Report WAL flush, not insert, position in replication IDENTIFY_SYSTEM

When beginning streaming replication, the client usually issues the
IDENTIFY_SYSTEM command, which used to return the current WAL insert
position. That's not suitable for the intended purpose of that field,
however. pg_receivexlog uses it to start replication from the reported
point, but if it hasn't been flushed to disk yet, it will fail. Change
IDENTIFY_SYSTEM to report the flush position instead.

Backpatch to 9.1 and above. 9.0 doesn't report any WAL position.
This commit is contained in:
Heikki Linnakangas 2015-02-06 11:18:14 +02:00
parent 5ee5bc3873
commit ff16b40f8c
2 changed files with 2 additions and 2 deletions

View File

@ -1371,7 +1371,7 @@ The commands accepted in walsender mode are:
</term> </term>
<listitem> <listitem>
<para> <para>
Current xlog write location. Useful to get a known location in the Current xlog flush location. Useful to get a known location in the
transaction log where streaming can start. transaction log where streaming can start.
</para> </para>
</listitem> </listitem>

View File

@ -316,7 +316,7 @@ IdentifySystem(void)
logptr = GetStandbyFlushRecPtr(); logptr = GetStandbyFlushRecPtr();
} }
else else
logptr = GetInsertRecPtr(); logptr = GetFlushRecPtr();
snprintf(tli, sizeof(tli), "%u", ThisTimeLineID); snprintf(tli, sizeof(tli), "%u", ThisTimeLineID);