On 2020-09-09 20:29, Fujii Masao wrote:
On 2020/09/09 2:00, Alexey Kondratov wrote:
According to the Sawada-san's v25 0002 the logic is pretty much the
same there:
+2. Pre-Commit phase (1st phase of two-phase commit)
+3. Commit locally
+Once we've prepared all of them, commit the transaction locally.
+4. Post-Commit Phase (2nd phase of two-phase commit)
Brief look at the code confirms this scheme. IIUC, AtEOXact_FdwXact /
FdwXactParticipantEndTransaction happens after
ProcArrayEndTransaction() in the CommitTransaction(). Thus, I don't
see many difference between these approach and CallXactCallbacks()
usage regarding this point.
IIUC the commit logic in Sawada-san's patch looks like
1. PreCommit_FdwXact()
PREPARE TRANSACTION command is issued
2. RecordTransactionCommit()
2-1. WAL-log the commit record
2-2. Update CLOG
2-3. Wait for sync rep
2-4. FdwXactWaitForResolution()
Wait until COMMIT PREPARED commands are issued to the
remote servers and completed.
3. ProcArrayEndTransaction()
4. AtEOXact_FdwXact(true)
So ISTM that the timing of when COMMIT PREPARED is issued
to the remote server is different between the patches.
Am I missing something?
No, you are right, sorry. At a first glance I thought that
AtEOXact_FdwXact is responsible for COMMIT PREPARED as well, but it is
only calling FdwXactParticipantEndTransaction in the abort case.
Regards
--
Alexey Kondratov
Postgres Professional https://www.postgrespro.com
Russian Postgres Company
