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Make pg_receivexlog and pg_basebackup -X stream work across timeline switches.

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This mirrors the changes done earlier to the server in standby mode. When
receivelog reaches the end of a timeline, as reported by the server, it
fetches the timeline history file of the next timeline, and restarts
streaming from the new timeline by issuing a new START_STREAMING command.

When pg_receivexlog crosses a timeline, it leaves the .partial suffix on the
last segment on the old timeline. This helps you to tell apart a partial
segment left in the directory because of a timeline switch, and a completed
segment. If you just follow a single server, it won't make a difference, but
it can be significant in more complicated scenarios where new WAL is still
generated on the old timeline.

This includes two small changes to the streaming replication protocol:
First, when you reach the end of timeline while streaming, the server now
sends the TLI of the next timeline in the server's history to the client.
pg_receivexlog uses that as the next timeline, so that it doesn't need to
parse the timeline history file like a standby server does. Second, when
BASE_BACKUP command sends the begin and end WAL positions, it now also sends
the timeline IDs corresponding the positions.
This commit is contained in:
Heikki Linnakangas
2013-01-17 20:23:00 +02:00
parent 8ae35e9180
commit 0b6329130e
12 changed files with 699 additions and 312 deletions
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14
src/backend/access/transam/timeline.c
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@@ -545,22 +545,26 @@ tliOfPointInHistory(XLogRecPtr ptr, List *history)
}
/*
* Returns the point in history where we branched off the given timeline.
* Returns InvalidXLogRecPtr if the timeline is current (= we have not
* branched off from it), and throws an error if the timeline is not part of
* this server's history.
* Returns the point in history where we branched off the given timeline,
* and the timeline we branched to (*nextTLI). Returns InvalidXLogRecPtr if
* the timeline is current, ie. we have not branched off from it, and throws
* an error if the timeline is not part of this server's history.
*/
XLogRecPtr
tliSwitchPoint(TimeLineID tli, List *history)
tliSwitchPoint(TimeLineID tli, List *history, TimeLineID *nextTLI)
{
ListCell *cell;
if (nextTLI)
*nextTLI = 0;
foreach (cell, history)
{
TimeLineHistoryEntry *tle = (TimeLineHistoryEntry *) lfirst(cell);
if (tle->tli == tli)
return tle->end;
if (nextTLI)
*nextTLI = tle->tli;
}
ereport(ERROR,