Re: Index Only Scan vs Cache

>On 7/9/2015 12:41 PM, Tom Lane wrote:
>> Andy Colson <andy(at)squeakycode(dot)net> writes:
>>> My question is: Will PG cache only the index (assuming it can always do
>>> an Index Only Scan), or will it cache the table as well?

I'm not sure that indexes on tiny tables are useful.
They raise the options to consider by the query planner, which has its small cost too.
I'd be interested on other opinions on this.
Any rule of the thumb with which number of pages per relation it is worth to start indexing ?

And still another question: I've have tiny static tables too, that never got analyzed.
Can this fool the query planner in a negative way ?

regards,

Marc Mamin

>> The table blocks would fall out of cache if they're never touched.
>>
>> regards, tom lane
>>
>>
>
>Sweet! Thanks Tom.
>
>
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