On Tue, Apr 21, 2020 at 03:08:30PM +0900, Kyotaro Horiguchi wrote: > The commit a7e8ece41c adds a new member restoreCommand to > XLogPageReadPrivate. readOneRecord doesn't make use of it but forgets > to set NULL. That can lead to illegal pointer access.
That's an oversight of the original commit. Now, instead of failing even if there is a restore command, wouldn't it be better to pass down the restore_command to readOneRecord() so as we can optionally improve the stability of a single record lookup? This only applies to a checkpoint record now, but this routine could be called elsewhere in the future. Please see the attached. -- Michael
diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c
index 14a5db5433..c51b5db315 100644
--- a/src/bin/pg_rewind/parsexlog.c
+++ b/src/bin/pg_rewind/parsexlog.c
@@ -106,7 +106,8 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, int tliIndex,
* doing anything with the record itself.
*/
XLogRecPtr
-readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex)
+readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex,
+ const char *restoreCommand)
{
XLogRecord *record;
XLogReaderState *xlogreader;
@@ -115,6 +116,7 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, int tliIndex)
XLogRecPtr endptr;
private.tliIndex = tliIndex;
+ private.restoreCommand = restoreCommand;
xlogreader = XLogReaderAllocate(WalSegSz, datadir, &SimpleXLogPageRead,
&private);
if (xlogreader == NULL)
diff --git a/src/bin/pg_rewind/pg_rewind.c b/src/bin/pg_rewind/pg_rewind.c
index 101f0911be..633955f7be 100644
--- a/src/bin/pg_rewind/pg_rewind.c
+++ b/src/bin/pg_rewind/pg_rewind.c
@@ -339,7 +339,8 @@ main(int argc, char **argv)
/* Read the checkpoint record on the target to see where it ends. */
chkptendrec = readOneRecord(datadir_target,
ControlFile_target.checkPoint,
- targetNentries - 1);
+ targetNentries - 1,
+ restore_command);
/*
* If the histories diverged exactly at the end of the shutdown
diff --git a/src/bin/pg_rewind/pg_rewind.h b/src/bin/pg_rewind/pg_rewind.h
index b122ae43e5..5cf5f17bb5 100644
--- a/src/bin/pg_rewind/pg_rewind.h
+++ b/src/bin/pg_rewind/pg_rewind.h
@@ -50,7 +50,7 @@ extern void findLastCheckpoint(const char *datadir, XLogRecPtr searchptr,
XLogRecPtr *lastchkptredo,
const char *restoreCommand);
extern XLogRecPtr readOneRecord(const char *datadir, XLogRecPtr ptr,
- int tliIndex);
+ int tliIndex, const char *restoreCommand);
/* in pg_rewind.c */
extern void progress_report(bool force);
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