Re: [HACKERS] Proposal: pg_rewind to skip config files

5 сент. 2017 г., в 15:42, Chris Travers <chris.travers@adjust.com> написал(а):

On Tue, Sep 5, 2017 at 2:40 PM, Vladimir Borodin <root@simply.name> wrote:

5 сент. 2017 г., в 14:04, Michael Paquier <michael.paquier@gmail.com> написал(а):

For example, in archive_command we put WALs for archiving from
pg_xlog/pg_wal into another directory inside PGDATA and than another cron
task makes real archiving. This directory ideally should be skipped by
pg_rewind, but it would not be handled by proposed change.

I would be curious to follow the reasoning for such a two-phase
archiving (You basically want to push it in two places, no? But why
not just use pg_receivexlog then?). This is complicated to handle from
the point of view of availability and backup reliability + durability.

We do compress WALs and send them over network. Doing it via archive_command in single thread is sometimes slower than new WALs are written under heavy load.

How would this work when it comes to rewinding against a file directory?