‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Saturday, September 18th, 2021 at 8:18 AM, Michael Paquier
<mich...@paquier.xyz> wrote:
> On Fri, Sep 17, 2021 at 08:12:42AM +0000, gkokola...@pm.me wrote:
>
> I have been digging into the issue I saw in the TAP tests when closing
> a segment, and found the problem. The way you manipulate
> frameInfo.contentSize by just setting it to WalSegSz when *opening*
> a segment causes problems on LZ4F_compressEnd(), making the code
> throw a ERROR_frameSize_wrong. In lz4frame.c, the end of
> LZ4F_compressEnd() triggers this check and the error:
> if (cctxPtr->prefs.frameInfo.contentSize) {
> if (cctxPtr->prefs.frameInfo.contentSize != cctxPtr->totalInSize)
> return err0r(LZ4F_ERROR_frameSize_wrong);
> }
>
> We don't really care about contentSize as long as a segment is not
> completed. Rather than filling contentSize all the time we write
> something, we'd better update frameInfo once the segment is
> completed and closed. That would also take take of the error as this
> is not checked if contentSize is 0. It seems to me that we should
> fill in the information when doing a CLOSE_NORMAL.
Thank you for the comment. I think that the opposite should be done. At the time
that the file is closed, the header is already written to disk. We have no way
to know that is not. If we need to go back to refill the information, we will
have to ask for the API to produce a new header. There is little guarantee that
the header size will be the same and as a consequence we will have to shift
the actual data around.
In the attached, the header is rewritten only when closing an incomplete
segment. For all intents and purposes that segment is not usable. However there
might be custom scripts that might want to attempt to parse even an otherwise
unusable file.
A different and easier approach would be to simply prepare the LZ4 context for
future actions and simply ignore the file.
>
> - if (stream->walmethod->compression() == 0 &&
> + if (stream->walmethod->compression() == COMPRESSION_NONE &&
> stream->walmethod->existsfile(fn))
> This one was a more serious issue, as the compression() callback would
> return an integer for the compression level but v5 compared it to a
> WalCompressionMethod. In order to take care of this issue, mainly for
> pg_basebackup, I think that we have to update the compression()
> callback to compression_method(), and it is cleaner to save the
> compression method as well as the compression level for the tar data.
>
Agreed.
> I am attaching a new patch, on which I have done many tweaks and
> adjustments while reviewing it. The attached patch fixes the second
> issue, and I have done nothing about the first issue yet, but that
> should be simple enough to address as this needs an update of the
> frame info when closing a completed segment. Could you look at it?
>
Thank you. Find v7 attached, rebased to the current head.
Cheers,
//Georgios
> Thanks,
> --
> MichaeFrom c3c2eca22102cd0186eb1975339248a200e1ceb9 Mon Sep 17 00:00:00 2001
From: Georgios Kokolatos <gkokola...@pm.me>
Date: Fri, 22 Oct 2021 13:14:15 +0000
Subject: [PATCH v7] Teach pg_receivewal to use LZ4 compression
The program pg_receivewal can use gzip compression to store the received WAL.
This commit teaches it to also be able to use LZ4 compression. It is required
that the binary is build using the -llz4 flag. It is enabled via the --with-lz4
flag on configuration time.
Previously, the user had to use the option --compress with a value between [0-9]
to denote that gzip compression was required. This specific behaviour has not
maintained. A newly introduced option --compression-method=[LZ4|gzip] can be
used to ask for the logs to be compressed. Compression values can be selected
only when the compression method is gzip. A compression value of 0 now returns
an error.
Under the hood there is nothing exceptional to be noted. Tar based archives have
not yet been taught to use LZ4 compression. If that is felt useful, then it is
easy to be added in the future.
Tests have been added to verify the creation and correctness of the generated
LZ4 files. The later is achieved by the use of LZ4 program, if present in the
installation.
---
doc/src/sgml/ref/pg_receivewal.sgml | 28 +-
src/Makefile.global.in | 1 +
src/bin/pg_basebackup/Makefile | 1 +
src/bin/pg_basebackup/pg_basebackup.c | 7 +-
src/bin/pg_basebackup/pg_receivewal.c | 274 +++++++++++++++----
src/bin/pg_basebackup/receivelog.c | 2 +-
src/bin/pg_basebackup/t/020_pg_receivewal.pl | 79 +++++-
src/bin/pg_basebackup/walmethods.c | 263 ++++++++++++++++--
src/bin/pg_basebackup/walmethods.h | 16 +-
src/tools/pgindent/typedefs.list | 1 +
10 files changed, 589 insertions(+), 83 deletions(-)
diff --git a/doc/src/sgml/ref/pg_receivewal.sgml b/doc/src/sgml/ref/pg_receivewal.sgml
index 9fde2fd2ef..bc2710131a 100644
--- a/doc/src/sgml/ref/pg_receivewal.sgml
+++ b/doc/src/sgml/ref/pg_receivewal.sgml
@@ -263,15 +263,35 @@ PostgreSQL documentation
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--compression-method=<replaceable class="parameter">level</replaceable></option></term>
+ <listitem>
+ <para>
+ Enables compression of write-ahead logs using the specified method.
+ Supported values are <literal>lz4</literal>, <literal>gzip</literal>
+ and <literal>none</literal>.
