> subdirectory of the data directory, |
||||
and can be converted to text using this tool. This is not ordinarily |
||||
necessary, since WAL summary files primarily exist to support |
||||
<link linkend="backup-incremental-backup">incremental backup</link>, |
||||
but it may be useful for debugging purposes. |
||||
</para> |
||||
|
||||
<para> |
||||
A WAL summary file is indexed by tablespace OID, relation OID, and relation |
||||
fork. For each relation fork, it stores the list of blocks that were |
||||
modified by WAL within the range summarized in the file. It can also |
||||
store a "limit block," which is 0 if the relation fork was created or |
||||
truncated within the relevant WAL range, and otherwise the shortest length |
||||
to which the relation fork was truncated. If the relation fork was not |
||||
created, deleted, or truncated within the relevant WAL range, the limit |
||||
block is undefined or infinite and will not be printed by this tool. |
||||
</para> |
||||
</refsect1> |
||||
|
||||
<refsect1> |
||||
<title>Options</title> |
||||
|
||||
<para> |
||||
<variablelist> |
||||
<varlistentry> |
||||
<term><option>-i</option></term> |
||||
<term><option>--indivudual</option></term> |
||||
<listitem> |
||||
<para> |
||||
By default, <literal>pg_walsummary</literal> prints one line of output |
||||
for each range of one or more consecutive modified blocks. This can |
||||
make the output a lot briefer, since a relation where all blocks from |
||||
0 through 999 were modified will produce only one line of output rather |
||||
than 1000 separate lines. This option requests a separate line of |
||||
output for every modified block. |
||||
</para> |
||||
</listitem> |
||||
</varlistentry> |
||||
|
||||
<varlistentry> |
||||
<term><option>-q</option></term> |
||||
<term><option>--quiet</option></term> |
||||
<listitem> |
||||
<para> |
||||
Do not print any output, except for errors. This can be useful |
||||
when you want to know whether a WAL summary file can be successfully |
||||
parsed but don't care about the contents. |
||||
</para> |
||||
</listitem> |
||||
</varlistentry> |
||||
|
||||
<varlistentry> |
||||
<term><option>-?</option></term> |
||||
<term><option>--help</option></term> |
||||
<listitem> |
||||
<para> |
||||
Shows help about <application>pg_walsummary</application> command line |
||||
arguments, and exits. |
||||
</para> |
||||
</listitem> |
||||
</varlistentry> |
||||
|
||||
</variablelist> |
||||
</para> |
||||
|
||||
</refsect1> |
||||
|
||||
<refsect1> |
||||
<title>Environment</title> |
||||
|
||||
<para> |
||||
The environment variable <envar>PG_COLOR</envar> specifies whether to use |
||||
color in diagnostic messages. Possible values are |
||||
<literal>always</literal>, <literal>auto</literal> and |
||||
<literal>never</literal>. |
||||
</para> |
||||
</refsect1> |
||||
|
||||
<refsect1> |
||||
<title>See Also</title> |
||||
|
||||
<simplelist type="inline"> |
||||
<member><xref linkend="app-pgbasebackup"/></member> |
||||
<member><xref linkend="app-pgcombinebackup"/></member> |
||||
</simplelist> |
||||
</refsect1> |
||||
|
||||
</refentry> |
||||
@ -0,0 +1 @@ |
||||
pg_walsummary |
||||
@ -0,0 +1,48 @@ |
||||
#-------------------------------------------------------------------------
|
||||
#
|
||||
# Makefile for src/bin/pg_walsummary
|
||||
#
|
||||
# Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
|
||||
# Portions Copyright (c) 1994, Regents of the University of California
|
||||
#
|
||||
# src/bin/pg_walsummary/Makefile
|
||||
#
|
||||
#-------------------------------------------------------------------------
|
||||
|
||||
PGFILEDESC = "pg_walsummary - print contents of WAL summary files"
|
||||
PGAPPICON=win32
|
||||
|
||||
subdir = src/bin/pg_walsummary
|
||||
top_builddir = ../../..
