> 12 июня 2017 г., в 13:19, Amit Kapila <amit.kapil...@gmail.com> написал(а): > > On Sun, Jun 11, 2017 at 11:59 PM, Vladimir Borodin <r...@simply.name > <mailto:r...@simply.name>> wrote: >> >> 8 июня 2017 г., в 17:03, Amit Kapila <amit.kapil...@gmail.com> написал(а): >> >> On Thu, Jun 8, 2017 at 6:49 PM, Dmitriy Sarafannikov >> <dsarafanni...@yandex.ru> wrote: >> >> >> Why didn't rsync made the copies on master and replica same? >> >> >> Because rsync was running with —size-only flag. >> >> >> IIUC the situation, the new WAL and updated pg_control file has been >> copied, but not updated data files due to which the WAL has not been >> replayed on replicas? If so, why the pg_control file is copied, it's >> size shouldn't have changed? >> >> >> Because on master pg_upgrade moves $prefix/9.5/data/global/pg_control to >> $prefix/9.5/data/global/pg_control.old and creates new >> $prefix/9.6/data/global/pg_control without making hardlink. When running >> rsync from master to replica rsync sees $prefix/9.6/data/global/pg_control >> on master and checks if it is a hardlink. Since it is not a hardlink and >> $prefix/9.6/data/global/pg_control does not exist on replica rsync copies >> it. For data files the logic is different since they are hardlinks, >> corresponding files exist on replica and they are the same size. >> > > Okay, in that case, I guess it is better to run Analyze on master > after the upgrade is complete (including an upgrade for replicas). If > you are worried about the performance of read-only replicas till the > time Analyze on the master in completed, you might want to use > --analyze-in-stages of vaccumdb and or use (-j njobs) along with it to > parallelize the operation.
What about the following sequence? 1. Run pg_upgrade on master, 2. Start it in single-user mode and stop (to get right wal_level in pg_control), 3. Copy pg_control somewhere, 4. Start master, run analyze and stop. 5. Put the control file from step 3 to replicas and rsync them according to the documentation. And I think that step 10.f in the documentation [1] should be fixed to mention starting in single-user mode or with disabled autovacuum. [1] https://www.postgresql.org/docs/devel/static/pgupgrade.html > > > -- > With Regards, > Amit Kapila. > EnterpriseDB: http://www.enterprisedb.com <http://www.enterprisedb.com/> -- May the force be with you… https://simply.name
