Re: Postgres seems to use indexes in the wrong order

On Tue, Jan 27, 2015 at 6:59 AM, Tim Uckun <timuckun(at)gmail(dot)com> wrote:

> The query seems to first use the timestamp column which results in a huge
> number of records and then filters out using the integer and the macaddr
> indices. If it was to use the integer index first it would start with a
> tiny number of records.
>

​May be the record distribution of quantiles is skewed.​ Have you tried to
set more granular statistics for your int column?

The effective_cache_size is one gig. The others are not set so therefore
> the default.

​Ideally the effective_cache_size can be set to as much as 50-60% of your
available memory. Also you need to tune your random_page_cost as per the
behavior of your disk.

https://wiki.postgresql.org/wiki/Tuning_Your_PostgreSQL_Server​

​If these two does not work then may be you should go for setting a more
granular statistics collection for your specific column-

alter table <table_name> alter column <column_Name> set statistics 1000;
analyze <table_name>;

​

Best Regards,

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