On 30.11.2018 15:10, Dmitry Dolgov wrote:
Thank you. I played a bit with this patch, and can confirm visible WAL size
reduction (it's rather obvious, but still). Although, probably due to lack of
my knowledge here, I wonder how does it work when an index is build
concurrently?
Routine generate_xlog_for_rel() works only at phase 2 of concurrent
index building.
At the phase 3, during validate_index() execution we use aminsert() ->
PlaceToPage() mechanism as before the patch.
In the concurrent mode, I do not expect any problems, caused by the patch.
Benchmarks:
-----------
Test: pgbench -f gin-WAL-test.sql -t 5:
---------------------------------------
master:
Latency average: 27696.299 ms
WAL size: 2.66 GB
Does it makes sense to measure latency of the entire script, since it contains
also some preparation work? Of course it still shows the difference between
patched version and master, but probably in a more noisy way.
Ok. It is used only for demonstration.
--
Andrey Lepikhov
Postgres Professional
https://postgrespro.com
The Russian Postgres Company
