[Bucardo-general] Latency on delete
Alex Balashov
abalashov at evaristesys.com
Fri Jan 17 15:15:20 UTC 2014
Hi,
How long is a DELETE of ~4.5 million rows (in a relatively narrow table)
supposed to take in a scenario with a simple pushdelta replication
setup? Mine took 1 hour and 45 minutes. While I realise that Bucardo's
row level-trigger based system incurs some additional latency, the
latency is just inserting those deltas, by and large, right? It
shouldn't take quite so long as that, I would hypothesise.
Both databases - including the 'bucardo' schema of the source - are
tidily vacuumed nightly.
The servers are both quad-core 2 GHz Xeons with 32 GB of RAM each with
decent SATA drives on a Dell PERC.
In addition, the following PostgreSQL tuning measures are in place:
shared_buffers = 512 MB
work_mem = 1024MB
wal_level = minimal
fsync = off
synchronous_commit = off
The 'bucardo_ctl status' output does not show any delays, failures or
other anomalies.
The table on which I ran the DELETE statement had about 38 million rows,
of which I was attempting to delete 4.5. The table also has two indexes
(primary key index and one additional indexed column) and a foreign key
constraint.
Is it reasonable and expected for this DELETE to have taken close to two
hours?
Thank much!
-- Alex
--
Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
Suite 106
Decatur, GA 30030
United States
Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com/
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