Thank you for your help. I found that an implicit index is created for
the primary key in the current version. However, it is not done in 7.x
version.
Mark Woodward wrote:
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.
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