So, today, I did the following:
- Swapped out the 5410's (2.3Ghz) for 5470's (3.33Ghz)
- Set the ext4 mount options to be noatime,barrier=0,data=writeback
- Installed PG 9.1 from the yum repo
Item one:
With the accelerator cache set to 0/100 (all 512MB for writing), loading the db / creating the indexes was about 8 minutes faster. Was hoping for more, but didn't get it. If I split the CREATE INDEXes into separate psql instances, will that be done in parallel?
Item two:
I'm still getting VERY strange results in my SELECT queries.
For example, on the new server:
Same query on the live / old server:
Both of these servers have the same indexes, and almost identical data. However, the old server is doing some different planning than the new server.
What did I switch (or should I unswitch)?
--
Anthony
On Sun, Sep 11, 2011 at 9:12 PM, Alan Hodgson
<ahodgson@simkin.ca> wrote:
On September 11, 2011 03:44:34 PM Anthony Presley wrote:
> First thing I noticed is that it takes the same amount of time to load the
> db (about 40 minutes) on the new hardware as the old hardware. I was
> really hoping with the faster, additional drives and a hardware RAID
> controller, that this would be faster. The database is only about 9GB
> with pg_dump (about 28GB with indexes).
Loading the DB is going to be CPU-bound (on a single) core, unless your disks
really suck, which they don't. Most of the time will be spent building
indexes.
I don't know offhand why the queries are slower, though, unless you're not
getting as much cached before testing as on the older box.
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