From: | Sezai YILMAZ <sezai(dot)yilmaz(at)pro-g(dot)com(dot)tr> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Subject: | Re: PostgreSQL insert speed tests |
Date: | 2004-02-28 08:29:56 |
Message-ID: | 40405184.8060700@pro-g.com.tr |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Tom Lane wrote:
>Sezai YILMAZ <sezai(dot)yilmaz(at)pro-g(dot)com(dot)tr> writes:
>
>
>>I changed the three hash indexes to btree.
>>The performance is increased about 2 times (in PostgreSQL 7.3.4 1905
>>rows/s).
>>Concurrent inserts now work.
>>
>>
>Concurrent inserts should work with hash indexes in 7.4, though not 7.3.
>
>
I notice this condition. I do not get dead locks with 7.4 on schema with
hash indexes. 7.4 solves this problem but is very slow.
>The slowdown you report probably is due to the rewrite of hash indexing
>to allow more concurrency --- the locking algorithm is more complex than
>it used to be. I am surprised that the effect is so large though.
>Could you make your test program available?
>
>
The test program and .SQL script is attached
Comiple and link scenarios:
without transactions (where each insert is a transaction)
$ gcc -o tester tester.c -lpq
with default 400 inserts per transaction blocks
$ gcc -DTRANSACTION -o tester tester.c -lpq
with 200 inserts per transaction blocks
$ gcc -DTRANSACTION -DINSERTPERTRANSACTION=200 -o tester tester.c -lpq
I do concurrent tests by starting seperate tester programs from
different xterm windows.
>>Changed indexes are more suitable for hash type.
>>
>>
>
>Are they? How many distinct values are there in those columns?
>I suspect that your test may be stressing the case where only a few hash
>buckets are used and each bucket chain gets to be very long.
>
>
The biggest one gets 200 distinct values, the others are 5, and 10. More
information is in "tester.c" where INSERT query string is built.
Regards,
-sezai
Attachment | Content-Type | Size |
---|---|---|
schema.sql | text/x-sql | 626 bytes |
tester.c | text/x-c | 3.7 KB |
From | Date | Subject | |
---|---|---|---|
Next Message | Rajat Katyal | 2004-02-28 08:36:54 | Re: value too long error |
Previous Message | Uwe C. Schroeder | 2004-02-28 07:16:42 | Re: value too long error |