| From: | Durgaprasad Pawar <durgaprasad(dot)pawar(at)yahoo(dot)co(dot)in> |
|---|---|
| To: | pg novice <pgsql-novice(at)postgresql(dot)org> |
| Subject: | High CPU utilization with various index combinations |
| Date: | 2008-01-16 06:22:23 |
| Message-ID: | 745277.80781.qm@web7707.mail.in.yahoo.com |
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| Thread: | |
| Lists: | pgsql-novice |
Hi,
I have a table with 4 columns (a,b,c,d).
1. Earlier I had defined a UNIQUE constraint on all 4 columns (hence creating a composite index on all 4 columns) and the CPU utilization was ~1/2% during data insertion.
2. However, when I dropped this constraint and created a new UNIQUE constraints on (a,c,d) and (b) the CPU utilization hits 40% during data insertion with same date rate.
3. Also, when I have two unique indexes as (a,b,c,d) and (b) the CPU utilization is very low just like that first case.
Can anyone please explain why there is such a big difference in CPU utilization with different index/constraint combinations?
Regards,
Durgaprasad
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