On Friday, March 18, 2016 4:54 PM, Andreas Kretschmer <andreas@xxxxxxxxxxxxxxx>
wrote:
>
>
>> Paul Jones <pbj@xxxxxxxxxx> hat am 18. Marz 2016 um 21:24 geschrieben:
>>
>>
>> In Postgres 9.5.1 with a shared_buffer cache of 7Gb, a SELECT from
>
> the first query reads only the tuple from heap that are matched the
> where-condition.
> The 2nd query with an other where-condition reads other rows than the first
> query.
>
> Keep in mind: a index search reads the index and pulls the rows that matched
the
> condition from the heap, no more.
Ok, thanks! I understand now!
>
> Regards
> --
> Andreas Kretschmer
> http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
wrote:
>
>
>> Paul Jones <pbj@xxxxxxxxxx> hat am 18. Marz 2016 um 21:24 geschrieben:
>>
>>
>> In Postgres 9.5.1 with a shared_buffer cache of 7Gb, a SELECT from
>
> the first query reads only the tuple from heap that are matched the
> where-condition.
> The 2nd query with an other where-condition reads other rows than the first
> query.
>
> Keep in mind: a index search reads the index and pulls the rows that matched
the
> condition from the heap, no more.
Ok, thanks! I understand now!
>
> Regards
> --
> Andreas Kretschmer
> http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