|
||||
include $(top_builddir)/src/Makefile.global |
||||
|
||||
override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS) |
||||
LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils
|
||||
|
||||
OBJS = \
|
||||
$(WIN32RES) \
|
||||
pg_walsummary.o
|
||||
|
||||
all: pg_walsummary |
||||
|
||||
pg_walsummary: $(OBJS) | submake-libpgport submake-libpgfeutils |
||||
$(CC) $(CFLAGS) $^ $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
|
||||
|
||||
|
||||
install: all installdirs |
||||
$(INSTALL_PROGRAM) pg_walsummary$(X) '$(DESTDIR)$(bindir)/pg_walsummary$(X)'
|
||||
|
||||
installdirs: |
||||
$(MKDIR_P) '$(DESTDIR)$(bindir)'
|
||||
|
||||
uninstall: |
||||
rm -f '$(DESTDIR)$(bindir)/pg_walsummary$(X)'
|
||||
|
||||
clean distclean maintainer-clean: |
||||
rm -f pg_walsummary$(X) $(OBJS)
|
||||
|
||||
check: |
||||
$(prove_check)
|
||||
|
||||
installcheck: |
||||
$(prove_installcheck)
|
||||
@ -0,0 +1,30 @@ |
||||
# Copyright (c) 2022-2023, PostgreSQL Global Development Group |
||||
|
||||
pg_walsummary_sources = files( |
||||
'pg_walsummary.c', |
||||
) |
||||
|
||||
if host_system == 'windows' |
||||
pg_walsummary_sources += rc_bin_gen.process(win32ver_rc, extra_args: [ |
||||
'--NAME', 'pg_walsummary', |
||||
'--FILEDESC', 'pg_walsummary - print contents of WAL summary files',]) |
||||
endif |
||||
|
||||
pg_walsummary = executable('pg_walsummary', |
||||
pg_walsummary_sources, |
||||
dependencies: [frontend_code], |
||||
kwargs: default_bin_args, |
||||
) |
||||
bin_targets += pg_walsummary |
||||
|
||||
tests += { |
||||
'name': 'pg_walsummary', |
||||
'sd': meson.current_source_dir(), |
||||
'bd': meson.current_build_dir(), |
||||
'tap': { |
||||
'tests': [ |
||||
't/001_basic.pl', |
||||
't/002_blocks.pl', |
||||
], |
||||
} |
||||
} |
||||
@ -0,0 +1,6 @@ |
||||
# src/bin/pg_combinebackup/nls.mk
|
||||
CATALOG_NAME = pg_walsummary
|
||||
GETTEXT_FILES = $(FRONTEND_COMMON_GETTEXT_FILES) \
|
||||
pg_walsummary.c
|
||||
GETTEXT_TRIGGERS = $(FRONTEND_COMMON_GETTEXT_TRIGGERS)
|
||||
GETTEXT_FLAGS = $(FRONTEND_COMMON_GETTEXT_FLAGS)
|
||||
@ -0,0 +1,280 @@ |
||||
/*-------------------------------------------------------------------------
|
||||
* |
||||
* pg_walsummary.c |
||||
* Prints the contents of WAL summary files. |
||||
* |
||||
* Copyright (c) 2017-2023, PostgreSQL Global Development Group |
||||
* |
||||
* IDENTIFICATION |
||||
* src/bin/pg_walsummary/pg_walsummary.c |
||||
* |
||||
*------------------------------------------------------------------------- |
||||
*/ |
||||
#include "postgres_fe.h" |
||||
|
||||
#include <fcntl.h> |
||||
#include <limits.h> |
||||
|
||||
#include "common/blkreftable.h" |
||||
#include "common/logging.h" |
||||
#include "fe_utils/option_utils.h" |
||||
#include "lib/stringinfo.h" |
||||
#include "getopt_long.h" |
||||
|
||||
typedef struct ws_options |
||||
{ |
||||
bool individual; |
||||
bool quiet; |
||||
} ws_options; |
||||
|
||||
typedef struct ws_file_info |
||||
{ |
||||
int fd; |
||||
char *filename; |
||||
} ws_file_info; |
||||
|
||||
static BlockNumber *block_buffer = NULL; |
||||
static unsigned block_buffer_size = 512; /* Initial size. */ |
||||
|
||||
static void dump_one_relation(ws_options *opt, RelFileLocator *rlocator, |
||||
ForkNumber forknum, BlockNumber limit_block, |
||||
BlockRefTableReader *reader); |
||||
static void help(const char *progname); |
||||
static int compare_block_numbers(const void *a, const void *b); |
||||
static int walsummary_read_callback(void *callback_arg, void *data, |
||||
int length); |
||||
static void walsummary_error_callback(void *callback_arg, char *fmt,...) pg_attribute_printf(2, 3); |
||||
|
||||
/*
|
||||
* Main program. |
||||
*/ |
||||
int |
||||
main(int argc, char *argv[]) |
