Re: bloat indexes - opinion

[Patrick B <patrickbakerbr@xxxxxxxxx>]

2017-02-23 11:46 GMT+13:00 Jeff Janes <jeff.janes@xxxxxxxxx>:

On Tue, Feb 21, 2017 at 1:44 PM, Patrick B <patrickbakerbr@xxxxxxxxx> 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