+ For the <productname>LZ4</productname> method to be available,
+ <productname>PostgreSQL</productname> must have been have been compiled
+ with <option>--with-lz4</option>.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>-Z <replaceable class="parameter">level</replaceable></option></term>
<term><option>--compress=<replaceable class="parameter">level</replaceable></option></term>
<listitem>
<para>
- Enables gzip compression of write-ahead logs, and specifies the
- compression level (0 through 9, 0 being no compression and 9 being best
- compression). The suffix <filename>.gz</filename> will
- automatically be added to all filenames.
+ Specifies the compression level (<literal>1</literal> through
+ <literal>9</literal>, <literal>1</literal> being worst compression
+ and <literal>9</literal> being best compression) for
+ <application>gzip</application> compressed WAL segments. The
+ default value is <literal>5</literal>.
+ </para>
+
+ <para>
+ This option requires <option>--compression-method</option> to be
+ specified with <literal>gzip</literal>.
</para>
</listitem>
</varlistentry>
diff --git a/src/Makefile.global.in b/src/Makefile.global.in
index 533c12fef9..05c54b27de 100644
--- a/src/Makefile.global.in
+++ b/src/Makefile.global.in
@@ -350,6 +350,7 @@ XGETTEXT = @XGETTEXT@
GZIP = gzip
BZIP2 = bzip2
+LZ4 = lz4
DOWNLOAD = wget -O $@ --no-use-server-timestamps
#DOWNLOAD = curl -o $@
diff --git a/src/bin/pg_basebackup/Makefile b/src/bin/pg_basebackup/Makefile
index 459d514183..387d728345 100644
--- a/src/bin/pg_basebackup/Makefile
+++ b/src/bin/pg_basebackup/Makefile
@@ -24,6 +24,7 @@ export TAR
# used by the command "gzip" to pass down options, so stick with a different
# name.
export GZIP_PROGRAM=$(GZIP)
+export LZ4
override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
LDFLAGS_INTERNAL += -L$(top_builddir)/src/fe_utils -lpgfeutils $(libpq_pgport)
diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index 27ee6394cf..cdea3711b7 100644
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -555,10 +555,13 @@ LogStreamerMain(logstreamer_param *param)
stream.replication_slot = replication_slot;
if (format == 'p')
- stream.walmethod = CreateWalDirectoryMethod(param->xlog, 0,
+ stream.walmethod = CreateWalDirectoryMethod(param->xlog,
+ COMPRESSION_NONE, 0,
stream.do_sync);
else
- stream.walmethod = CreateWalTarMethod(param->xlog, compresslevel,
+ stream.walmethod = CreateWalTarMethod(param->xlog,
+ COMPRESSION_NONE, /* ignored */
+ compresslevel,
stream.do_sync);
if (!ReceiveXlogStream(param->bgconn, &stream))
diff --git a/src/bin/pg_basebackup/pg_receivewal.c b/src/bin/pg_basebackup/pg_receivewal.c
index 04ba20b197..d22fd63770 100644
--- a/src/bin/pg_basebackup/pg_receivewal.c
+++ b/src/bin/pg_basebackup/pg_receivewal.c
@@ -29,9 +29,16 @@
#include "receivelog.h"
#include "streamutil.h"
+#ifdef HAVE_LIBLZ4
+#include "lz4frame.h"
+#endif
+
/* Time to sleep between reconnection attempts */
#define RECONNECT_SLEEP_TIME 5
+/* this is just the redefinition of a libz constant */
+#define Z_DEFAULT_COMPRESSION (-1)
+
/* Global options */
static char *basedir = NULL;
static int verbose = 0;
@@ -45,6 +52,7 @@ static bool do_drop_slot = false;
static bool do_sync = true;
static bool synchronous = false;
static char *replication_slot = NULL;
+static WalCompressionMethod compression_method = COMPRESSION_NONE;
static XLogRecPtr endpos = InvalidXLogRecPtr;
@@ -63,16 +71,6 @@ disconnect_atexit(void)
PQfinish(conn);
}
-/* Routines to evaluate segment file format */
-#define IsCompressXLogFileName(fname) \
- (strlen(fname) == XLOG_FNAME_LEN + strlen(".gz") && \
- strspn(fname, "0123456789ABCDEF") == XLOG_FNAME_LEN && \
- strcmp((fname) + XLOG_FNAME_LEN, ".gz") == 0)
-#define IsPartialCompressXLogFileName(fname) \
- (strlen(fname) == XLOG_FNAME_LEN + strlen(".gz.partial") && \
- strspn(fname, "0123456789ABCDEF") == XLOG_FNAME_LEN && \
- strcmp((fname) + XLOG_FNAME_LEN, ".gz.partial") == 0)
-
static void
usage(void)
{
@@ -92,7 +90,9 @@ usage(void)
printf(_(" --synchronous flush write-ahead log immediately after writing\n"));
printf(_(" -v, --verbose output verbose messages\n"));
printf(_(" -V, --version output version information, then exit\n"));
- printf(_(" -Z, --compress=0-9 compress logs with given compression level\n"));
+ printf(_(" --compression-method=METHOD\n"
+ " method to compress logs\n"));
+ printf(_(" -Z, --compress=1-9 compress logs with given compression level\n"));
printf(_(" -?, --help show this help, then exit\n"));
printf(_("\nConnection options:\n"));
printf(_(" -d, --dbname=CONNSTR connection string\n"));
@@ -108,6 +108,79 @@ usage(void)
printf(_("%s home page: <%s>\n"), PACKAGE_NAME, PACKAGE_URL);
}
+
+/*
+ * Check if the filename looks like an xlog file. Also note if it is partial
+ * and/or compressed file.
