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pg_rewind: Don't error if the two clusters are already on the same timeline 

This previously resulted in an error and a nonzero exit status, but
after discussion this should rather be a noop with a zero exit status.
This commit is contained in:
Peter Eisentraut 2015-12-03 22:21:16 -05:00
parent 8c1615531f
commit 6b34e55638
2 changed files with 46 additions and 27 deletions
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59
src/bin/pg_rewind/pg_rewind.c
View File

@ -216,41 +216,46 @@ main(int argc, char **argv)
* do.
*/
if (ControlFile_target.checkPointCopy.ThisTimeLineID == ControlFile_source.checkPointCopy.ThisTimeLineID)
pg_fatal("source and target cluster are on the same timeline\n");
findCommonAncestorTimeline(&divergerec, &lastcommontliIndex);
printf(_("servers diverged at WAL position %X/%X on timeline %u\n"),
(uint32) (divergerec >> 32), (uint32) divergerec,
targetHistory[lastcommontliIndex].tli);
/*
* Check for the possibility that the target is in fact a direct ancestor
* of the source. In that case, there is no divergent history in the
* target that needs rewinding.
*/
if (ControlFile_target.checkPoint >= divergerec)
{
rewind_needed = true;
printf(_("source and target cluster are on the same timeline\n"));
rewind_needed = false;
}
else
{
XLogRecPtr chkptendrec;
/* Read the checkpoint record on the target to see where it ends. */
chkptendrec = readOneRecord(datadir_target,
ControlFile_target.checkPoint,
targetNentries - 1);
findCommonAncestorTimeline(&divergerec, &lastcommontliIndex);
printf(_("servers diverged at WAL position %X/%X on timeline %u\n"),
(uint32) (divergerec >> 32), (uint32) divergerec,
targetHistory[lastcommontliIndex].tli);
/*
* If the histories diverged exactly at the end of the shutdown
* checkpoint record on the target, there are no WAL records in the
* target that don't belong in the source's history, and no rewind is
* needed.
* Check for the possibility that the target is in fact a direct ancestor
* of the source. In that case, there is no divergent history in the
* target that needs rewinding.
*/
if (chkptendrec == divergerec)
rewind_needed = false;
else
if (ControlFile_target.checkPoint >= divergerec)
{
rewind_needed = true;
}
else
{
XLogRecPtr chkptendrec;
/* Read the checkpoint record on the target to see where it ends. */
chkptendrec = readOneRecord(datadir_target,
ControlFile_target.checkPoint,
targetNentries - 1);
/*
* If the histories diverged exactly at the end of the shutdown
* checkpoint record on the target, there are no WAL records in the
* target that don't belong in the source's history, and no rewind is
* needed.
*/
if (chkptendrec == divergerec)
rewind_needed = false;
else
rewind_needed = true;
}
}
if (!rewind_needed)

14
src/bin/pg_rewind/t/005_same_timeline.pl Normal file
View File

@ -0,0 +1,14 @@
use strict;
use warnings;
use TestLib;
use Test::More tests => 1;
use RewindTest;
# Test that running pg_rewind if the two clusters are on the same
# timeline runs successfully.
RewindTest::setup_cluster();
RewindTest::start_master();
RewindTest::create_standby();
RewindTest::run_pg_rewind('local');