Postgres index usage

["Dirschel, Steve" <steve.dirschel@xxxxxxxxxxxxxxxxxx>]

I’ve found multiple postings out there saying you can query pg_stat_all_indexes and look at idx_scan to know if an index has been used by queries.  I want to be 100% sure I can rely on that table/column to know if an index has never been used.

 

I queried that table for a specific index and idx_scan is 0.  I queried pg_statio_all_indexes and can see idx_blks_read and idx_blks_hit have numbers in there.  If the index is not being used then what it causing idx_blks_read and idx_blks_hit to increase over time?  I’m wondering if those increase due to DML on the table.  Could anyone please confirm I can rely on pg_stat_all_index.idx_scan to know if queries are using an index and the increases over time in idx_blks_read and idx_blks_hit in pg_statio_all_indexes would be from DML (or possibly vacuum or other things)?

 

Thanks in advance.

This e-mail is for the sole use of the intended recipient and contains information that may be privileged and/or confidential. If you are not an intended recipient, please notify the sender by return e-mail and delete this e-mail and any attachments. Certain required legal entity disclosures can be accessed on our website: https://www.thomsonreuters.com/en/resources/disclosures.html