+ */
+static bool
+is_xlogfilename(const char *filename, bool *ispartial,
+ WalCompressionMethod *wal_compression_method)
+{
+ size_t fname_len = strlen(filename);
+ size_t xlog_pattern_len = strspn(filename, "0123456789ABCDEF");
+
+ /* File does not look like a XLOG file */
+ if (xlog_pattern_len != XLOG_FNAME_LEN)
+ return false;
+
+ /* File looks like a complete uncompressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN)
+ {
+ *ispartial = false;
+ *wal_compression_method = COMPRESSION_NONE;
+ return true;
+ }
+
+ /* File looks like a complete zlib compressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN + strlen(".gz") &&
+ strcmp(filename + XLOG_FNAME_LEN, ".gz") == 0)
+ {
+ *ispartial = false;
+ *wal_compression_method = COMPRESSION_ZLIB;
+ return true;
+ }
+
+ /* File looks like a complete LZ4 compressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN + strlen(".lz4") &&
+ strcmp(filename + XLOG_FNAME_LEN, ".lz4") == 0)
+ {
+ *ispartial = false;
+ *wal_compression_method = COMPRESSION_LZ4;
+ return true;
+ }
+
+ /* File looks like a partial uncompressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN + strlen(".partial") &&
+ strcmp(filename + XLOG_FNAME_LEN, ".partial") == 0)
+ {
+ *ispartial = true;
+ *wal_compression_method = COMPRESSION_NONE;
+ return true;
+ }
+
+ /* File looks like a partial zlib compressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN + strlen(".gz.partial") &&
+ strcmp(filename + XLOG_FNAME_LEN, ".gz.partial") == 0)
+ {
+ *ispartial = true;
+ *wal_compression_method = COMPRESSION_ZLIB;
+ return true;
+ }
+
+ /* File looks like a partial LZ4 compressed XLOG file */
+ if (fname_len == XLOG_FNAME_LEN + strlen(".lz4.partial") &&
+ strcmp(filename + XLOG_FNAME_LEN, ".lz4.partial") == 0)
+ {
+ *ispartial = true;
+ *wal_compression_method = COMPRESSION_LZ4;
+ return true;
+ }
+
+ /* File does not look like something we recognise */
+ return false;
+}
+
static bool
stop_streaming(XLogRecPtr xlogpos, uint32 timeline, bool segment_finished)
{
@@ -213,33 +286,11 @@ FindStreamingStart(uint32 *tli)
{
uint32 tli;
XLogSegNo segno;
+ WalCompressionMethod wal_compression_method;
bool ispartial;
- bool iscompress;
- /*
- * Check if the filename looks like an xlog file, or a .partial file.
- */
- if (IsXLogFileName(dirent->d_name))
- {
- ispartial = false;
- iscompress = false;
- }
- else if (IsPartialXLogFileName(dirent->d_name))
- {
- ispartial = true;
- iscompress = false;
- }
- else if (IsCompressXLogFileName(dirent->d_name))
- {
- ispartial = false;
- iscompress = true;
- }
- else if (IsPartialCompressXLogFileName(dirent->d_name))
- {
- ispartial = true;
- iscompress = true;
- }
- else
+ if (!is_xlogfilename(dirent->d_name,
+ &ispartial, &wal_compression_method))
continue;
/*
@@ -250,14 +301,18 @@ FindStreamingStart(uint32 *tli)
/*
* Check that the segment has the right size, if it's supposed to be
* completed. For non-compressed segments just check the on-disk size
- * and see if it matches a completed segment. For compressed segments,
- * look at the last 4 bytes of the compressed file, which is where the
- * uncompressed size is located for gz files with a size lower than
- * 4GB, and then compare it to the size of a completed segment. The 4
- * last bytes correspond to the ISIZE member according to
- * http://www.zlib.org/rfc-gzip.html.
+ * and see if it matches a completed segment. For zlib compressed
+ * segments, look at the last 4 bytes of the compressed file, which is
+ * where the uncompressed size is located for gz files with a size
+ * lower than 4GB, and then compare it to the size of a completed
+ * segment. The 4 last bytes correspond to the ISIZE member according
+ * to http://www.zlib.org/rfc-gzip.html.
+ *
+ * For LZ4 compressed segments read the header using the exposed API
+ * and compare the uncompressed file size, stored in
+ * LZ4F_frameInfo_t{.contentSize}, to that of a completed segment.
