Re: BUG #16540: Possible corrupted file?

Hi Tom

Many thanks for the feedback.

I did do an explain on both the 10second and the never ending.  The actual structure of the plan was identical - there
werea couple of very minor differences in costs and widths but we're talking cost of 200,000 vs 199,500 kind of
differences.

Thanks

Paul Hatcher
Senior Consultant
Sentinel Partners Limited
W: sentinelpartners.co.uk
M: 07788 673898
T: 0800 612 2116
 
 

On 14/07/2020, 15:01, "Tom Lane" <tgl@sss.pgh.pa.us> wrote:

    PG Bug reporting form <noreply@postgresql.org> writes:
    > We had a situation where a query that normally ran in 10 seconds instead
    > never completed.  No conflicts or locks could be seen.  All indexes were
    > valid and in place.  A full shutdown and restart of the server was done with
    > no effect.
    > To test we took a full backup of this system and restored to an identical
    > alternate system.  Having done this, the alternate system ran the query in
    > 10 seconds.
    > Final test was to backup and restore back into the production system -
    > having done this the query returned to running in 10 seconds.  Do you have
    > any idea what could have caused this?
    
    The most obvious theory is a change of query plan, perhaps due to having
    up-to-date ANALYZE statistics in one case and not the other.  I don't
    suppose you captured EXPLAIN output for the non-working state?
    
                regards, tom lane