On Fri, May 11, 2018 at 12:09:58PM -0300, Alvaro Herrera wrote: > Yeah, I had this exact comment, but I was unable to come up with a test > case that would cause a problem.
pg_ctl promote would wait for the control file to be updated, so you cannot use it in the TAP tests to trigger the promotion. Still I think I found one after waking up? Please note I have not tested it: - Use a custom trigger file and then trigger promotion with a signal. - Use a sleep command in recovery_end_command to increase the window, as what matters is sleeping after CreateEndOfRecoveryRecord updates the control file. - Issue a restart point on the standby, which will update the control file. - Stop the standby with immediate mode. - Start the standby, it should see unreferenced pages. > Hmm. Can we change the control file in released branches? (It should > be possible to make the new server understand both old and new formats, > but I think this is breaking new ground and it looks easy to introduce > more bugs there.) We definitely can't, even if the new value is added at the end of DBState :( A couple of wild ideas, not tested, again after waking up: 1) We could also abuse of existing values by using the existing DB_IN_CRASH_RECOVERY or DB_STARTUP. Still that's not completely true as the cluster may be open for business as a hot standby. 2) Invent a new special value for XLogRecPtr, normally impossible to reach, which uses high bits. -- Michael
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