*/
- if (!ispartial && !iscompress)
+ if (!ispartial && wal_compression_method == COMPRESSION_NONE)
{
struct stat statbuf;
char fullpath[MAXPGPATH * 2];
@@ -276,7 +331,7 @@ FindStreamingStart(uint32 *tli)
continue;
}
}
- else if (!ispartial && iscompress)
+ else if (!ispartial && wal_compression_method == COMPRESSION_ZLIB)
{
int fd;
char buf[4];
@@ -322,6 +377,80 @@ FindStreamingStart(uint32 *tli)
continue;
}
}
+ else if (!ispartial && compression_method == COMPRESSION_LZ4)
+ {
+#ifdef HAVE_LIBLZ4
+ int fd;
+ int r;
+ size_t consumed_len = LZ4F_HEADER_SIZE_MAX;
+ char buf[LZ4F_HEADER_SIZE_MAX];
+ char fullpath[MAXPGPATH * 2];
+ LZ4F_frameInfo_t frame_info = {0};
+ LZ4F_decompressionContext_t ctx = NULL;
+ LZ4F_errorCode_t status;
+
+ snprintf(fullpath, sizeof(fullpath), "%s/%s", basedir, dirent->d_name);
+
+ fd = open(fullpath, O_RDONLY | PG_BINARY, 0);
+ if (fd < 0)
+ {
+ pg_log_error("could not open file \"%s\": %m", fullpath);
+ exit(1);
+ }
+
+ r = read(fd, buf, sizeof(buf));
+ if (r != sizeof(buf))
+ {
+ if (r < 0)
+ pg_log_error("could not read file \"%s\": %m", fullpath);
+ else
+ pg_log_error("could not read file \"%s\": read %d of %zu",
+ fullpath, r, sizeof(buf));
+ exit(1);
+ }
+ close(fd);
+
+ status = LZ4F_createDecompressionContext(&ctx, LZ4F_VERSION);
+ if (LZ4F_isError(status))
+ {
+ pg_log_error("could not create LZ4 decompression context: %s",
+ LZ4F_getErrorName(status));
+ exit(1);
+ }
+
+ LZ4F_getFrameInfo(ctx, &frame_info, (void *) buf, &consumed_len);
+ if (consumed_len <= LZ4F_HEADER_SIZE_MIN ||
+ consumed_len >= LZ4F_HEADER_SIZE_MAX)
+ {
+ pg_log_warning("compressed segment file \"%s\" has incorrect header size %lu, skipping",
+ dirent->d_name, consumed_len);
+ (void) LZ4F_freeDecompressionContext(ctx);
+ continue;
+ }
+
+ if (frame_info.contentSize != WalSegSz)
+ {
+ pg_log_warning("compressed segment file \"%s\" has incorrect uncompressed size %lld, skipping",
+ dirent->d_name, frame_info.contentSize);
+ (void) LZ4F_freeDecompressionContext(ctx);
+ continue;
+ }
+
+ status = LZ4F_freeDecompressionContext(ctx);
+ if (LZ4F_isError(status))
+ {
+ pg_log_error("could not free LZ4 decompression context: %s",
+ LZ4F_getErrorName(status));
+ exit(1);
+ }
+#else
+ pg_log_error("could not check segment file \"%s\" compressed with LZ4",
+ dirent->d_name);
+ pg_log_error("this build does not support compression with %s",
+ "LZ4");
+ exit(1);
+#endif
+ }
/* Looks like a valid segment. Remember that we saw it. */
if ((segno > high_segno) ||
@@ -457,7 +586,9 @@ StreamLog(void)
stream.synchronous = synchronous;
stream.do_sync = do_sync;
stream.mark_done = false;
- stream.walmethod = CreateWalDirectoryMethod(basedir, compresslevel,
+ stream.walmethod = CreateWalDirectoryMethod(basedir,
+ compression_method,
+ compresslevel,
stream.do_sync);
stream.partial_suffix = ".partial";
stream.replication_slot = replication_slot;
@@ -510,6 +641,7 @@ main(int argc, char **argv)
{"status-interval", required_argument, NULL, 's'},
{"slot", required_argument, NULL, 'S'},
{"verbose", no_argument, NULL, 'v'},
+ {"compression-method", required_argument, NULL, 'I'},
{"compress", required_argument, NULL, 'Z'},
/* action */
{"create-slot", no_argument, NULL, 1},
@@ -595,8 +727,22 @@ main(int argc, char **argv)
case 'v':
verbose++;
break;
+ case 'I':
+ if (pg_strcasecmp(optarg, "gzip") == 0)
+ compression_method = COMPRESSION_ZLIB;
+ else if (pg_strcasecmp(optarg, "lz4") == 0)
+ compression_method = COMPRESSION_LZ4;
+ else if (pg_strcasecmp(optarg, "none") == 0)
+ compression_method = COMPRESSION_NONE;
+ else
+ {
+ pg_log_error("invalid value \"%s\" for option %s",
+ optarg, "--compress-method");
+ exit(1);
+ }
+ break;
case 'Z':
- if (!option_parse_int(optarg, "-Z/--compress", 0, 9,
+ if (!option_parse_int(optarg, "-Z/--compress", 1, 9,
&compresslevel))
exit(1);
break;
@@ -676,13 +822,43 @@ main(int argc, char **argv)
exit(1);
}
+
+ /*
+ * Compression related arguments
+ */
+ if (compression_method != COMPRESSION_NONE)
+ {
#ifndef HAVE_LIBZ
- if (compresslevel != 0)
+ if (compression_method == COMPRESSION_ZLIB)
+ {
+ pg_log_error("this build does not support compression with %s",
+ "gzip");
+ exit(1);
+ }
+#endif
+#ifndef HAVE_LIBLZ4
+ if (compression_method == COMPRESSION_LZ4)
+ {
+ pg_log_error("this build does not support compression with %s",
+ "LZ4");
+ exit(1);
+ }
+#endif
+ }
+
+ if (compression_method != COMPRESSION_ZLIB && compresslevel != 0)
{
- pg_log_error("this build does not support compression");
+ pg_log_error("can only use --compress with --compression-method=gzip");
+ fprintf(stderr, _("Try \"%s --help\" for more information.\n"),
+ progname);
exit(1);
}
-#endif
+
+ if (compression_method == COMPRESSION_ZLIB && compresslevel == 0)
+ {
+ pg_log_info("no --compression specified, will be using the library default");
+ compresslevel = Z_DEFAULT_COMPRESSION;
+ }
/*
* Check existence of destination folder.
diff --git a/src/bin/pg_basebackup/receivelog.c b/src/bin/pg_basebackup/receivelog.c
index 72b8d9e315..2d4f660daa 100644
--- a/src/bin/pg_basebackup/receivelog.c
+++ b/src/bin/pg_basebackup/receivelog.c
@@ -109,7 +109,7 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
* When streaming to tar, no file with this name will exist before, so we
* never have to verify a size.