||||
{ |
||||
static struct option long_options[] = { |
||||
{"individual", no_argument, NULL, 'i'}, |
||||
{"quiet", no_argument, NULL, 'q'}, |
||||
{NULL, 0, NULL, 0} |
||||
}; |
||||
|
||||
const char *progname; |
||||
int optindex; |
||||
int c; |
||||
ws_options opt; |
||||
|
||||
memset(&opt, 0, sizeof(ws_options)); |
||||
|
||||
pg_logging_init(argv[0]); |
||||
progname = get_progname(argv[0]); |
||||
handle_help_version_opts(argc, argv, progname, help); |
||||
|
||||
/* process command-line options */ |
||||
while ((c = getopt_long(argc, argv, "f:iqw:", |
||||
long_options, &optindex)) != -1) |
||||
{ |
||||
switch (c) |
||||
{ |
||||
case 'i': |
||||
opt.individual = true; |
||||
break; |
||||
case 'q': |
||||
opt.quiet = true; |
||||
break; |
||||
default: |
||||
/* getopt_long already emitted a complaint */ |
||||
pg_log_error_hint("Try \"%s --help\" for more information.", progname); |
||||
exit(1); |
||||
} |
||||
} |
||||
|
||||
if (optind >= argc) |
||||
{ |
||||
pg_log_error("%s: no input files specified", progname); |
||||
pg_log_error_hint("Try \"%s --help\" for more information.", progname); |
||||
exit(1); |
||||
} |
||||
|
||||
while (optind < argc) |
||||
{ |
||||
ws_file_info ws; |
||||
BlockRefTableReader *reader; |
||||
RelFileLocator rlocator; |
||||
ForkNumber forknum; |
||||
BlockNumber limit_block; |
||||
|
||||
ws.filename = argv[optind++]; |
||||
if ((ws.fd = open(ws.filename, O_RDONLY | PG_BINARY, 0)) < 0) |
||||
pg_fatal("could not open file \"%s\": %m", ws.filename); |
||||
|
||||
reader = CreateBlockRefTableReader(walsummary_read_callback, &ws, |
||||
ws.filename, |
||||
walsummary_error_callback, NULL); |
||||
while (BlockRefTableReaderNextRelation(reader, &rlocator, &forknum, |
||||
&limit_block)) |
||||
dump_one_relation(&opt, &rlocator, forknum, limit_block, reader); |
||||
|
||||
DestroyBlockRefTableReader(reader); |
||||
close(ws.fd); |
||||
} |
||||
|
||||
exit(0); |
||||
} |
||||
|
||||
/*
|
||||
* Dump details for one relation. |
||||
*/ |
||||
static void |
||||
dump_one_relation(ws_options *opt, RelFileLocator *rlocator, |
||||
ForkNumber forknum, BlockNumber limit_block, |
||||
BlockRefTableReader *reader) |
||||
{ |
||||
unsigned i = 0; |
||||
unsigned nblocks; |
||||
BlockNumber startblock = InvalidBlockNumber; |
||||
BlockNumber endblock = InvalidBlockNumber; |
||||
|
||||
/* Dump limit block, if any. */ |
||||
if (limit_block != InvalidBlockNumber) |
||||
printf("TS %u, DB %u, REL %u, FORK %s: limit %u\n", |
||||
rlocator->spcOid, rlocator->dbOid, rlocator->relNumber, |
||||
forkNames[forknum], limit_block); |
||||
|
||||
/* If we haven't allocated a block buffer yet, do that now. */ |
||||
if (block_buffer == NULL) |
||||
block_buffer = palloc_array(BlockNumber, block_buffer_size); |
||||
|
||||
/* Try to fill the block buffer. */ |
||||
nblocks = BlockRefTableReaderGetBlocks(reader, |
||||
block_buffer, |
||||
block_buffer_size); |
||||
|
||||
/* If we filled the block buffer completely, we must enlarge it. */ |
||||
while (nblocks >= block_buffer_size) |
||||
{ |
||||
unsigned new_size; |
||||
|
||||
/* Double the size, being careful about overflow. */ |
||||
new_size = block_buffer_size * 2; |
||||
if (new_size < block_buffer_size) |
||||
new_size = PG_UINT32_MAX; |
||||
block_buffer = repalloc_array(block_buffer, BlockNumber, new_size); |
||||
|
||||
/* Try to fill the newly-allocated space. */ |
||||
nblocks += |
||||
BlockRefTableReaderGetBlocks(reader, |
||||
block_buffer + block_buffer_size, |
||||
new_size - block_buffer_size); |
||||
|
||||
/* Save the new size for later calls. */ |
||||
block_buffer_size = new_size; |
||||
} |
||||
|
||||
/* If we don't need to produce any output, skip the rest of this. */ |
||||
