Re: bloat indexes - opinion

2017-02-23 11:46 GMT+13:00 Jeff Janes <jeff(dot)janes(at)gmail(dot)com>:

> On Tue, Feb 21, 2017 at 1:44 PM, Patrick B <patrickbakerbr(at)gmail(dot)com>
> wrote:
>
>> Hi guys,
>>
>> I've got a lot of bloat indexes on my 4TB database.
>>
>> Let's take this example:
>>
>> Table: seg
>> Index: ix_filter_by_tree
>> Times_used: 1018082183
>> Table_size: 18 GB -- wrong. The table is mostly on pg_toast table. Its
>> real size is 2TB
>> Index_size: 17 GB
>> Num_writes 16245023
>> Index definition: CREATE INDEX ix_filter_by_tree ON seg USING btree
>> (full_path varchar_pattern_ops) WHERE (full_path IS NOT NULL)
>>
>>
> What is this from? If you think the table size reported should include
> toast, then change it to do that, or request the author of whatever-this-is
> to make that change.
>
> What indication is there that the index is bloated? If the
> meat-and-potatoes of a table is held in toast, then wouldn't you expect the
> size of the table and the size of the index to be about the same?
>
> Cheers,
>
> Jeff
>

I am running queries to see bloat indexes [1]. Also i understand an index
can't have same size as table.
If you have any other table that can prove the index is indeed bloat,
please let me know and i will be happy to post results here.

[1] https://wiki.postgresql.org/wiki/Index_Maintenance

Patrick