*/
- if (stream->walmethod->compression() == 0 &&
+ if (stream->walmethod->compression_method() == COMPRESSION_NONE &&
stream->walmethod->existsfile(fn))
{
size = stream->walmethod->get_file_size(fn);
diff --git a/src/bin/pg_basebackup/t/020_pg_receivewal.pl b/src/bin/pg_basebackup/t/020_pg_receivewal.pl
index 2da200396e..a37b92d6af 100644
--- a/src/bin/pg_basebackup/t/020_pg_receivewal.pl
+++ b/src/bin/pg_basebackup/t/020_pg_receivewal.pl
@@ -5,7 +5,7 @@ use strict;
use warnings;
use PostgreSQL::Test::Utils;
use PostgreSQL::Test::Cluster;
-use Test::More tests => 31;
+use Test::More tests => 38;
program_help_ok('pg_receivewal');
program_version_ok('pg_receivewal');
@@ -33,6 +33,13 @@ $primary->command_fails(
$primary->command_fails(
[ 'pg_receivewal', '-D', $stream_dir, '--synchronous', '--no-sync' ],
'failure if --synchronous specified with --no-sync');
+$primary->command_fails_like(
+ [
+ 'pg_receivewal', '-D', $stream_dir, '--compression-method', 'none',
+ '--compress', '1'
+ ],
+ qr/\Qpg_receivewal: error: can only use --compress with --compression-method=gzip/,
+ 'failure if --compression-method=none specified with --compress');
# Slot creation and drop
my $slot_name = 'test';
@@ -41,7 +48,7 @@ $primary->command_ok(
'creating a replication slot');
my $slot = $primary->slot($slot_name);
is($slot->{'slot_type'}, 'physical', 'physical replication slot was created');
-is($slot->{'restart_lsn'}, '', 'restart LSN of new slot is null');
+is($slot->{'restart_lsn'}, '', 'restart LSN of new slot is null');
$primary->command_ok([ 'pg_receivewal', '--slot', $slot_name, '--drop-slot' ],
'dropping a replication slot');
is($primary->slot($slot_name)->{'slot_type'},
@@ -90,8 +97,11 @@ SKIP:
# a valid value.
$primary->command_ok(
[
- 'pg_receivewal', '-D', $stream_dir, '--verbose',
- '--endpos', $nextlsn, '--compress', '1 ',
+ 'pg_receivewal', '-D',
+ $stream_dir, '--verbose',
+ '--endpos', $nextlsn,
+ '--compression-method', 'gzip',
+ '--compress', '1 ',
'--no-loop'
],
"streaming some WAL using ZLIB compression");
@@ -128,8 +138,65 @@ SKIP:
"gzip verified the integrity of compressed WAL segments");
}
+# Check LZ4 compression if available
+SKIP:
+{
+ skip "postgres was not built with LZ4 support", 5
+ if (!check_pg_config("#define HAVE_LIBLZ4 1"));
+
+ # Generate more WAL including one completed, compressed segment.
+ $primary->psql('postgres', 'SELECT pg_switch_wal();');
+ $nextlsn =
+ $primary->safe_psql('postgres', 'SELECT pg_current_wal_insert_lsn();');
+ chomp($nextlsn);
+ $primary->psql('postgres',
+ 'INSERT INTO test_table VALUES (generate_series(201,300));');
+
+ # Stream up to the given position
+ $primary->command_ok(
+ [
+ 'pg_receivewal', '-D',
+ $stream_dir, '--verbose',
+ '--endpos', $nextlsn,
+ '--no-loop', '--compression-method',
+ 'lz4'
+ ],
+ 'streaming some WAL using --compression-method=lz4');
+
+ # Verify that the stored files are generated with their expected
+ # names.
+ my @lz4_wals = glob "$stream_dir/*.lz4";
+ is(scalar(@lz4_wals), 1,
+ "one WAL segment compressed with LZ4 was created");
+ my @lz4_partial_wals = glob "$stream_dir/*.lz4.partial";
+ is(scalar(@lz4_partial_wals),
+ 1, "one partial WAL segment compressed with LZ4 was created");
+
+ # Verify that the start streaming position is computed correctly by
+ # comparing it with the partial file generated previously. The name
+ # of the previous partial, now-completed WAL segment is updated, keeping
+ # its base number.
+ $partial_wals[0] =~ s/(\.gz)?\.partial$/.lz4/;
+ is($lz4_wals[0] eq $partial_wals[0],
+ 1, "one partial WAL segment is now completed");
+ # Update the list of partial wals with the current one.
+ @partial_wals = @lz4_partial_wals;
+
+ # Check the integrity of the completed segment, if LZ4 is an available
+ # command.
+ my $lz4 = $ENV{LZ4};
+ skip "program lz4 is not found in your system", 1
+ if ( !defined $lz4
+ || $lz4 eq ''
+ || system_log($lz4, '--version') != 0);
+
+ my $lz4_is_valid = system_log($lz4, '-t', @lz4_wals);
+ is($lz4_is_valid, 0,
+ "lz4 verified the integrity of compressed WAL segments");
+}
+
# Verify that the start streaming position is computed and that the value is
-# correct regardless of whether ZLIB is available.
+# correct regardless of whether any compression is available.