if (opt->quiet) |
||||
return; |
||||
|
||||
/*
|
||||
* Sort the returned block numbers. If the block reference table was using |
||||
* the bitmap representation for a given chunk, the block numbers in that |
||||
* chunk will already be sorted, but when the array-of-offsets |
||||
* representation is used, we can receive block numbers here out of order. |
||||
*/ |
||||
qsort(block_buffer, nblocks, sizeof(BlockNumber), compare_block_numbers); |
||||
|
||||
/* Dump block references. */ |
||||
while (i < nblocks) |
||||
{ |
||||
/*
|
||||
* Find the next range of blocks to print, but if --individual was |
||||
* specified, then consider each block a separate range. |
||||
*/ |
||||
startblock = endblock = block_buffer[i++]; |
||||
if (!opt->individual) |
||||
{ |
||||
while (i < nblocks && block_buffer[i] == endblock + 1) |
||||
{ |
||||
endblock++; |
||||
i++; |
||||
} |
||||
} |
||||
|
||||
/* Format this range of block numbers as a string. */ |
||||
if (startblock == endblock) |
||||
printf("TS %u, DB %u, REL %u, FORK %s: block %u\n", |
||||
rlocator->spcOid, rlocator->dbOid, rlocator->relNumber, |
||||
forkNames[forknum], startblock); |
||||
else |
||||
printf("TS %u, DB %u, REL %u, FORK %s: blocks %u..%u\n", |
||||
rlocator->spcOid, rlocator->dbOid, rlocator->relNumber, |
||||
forkNames[forknum], startblock, endblock); |
||||
} |
||||
} |
||||
|
||||
/*
|
||||
* Quicksort comparator for block numbers. |
||||
*/ |
||||
static int |
||||
compare_block_numbers(const void *a, const void *b) |
||||
{ |
||||
BlockNumber aa = *(BlockNumber *) a; |
||||
BlockNumber bb = *(BlockNumber *) b; |
||||
|
||||
if (aa > bb) |
||||
return 1; |
||||
else if (aa == bb) |
||||
return 0; |
||||
else |
||||
return -1; |
||||
} |
||||
|
||||
/*
|
||||
* Error callback. |
||||
*/ |
||||
void |
||||
walsummary_error_callback(void *callback_arg, char *fmt,...) |
||||
{ |
||||
va_list ap; |
||||
|
||||
va_start(ap, fmt); |
||||
pg_log_generic_v(PG_LOG_ERROR, PG_LOG_PRIMARY, fmt, ap); |
||||
va_end(ap); |
||||
|
||||
exit(1); |
||||
} |
||||
|
||||
/*
|
||||
* Read callback. |
||||
*/ |
||||
int |
||||
walsummary_read_callback(void *callback_arg, void *data, int length) |
||||
{ |
||||
ws_file_info *ws = callback_arg; |
||||
int rc; |
||||
|
||||
if ((rc = read(ws->fd, data, length)) < 0) |
||||
pg_fatal("could not read file \"%s\": %m", ws->filename); |
||||
|
||||
return rc; |
||||
} |
||||
|
||||
/*
|
||||
* help |
||||
* |
||||
* Prints help page for the program |
||||
* |
||||
* progname: the name of the executed program, such as "pg_walsummary" |
||||
*/ |
||||
static void |
||||
help(const char *progname) |
||||
{ |
||||
printf(_("%s prints the contents of a WAL summary file.\n\n"), progname); |
||||
printf(_("Usage:\n")); |
||||
printf(_(" %s [OPTION]... FILE...\n"), progname); |
||||
printf(_("\nOptions:\n")); |
||||
printf(_(" -i, --individual list block numbers individually, not as ranges\n")); |
||||
printf(_(" -q, --quiet don't print anything, just parse the files\n")); |
||||
printf(_(" -?, --help show this help, then exit\n")); |
||||
|
||||
printf(_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT); |
||||
printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL); |
||||
} |
||||
@ -0,0 +1,19 @@ |
||||
# Copyright (c) 2021-2023, PostgreSQL Global Development Group |
||||
|
||||
use strict; |
||||
use warnings; |
||||
use PostgreSQL::Test::Utils; |
||||
use Test::More; |
||||
|
||||
my $tempdir = PostgreSQL::Test::Utils::tempdir; |
||||
|
||||
program_help_ok('pg_walsummary'); |
||||
program_version_ok('pg_walsummary'); |
||||
program_options_handling_ok('pg_walsummary'); |
||||
|
||||
command_fails_like( |
||||
['pg_walsummary'], |
||||
qr/no input files specified/, |
||||
