As promised, I did a tiny benchmark - basically, 8 empty tables are
filled with 100k rows each within 8 transactions (somewhat typically for
my application). The test machine has 4 cores, 64G RAM and RAID1 10k
drives for data.
# INSERTs into a TEMPORARY table:
[joac...@testsrv scaling]$
Am 02.06.2010 12:03, schrieb Pierre C:
Usually WAL causes a much larger performance hit than this.
Since the following command :
CREATE TABLE tmp AS SELECT n FROM generate_series(1,100) AS n
which inserts 1M rows takes 1.6 seconds on my desktop, your 800k rows
INSERT taking more than 3
On 05/26/2010 06:03 PM, Joachim Worringen wrote:
Am 25.05.2010 12:41, schrieb Andres Freund:
On Tuesday 25 May 2010 11:00:24 Joachim Worringen wrote:
Thanks. So, the Write-Ahead-Logging (being used or not) does not matter?
It does matter quite significantly in my experience. Both from an io
On Fri, May 28, 2010 at 4:04 AM, Joachim Worringen
joachim.worrin...@iathh.de wrote:
On 05/26/2010 06:03 PM, Joachim Worringen wrote:
Am 25.05.2010 12:41, schrieb Andres Freund:
On Tuesday 25 May 2010 11:00:24 Joachim Worringen wrote:
Thanks. So, the Write-Ahead-Logging (being used or not)
Am 25.05.2010 12:41, schrieb Andres Freund:
On Tuesday 25 May 2010 11:00:24 Joachim Worringen wrote:
Thanks. So, the Write-Ahead-Logging (being used or not) does not matter?
It does matter quite significantly in my experience. Both from an io and a cpu
overhead perspective.
O.k., looks as if
WAL matters in performance. Hence why it is advisable to have it on a
separate drive :)
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Greetings,
in
http://archives.postgresql.org/message-id/1056648218.7041.11.ca...@jester,
it is stated that the performance of temporary tables is the same as a
regular table but without
WAL on the table contents..
I have a datamining-type application which makes heavy use of temporary
temporary tables are handled pretty much like the regular table. The
magic happens on schema level, new schema is setup for connection, so
that it can access its own temporary tables.
Temporary tables also are not autovacuumed.
And that's pretty much the most of the differences.
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Am 25.05.2010 10:49, schrieb Grzegorz Jaśkiewicz:
temporary tables are handled pretty much like the regular table. The
magic happens on schema level, new schema is setup for connection, so
that it can access its own temporary tables.
Temporary tables also are not autovacuumed.
And that's pretty
2010/5/25 Joachim Worringen joachim.worrin...@iathh.de:
Am 25.05.2010 10:49, schrieb Grzegorz Jaśkiewicz:
temporary tables are handled pretty much like the regular table. The
magic happens on schema level, new schema is setup for connection, so
that it can access its own temporary tables.
Am 25.05.2010 11:15, schrieb Thom Brown:
2010/5/25 Joachim Worringenjoachim.worrin...@iathh.de:
And, is there anything like RAM-only tables? I really don't care whether the
staging data is lost on the rare event of a machine crash, or whether the
query crashes due to lack of memory (I make sure
WAL does the same thing to DB journaling does to the FS.
Plus allows you to roll back (PITR).
As for the RAM, it will be in ram as long as OS decides to keep it in
RAM cache, and/or its in the shared buffers memory.
Unless you have a lot of doubt about the two, I don't think it makes
too much
Am 25.05.2010 11:38, schrieb Grzegorz Jaśkiewicz:
WAL does the same thing to DB journaling does to the FS.
Plus allows you to roll back (PITR).
As for the RAM, it will be in ram as long as OS decides to keep it in
RAM cache, and/or its in the shared buffers memory.
Or until I commit the
On Tuesday 25 May 2010 11:00:24 Joachim Worringen wrote:
Am 25.05.2010 10:49, schrieb Grzegorz Jaśkiewicz:
temporary tables are handled pretty much like the regular table. The
magic happens on schema level, new schema is setup for connection, so
that it can access its own temporary tables.
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