$primary->psql('postgres', 'SELECT pg_switch_wal();');
$nextlsn =
$primary->safe_psql('postgres', 'SELECT pg_current_wal_insert_lsn();');
@@ -142,7 +209,7 @@ $primary->command_ok(
],
"streaming some WAL");
-$partial_wals[0] =~ s/(\.gz)?.partial//;
+$partial_wals[0] =~ s/(\.gz|\.lz4)?.partial//;
ok(-e $partial_wals[0], "check that previously partial WAL is now complete");
# Permissions on WAL files should be default
diff --git a/src/bin/pg_basebackup/walmethods.c b/src/bin/pg_basebackup/walmethods.c
index 8695647db4..bc26a71b75 100644
--- a/src/bin/pg_basebackup/walmethods.c
+++ b/src/bin/pg_basebackup/walmethods.c
@@ -17,6 +17,10 @@
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
+
+#ifdef HAVE_LIBLZ4
+#include <lz4frame.h>
+#endif
#ifdef HAVE_LIBZ
#include <zlib.h>
#endif
@@ -30,6 +34,9 @@
/* Size of zlib buffer for .tar.gz */
#define ZLIB_OUT_SIZE 4096
+/* Size of lz4 input chunk for .lz4 */
+#define LZ4_IN_SIZE 4096
+
/*-------------------------------------------------------------------------
* WalDirectoryMethod - write wal to a directory looking like pg_wal
*-------------------------------------------------------------------------
@@ -41,6 +48,7 @@
typedef struct DirectoryMethodData
{
char *basedir;
+ WalCompressionMethod compression_method;
int compression;
bool sync;
} DirectoryMethodData;
@@ -59,6 +67,11 @@ typedef struct DirectoryMethodFile
#ifdef HAVE_LIBZ
gzFile gzfp;
#endif
+#ifdef HAVE_LIBLZ4
+ LZ4F_compressionContext_t ctx;
+ size_t lz4bufsize;
+ void *lz4buf;
+#endif
} DirectoryMethodFile;
static const char *
@@ -74,7 +87,9 @@ dir_get_file_name(const char *pathname, const char *temp_suffix)
char *filename = pg_malloc0(MAXPGPATH * sizeof(char));
snprintf(filename, MAXPGPATH, "%s%s%s",
- pathname, dir_data->compression > 0 ? ".gz" : "",
+ pathname,
+ dir_data->compression_method == COMPRESSION_ZLIB ? ".gz" :
+ dir_data->compression_method == COMPRESSION_LZ4 ? ".lz4" : "",
temp_suffix ? temp_suffix : "");
return filename;
@@ -90,6 +105,11 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
#ifdef HAVE_LIBZ
gzFile gzfp = NULL;
#endif
+#ifdef HAVE_LIBLZ4
+ LZ4F_compressionContext_t ctx = NULL;
+ size_t lz4bufsize = 0;
+ void *lz4buf = NULL;
+#endif
filename = dir_get_file_name(pathname, temp_suffix);
snprintf(tmppath, sizeof(tmppath), "%s/%s",
@@ -107,7 +127,7 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
return NULL;
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
{
gzfp = gzdopen(fd, "wb");
if (gzfp == NULL)
@@ -124,9 +144,59 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
}
}
#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ LZ4F_preferences_t lz4preferences = {0};
+ size_t ctx_out;
+ size_t header_size;
+
+ /*
+ * Set all the preferences to default but do note contentSize. It will
+ * be needed in FindStreamingStart.
+ */
+ memset(&lz4preferences, 0, sizeof(LZ4F_frameInfo_t));
+ lz4preferences.frameInfo.contentSize = (unsigned long long) WalSegSz;
+ ctx_out = LZ4F_createCompressionContext(&ctx, LZ4F_VERSION);
+ lz4bufsize = LZ4F_compressBound(LZ4_IN_SIZE, &lz4preferences);
+ if (LZ4F_isError(ctx_out))
+ {
+ close(fd);
+ return NULL;
+ }
+
+ lz4buf = pg_malloc0(lz4bufsize);
+
+ /* add the header */
+ header_size = LZ4F_compressBegin(ctx, lz4buf, lz4bufsize, &lz4preferences);
+ if (LZ4F_isError(header_size))
+ {
+ pg_free(lz4buf);
+ close(fd);
+ return NULL;
+ }
+
+ errno = 0;
+ if (write(fd, lz4buf, header_size) != header_size)
+ {
+ int save_errno = errno;
+
+ (void) LZ4F_compressEnd(ctx, lz4buf, lz4bufsize, NULL);
+ (void) LZ4F_freeCompressionContext(ctx);
+ pg_free(lz4buf);
+ close(fd);
+
+ /*
+ * If write didn't set errno, assume problem is no disk space.