'input files must be specified'); |
||||
|
||||
done_testing(); |
||||
@ -0,0 +1,88 @@ |
||||
# Copyright (c) 2021-2023, PostgreSQL Global Development Group |
||||
|
||||
use strict; |
||||
use warnings; |
||||
use File::Compare; |
||||
use PostgreSQL::Test::Cluster; |
||||
use PostgreSQL::Test::Utils; |
||||
use Test::More; |
||||
|
||||
# Set up a new database instance. |
||||
my $node1 = PostgreSQL::Test::Cluster->new('node1'); |
||||
$node1->init(has_archiving => 1, allows_streaming => 1); |
||||
$node1->append_conf('postgresql.conf', 'summarize_wal = on'); |
||||
$node1->start; |
||||
|
||||
# See what's been summarized up until now. |
||||
my $progress = $node1->safe_psql('postgres', <<EOM); |
||||
SELECT summarized_tli, summarized_lsn FROM pg_get_wal_summarizer_state() |
||||
EOM |
||||
my ($summarized_tli, $summarized_lsn) = split(/\|/, $progress); |
||||
note("before insert, summarized TLI $summarized_tli through $summarized_lsn"); |
||||
|
||||
# Create a table and insert a few test rows into it. VACUUM FREEZE it so that |
||||
# autovacuum doesn't induce any future modifications unexpectedly. Then |
||||
# trigger a checkpoint. |
||||
$node1->safe_psql('postgres', <<EOM); |
||||
CREATE TABLE mytable (a int, b text); |
||||
INSERT INTO mytable |
||||
SELECT |
||||
g, random()::text||random()::text||random()::text||random()::text |
||||
FROM |
||||
generate_series(1, 400) g; |
||||
VACUUM FREEZE; |
||||
CHECKPOINT; |
||||
EOM |
||||
|
||||
# Wait for a new summary to show up. |
||||
$node1->poll_query_until('postgres', <<EOM); |
||||
SELECT EXISTS ( |
||||
SELECT * from pg_available_wal_summaries() |
||||
WHERE tli = $summarized_tli AND end_lsn > '$summarized_lsn' |
||||
) |
||||
EOM |
||||
|
||||
# Again check the progress of WAL summarization. |
||||
$progress = $node1->safe_psql('postgres', <<EOM); |
||||
SELECT summarized_tli, summarized_lsn FROM pg_get_wal_summarizer_state() |
||||
EOM |
||||
($summarized_tli, $summarized_lsn) = split(/\|/, $progress); |
||||
note("after insert, summarized TLI $summarized_tli through $summarized_lsn"); |
||||
|
||||
# Update a row in the first block of the table and trigger a checkpoint. |
||||
$node1->safe_psql('postgres', <<EOM); |
||||
UPDATE mytable SET b = 'abcdefghijklmnopqrstuvwxyz' WHERE a = 2; |
||||
CHECKPOINT; |
||||
EOM |
||||
|
||||
# Again wait for a new summary to show up. |
||||
$node1->poll_query_until('postgres', <<EOM); |
||||
SELECT EXISTS ( |
||||
SELECT * from pg_available_wal_summaries() |
||||
WHERE tli = $summarized_tli AND end_lsn > '$summarized_lsn' |
||||
) |
||||
EOM |
||||
|
||||
# Figure out the exact details for the new sumamry file. |
||||
my $details = $node1->safe_psql('postgres', <<EOM); |
||||
SELECT tli, start_lsn, end_lsn from pg_available_wal_summaries() |
||||
WHERE tli = $summarized_tli AND end_lsn > '$summarized_lsn' |
||||
EOM |
||||
my ($tli, $start_lsn, $end_lsn) = split(/\|/, $details); |
||||
note("examining summary for TLI $tli from $start_lsn to $end_lsn"); |
||||
|
||||
# Reconstruct the full pathname for the WAL summary file. |
||||
my $filename = sprintf "%s/pg_wal/summaries/%08s%08s%08s%08s%08s.summary", |
||||
$node1->data_dir, $tli, |
||||
split(m@/@, $start_lsn), |
||||
split(m@/@, $end_lsn); |
||||
ok(-f $filename, "WAL summary file exists"); |
||||
|
||||
# Run pg_walsummary on it. We expect block 0 to be modified, but block 1 |
||||
# to be unmodified, so the output should say block 0, not block 0..1 or |
||||
# similar. |
||||
my ($stdout, $stderr) = run_command([ 'pg_walsummary', $filename ]); |
||||
like($stdout, qr/FORK main: block 0$/m, "stdout shows block 0 modified"); |
||||
is($stderr, '', 'stderr is empty'); |
||||
|
||||
done_testing(); |
||||
Loading…
Reference in new issue