Re: a JOIN to a VIEW seems slow

Frank Millman wrote:
>
> On Thu, Sep 21, 2017 at 3:54 PM, Merlin Moncure wrote:

> > Something is not adding up here. Can you EXPLAIN ANALYZE the 26 minute
> > query?

> Here it is -
>
> https://explain.depesz.com/s/cwm
>

There is one thing I have not mentioned. I am pretty sure it has no effect on the outcome, but just in case, here it is.

The underlying physical tables, ‘ar_tran_inv’, ‘ar_tran_crn’, and ‘ar_tran_rec’, have this index declared -

CREATE UNIQUE INDEX _ar_tran_inv ON ar_tran_inv (tran_number) WHERE deleted_id = 0;

and similar for the other two tables.

I have not included the column ‘deleted_id’ in the VIEW ‘ar_trans’, so I cannot add ‘WHERE deleted_id = 0’ to any queries.

This could mean a slow result if sorting by ‘tran_number’ or joining on ‘tran_number’.

However, as this particular query joins on ‘tran_type’ (a literal string) and ‘tran_row_id’ (the primary key to the underlying table), I don’t think it causes a problem.

[UPDATE] I actually tried adding ‘deleted_id’ to the VIEW, and including it in the WHERE clause, but the timings did not improve.

Frank