+ */
+ errno = save_errno ? save_errno : ENOSPC;
+ return NULL;
+ }
+ }
+#endif
/* Do pre-padding on non-compressed files */
- if (pad_to_size && dir_data->compression == 0)
+ if (pad_to_size && dir_data->compression_method == COMPRESSION_NONE)
{
PGAlignedXLogBlock zerobuf;
int bytes;
@@ -171,9 +241,19 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
fsync_parent_path(tmppath) != 0)
{
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
gzclose(gzfp);
else
+#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ (void) LZ4F_compressEnd(ctx, lz4buf, lz4bufsize, NULL);
+ (void) LZ4F_freeCompressionContext(ctx);
+ pg_free(lz4buf);
+ close(fd);
+ }
+ else
#endif
close(fd);
return NULL;
@@ -182,9 +262,18 @@ dir_open_for_write(const char *pathname, const char *temp_suffix, size_t pad_to_
f = pg_malloc0(sizeof(DirectoryMethodFile));
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
f->gzfp = gzfp;
#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ f->ctx = ctx;
+ f->lz4buf = lz4buf;
+ f->lz4bufsize = lz4bufsize;
+ }
+#endif
+
f->fd = fd;
f->currpos = 0;
f->pathname = pg_strdup(pathname);
@@ -204,9 +293,46 @@ dir_write(Walfile f, const void *buf, size_t count)
Assert(f != NULL);
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
r = (ssize_t) gzwrite(df->gzfp, buf, count);
else
+#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ size_t chunk;
+ size_t remaining;
+ const void *inbuf = buf;
+
+ remaining = count;
+ while (remaining > 0)
+ {
+ size_t compressed;
+
+ if (remaining > LZ4_IN_SIZE)
+ chunk = LZ4_IN_SIZE;
+ else
+ chunk = remaining;
+
+ remaining -= chunk;
+ compressed = LZ4F_compressUpdate(df->ctx,
+ df->lz4buf, df->lz4bufsize,
+ inbuf, chunk,
+ NULL);
+
+ if (LZ4F_isError(compressed))
+ return -1;
+
+ if (write(df->fd, df->lz4buf, compressed) != compressed)
+ return -1;
+
+ inbuf = ((char *) inbuf) + chunk;
+ }
+
+ /* Our caller keeps track of the uncompressed size. */
+ r = (ssize_t) count;
+ }
+ else
#endif
r = write(df->fd, buf, count);
if (r > 0)
@@ -234,9 +360,76 @@ dir_close(Walfile f, WalCloseMethod method)
Assert(f != NULL);
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
r = gzclose(df->gzfp);
else
+#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ size_t compressed;
+
+ /*
+ * When closing an incomplete LZ4 compressed WAL segment file, since
+ * there are no means available to resume in a later stage. The file
+ * should be considered as invalid. Conversely, when closing a complete
+ * WAL segment all the care is taken to close it properly.
+ */
+ if (dir_get_current_pos(f) == WalSegSz)
+ {
+ compressed = LZ4F_compressEnd(df->ctx,
+ df->lz4buf, df->lz4bufsize,
+ NULL);
+
+ if (LZ4F_isError(compressed))
+ return -1;
+
+ if (write(df->fd, df->lz4buf, compressed) != compressed)
+ return -1;
+ }
+ else
+ {
+ /*
+ * Instead of simply preparing the compression context for future
+ * work, a best effort attempt is made to write the file. Any data
+ * still left in the compression buffer is written. The contentSize
+ * information stored in the header is overwritten, for the benefit
+ * of any inspecting application. See FindStreamingStart() for an
+ * example of such a case. No effort is made to verify that the new
+ * header has not overgrown, overwritting existing data.
+ */
+ LZ4F_preferences_t lz4preferences = {0};
+ size_t unused pg_attribute_unused();
+ size_t header_size;
+ off_t curr;
+
+ compressed = LZ4F_flush(df->ctx,
+ df->lz4buf, df->lz4bufsize,
+ NULL);
+
+ unused = write(df->fd, df->lz4buf, compressed);
+
+ header_size = LZ4F_compressBegin(df->ctx,
+ df->lz4buf, df->lz4bufsize,
+ &lz4preferences);
+
+ if ((curr = lseek(df->fd, 0, SEEK_CUR)) < 0 ||
+ lseek(df->fd, 0, SEEK_SET) < 0 ||
+ write(df->fd, df->lz4buf, header_size) != header_size ||
+ lseek(df->fd, curr, SEEK_SET) < 0)
+ return -1;
+
+ compressed = LZ4F_compressEnd(df->ctx,
+ df->lz4buf, df->lz4bufsize,
+ NULL);
+
+ if (LZ4F_isError(compressed))
+ return -1;
+ }
+
+ r = close(df->fd);
+ }
+ else
#endif
r = close(df->fd);
@@ -291,6 +484,12 @@ dir_close(Walfile f, WalCloseMethod method)
}
}
+#ifdef HAVE_LIBLZ4
+ pg_free(df->lz4buf);
+ /* supports free on NULL */
+ LZ4F_freeCompressionContext(df->ctx);
+#endif
+
pg_free(df->pathname);
pg_free(df->fullpath);
if (df->temp_suffix)
@@ -309,12 +508,27 @@ dir_sync(Walfile f)
return 0;
#ifdef HAVE_LIBZ
- if (dir_data->compression > 0)
+ if (dir_data->compression_method == COMPRESSION_ZLIB)
{
if (gzflush(((DirectoryMethodFile *) f)->gzfp, Z_SYNC_FLUSH) != Z_OK)
return -1;
}
#endif
+#ifdef HAVE_LIBLZ4
+ if (dir_data->compression_method == COMPRESSION_LZ4)
+ {
+ DirectoryMethodFile *df = (DirectoryMethodFile *) f;
+ size_t compressed;
+
+ /* Flush any internal buffers */
+ compressed = LZ4F_flush(df->ctx, df->lz4buf, df->lz4bufsize, NULL);
+ if (LZ4F_isError(compressed))
+ return -1;
+
+ if (write(df->fd, df->lz4buf, compressed) != compressed)
+ return -1;
