Hi all, (Fujii-san and David in CC.) Fujii-san has reported on Twitter that we had better add the TLI number to what pg_waldump --save-fullpage generates for the file names of the blocks, as it could be possible that we overwrite some blocks. This information can be added thanks to ws_tli, that tracks the TLI of the opened segment.
Attached is a patch to fix this issue, adding an open item assigned to me. The file format is documented in the TAP test and the docs, the two only places that would need a refresh. Thoughts or comments? -- Michael
From 35dc549115e8bf054a5f756c652b07f3f49d0bce Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@paquier.xyz>
Date: Tue, 27 Jun 2023 15:04:49 +0900
Subject: [PATCH v1] Add timeline to file names generated with pg_waldump
--save-fullpage
Reported-by: Fujii Masao
---
src/bin/pg_waldump/pg_waldump.c | 3 ++-
src/bin/pg_waldump/t/002_save_fullpage.pl | 9 +++++----
doc/src/sgml/ref/pg_waldump.sgml | 9 ++++++++-
3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index c6d3ae6344..96845e1a1a 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -518,7 +518,8 @@ XLogRecordSaveFPWs(XLogReaderState *record, const char *savepath)
else
pg_fatal("invalid fork number: %u", fork);
- snprintf(filename, MAXPGPATH, "%s/%08X-%08X.%u.%u.%u.%u%s", savepath,
+ snprintf(filename, MAXPGPATH, "%s/%08X-%08X-%08X.%u.%u.%u.%u%s", savepath,
+ record->seg.ws_tli,
LSN_FORMAT_ARGS(record->ReadRecPtr),
rnode.spcOid, rnode.dbOid, rnode.relNumber, blk, forkname);
diff --git a/src/bin/pg_waldump/t/002_save_fullpage.pl b/src/bin/pg_waldump/t/002_save_fullpage.pl
index 831ffdefef..dc53a6f5b4 100644
--- a/src/bin/pg_waldump/t/002_save_fullpage.pl
+++ b/src/bin/pg_waldump/t/002_save_fullpage.pl
@@ -79,15 +79,16 @@ $node->command_ok(
'pg_waldump with --save-fullpage runs');
# This regexp will match filenames formatted as:
-# XXXXXXXX-XXXXXXXX.DBOID.TLOID.NODEOID.dd_fork with the components being:
-# - WAL LSN in hex format,
-# - Tablespace OID (0 for global)
+# TLI-XXXXXXXX-XXXXXXXX.DBOID.TLOID.NODEOID.dd_fork with the components being:
+# - Timeline number in hex format.
+# - WAL LSN in hex format.
+# - Tablespace OID (0 for global).
# - Database OID.
# - Relfilenode.
# - Block number.
# - Fork this block came from (vm, init, fsm, or main).
my $file_re =
- qr/^([0-9A-F]{8})-([0-9A-F]{8})[.][0-9]+[.][0-9]+[.][0-9]+[.][0-9]+(?:_vm|_init|_fsm|_main)?$/;
+ qr/^[0-9A-F]{8}-([0-9A-F]{8})-([0-9A-F]{8})[.][0-9]+[.][0-9]+[.][0-9]+[.][0-9]+(?:_vm|_init|_fsm|_main)?$/;
my $file_count = 0;
diff --git a/doc/src/sgml/ref/pg_waldump.sgml b/doc/src/sgml/ref/pg_waldump.sgml
index e5f9637847..4592d6016a 100644
--- a/doc/src/sgml/ref/pg_waldump.sgml
+++ b/doc/src/sgml/ref/pg_waldump.sgml
@@ -283,7 +283,7 @@ PostgreSQL documentation
</para>
<para>
The full page images are saved with the following file name format:
- <literal><replaceable>LSN</replaceable>.<replaceable>RELTABLESPACE</replaceable>.<replaceable>DATOID</replaceable>.<replaceable>RELNODE</replaceable>.<replaceable>BLKNO</replaceable><replaceable>FORK</replaceable></literal>
+ <literal><replaceable>TIMELINE</replaceable>-<replaceable>LSN</replaceable>.<replaceable>RELTABLESPACE</replaceable>.<replaceable>DATOID</replaceable>.<replaceable>RELNODE</replaceable>.<replaceable>BLKNO</replaceable><replaceable>FORK</replaceable></literal>
The file names are composed of the following parts:
<informaltable>
@@ -296,6 +296,13 @@ PostgreSQL documentation
</thead>
<tbody>
+ <row>
+ <entry>TIMELINE</entry>
+ <entry>The timeline of the WAL segment file where the record
+ is located formatted as one 8-character hexadecimal number
+ <literal>%08X</literal></entry>
+ </row>
+
<row>
<entry>LSN</entry>
<entry>The <acronym>LSN</acronym> of the record with this image,
--
2.40.1
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