so from the much-loved
https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server page, we
have this:
"
PostgreSQL can only safely use a write cache if it has a battery backup.
See WAL reliability for an essential introduction to this topic. No,
really; go read that right now, it's vital to understand that if you
want your database to work right.
...
For situations where a small amount of data loss is acceptable in return
for a large boost in how many updates you can do to the database per
second, consider switching synchronous commit off. This is particularly
useful in the situation where you do not have a battery-backed write
cache on your disk controller, because you could potentially get
thousands of commits per second instead of just a few hundred.
...
"
My question is-- does it make sense to switch synchronous commit off for
EBS-backed EC2 instances running postgresql at Amazon? Has anyone done
any benchmarking of this change on AWS? Since EBS is a "black box" to us
as end users, I have no clue what type of caching- volatile or not-- may
be going on behind the scenes.
--
Larry J. Prikockis
System Administrator
240-965-4597 (direct)
lprikockis@vecna.com
http://www.vecna.com
Vecna Technologies, Inc.
6404 Ivy Lane Suite 500
Greenbelt, MD 20770
Phone: (240) 965-4500
Fax: (240) 547-6133
Better Technology, Better World (TM)
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