+ }
+#endif
return fsync(((DirectoryMethodFile *) f)->fd);
}
@@ -334,10 +548,10 @@ dir_get_file_size(const char *pathname)
return statbuf.st_size;
}
-static int
-dir_compression(void)
+static WalCompressionMethod
+dir_compression_method(void)
{
- return dir_data->compression;
+ return dir_data->compression_method;
}
static bool
@@ -373,7 +587,9 @@ dir_finish(void)
WalWriteMethod *
-CreateWalDirectoryMethod(const char *basedir, int compression, bool sync)
+CreateWalDirectoryMethod(const char *basedir,
+ WalCompressionMethod compression_method,
+ int compression, bool sync)
{
WalWriteMethod *method;
@@ -383,7 +599,7 @@ CreateWalDirectoryMethod(const char *basedir, int compression, bool sync)
method->get_current_pos = dir_get_current_pos;
method->get_file_size = dir_get_file_size;
method->get_file_name = dir_get_file_name;
- method->compression = dir_compression;
+ method->compression_method = dir_compression_method;
method->close = dir_close;
method->sync = dir_sync;
method->existsfile = dir_existsfile;
@@ -391,6 +607,7 @@ CreateWalDirectoryMethod(const char *basedir, int compression, bool sync)
method->getlasterror = dir_getlasterror;
dir_data = pg_malloc0(sizeof(DirectoryMethodData));
+ dir_data->compression_method = compression_method;
dir_data->compression = compression;
dir_data->basedir = pg_strdup(basedir);
dir_data->sync = sync;
@@ -424,6 +641,7 @@ typedef struct TarMethodData
{
char *tarfilename;
int fd;
+ WalCompressionMethod compression_method;
int compression;
bool sync;
TarMethodFile *currentfile;
@@ -731,10 +949,10 @@ tar_get_file_size(const char *pathname)
return -1;
}
-static int
-tar_compression(void)
+static WalCompressionMethod
+tar_compression_method(void)
{
- return tar_data->compression;
+ return tar_data->compression_method;
}
static off_t
@@ -1031,8 +1249,16 @@ tar_finish(void)
return true;
}
+/*
+ * The argument compression_method is currently ignored. It is in place for
+ * symmetry with CreateWalDirectoryMethod which uses it for distinguishing
+ * between the different compression methods. CreateWalTarMethod and its family
+ * of functions handle only zlib compression.
+ */
WalWriteMethod *
-CreateWalTarMethod(const char *tarbase, int compression, bool sync)
+CreateWalTarMethod(const char *tarbase,
+ WalCompressionMethod compression_method,
+ int compression, bool sync)
{
WalWriteMethod *method;
const char *suffix = (compression != 0) ? ".tar.gz" : ".tar";
@@ -1043,7 +1269,7 @@ CreateWalTarMethod(const char *tarbase, int compression, bool sync)
method->get_current_pos = tar_get_current_pos;
method->get_file_size = tar_get_file_size;
method->get_file_name = tar_get_file_name;
- method->compression = tar_compression;
+ method->compression_method = tar_compression_method;
method->close = tar_close;
method->sync = tar_sync;
method->existsfile = tar_existsfile;
@@ -1054,6 +1280,7 @@ CreateWalTarMethod(const char *tarbase, int compression, bool sync)
tar_data->tarfilename = pg_malloc0(strlen(tarbase) + strlen(suffix) + 1);
sprintf(tar_data->tarfilename, "%s%s", tarbase, suffix);
tar_data->fd = -1;
+ tar_data->compression_method = compression_method;
tar_data->compression = compression;
tar_data->sync = sync;
#ifdef HAVE_LIBZ
diff --git a/src/bin/pg_basebackup/walmethods.h b/src/bin/pg_basebackup/walmethods.h
index 4abdfd8333..3e378c87b6 100644
--- a/src/bin/pg_basebackup/walmethods.h
+++ b/src/bin/pg_basebackup/walmethods.h
@@ -19,6 +19,13 @@ typedef enum
CLOSE_NO_RENAME
} WalCloseMethod;
+typedef enum
+{
+ COMPRESSION_LZ4,
+ COMPRESSION_ZLIB,
+ COMPRESSION_NONE
+} WalCompressionMethod;
+
/*
* A WalWriteMethod structure represents the different methods used
* to write the streaming WAL as it's received.
@@ -58,8 +65,8 @@ struct WalWriteMethod
*/
char *(*get_file_name) (const char *pathname, const char *temp_suffix);
- /* Return the level of compression */
- int (*compression) (void);
+ /* Returns the compression method */
+ WalCompressionMethod (*compression_method) (void);
/*
* Write count number of bytes to the file, and return the number of bytes
@@ -95,8 +102,11 @@ struct WalWriteMethod
* not all those required for pg_receivewal)
*/
WalWriteMethod *CreateWalDirectoryMethod(const char *basedir,
+ WalCompressionMethod compression_method,
int compression, bool sync);
-WalWriteMethod *CreateWalTarMethod(const char *tarbase, int compression, bool sync);
+WalWriteMethod *CreateWalTarMethod(const char *tarbase,
+ WalCompressionMethod compression_method,
+ int compression, bool sync);
/* Cleanup routines for previously-created methods */
void FreeWalDirectoryMethod(void);
diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list
index 7bbbb34e2f..da6ac8ed83 100644
--- a/src/tools/pgindent/typedefs.list
+++ b/src/tools/pgindent/typedefs.list
@@ -2858,6 +2858,7 @@ WaitEventTimeout
WaitPMResult
WalCloseMethod
WalCompression
+WalCompressionMethod
WalLevel
WalRcvData
WalRcvExecResult
--
2.25.1
