On 01/03/2015 12:28 AM, Josh Berkus wrote:
On 01/02/2015 01:57 AM, Heikki Linnakangas wrote:
wal_keep_segments does not affect the calculation of CheckPointSegments.
If you set wal_keep_segments high enough, checkpoint_wal_size will be
exceeded. The other alternative would be to force a checkpoint earlier,
i.e. lower CheckPointSegments, so that checkpoint_wal_size would be
honored. However, if you set wal_keep_segments high enough, higher than
checkpoint_wal_size, it's impossible to honor checkpoint_wal_size no
matter how frequently you checkpoint.
So you're saying that wal_keep_segments is part of the max_wal_size
total, NOT in addition to it?
Not sure what you mean. wal_keep_segments is an extra control that can
prevent WAL segments from being recycled. It has the same effect as
archive_command failing for N most recent segments, if that helps.
Just asking for clarification, here. I think that's a fine idea, I just
want to make sure I understood you. The importance of wal_keep_segments
will be fading as more people use replication slots.
Yeah.
- Heikki
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