Re: Performance Issues

["Mark Woodward" <pgsql(at)mohawksoft(dot)com>]

> Dhanaraj M wrote:
>> I have the following doubts.
>>
>> 1. Does postgres create an index on every primary key?  Usually, queries
>> are performed against a table on the primary key, so, an index on it
>> will be very useful.
>
> Yes, a unique index is used to enforce the primary-key.

Well, here is an interesting question that I have suddenly become very
curious of, if you have a primary key, obviously a unique index, is it, in
fact, use this index regardless of analyzing the table?


>
>> 2. If 'm executing a complex query and it takes 10 seconds to return the
>> results -- it takes 10 seconds to execute the next time also.  I'm
>> wondering if there's any kind of caching that can be enabled -- so, the
>> next time it takes <10 seconds to return the results.
>
> Not of query results. Obviously data itself might be cached. You might
> want to look at memcached for this sort of thing.


I am looking at this string of posts and it occurs to me that he should
run analyze. Maybe I'm jumping at the wrong point.