Re: Very slow updates when using IN syntax subselect

Peter Eisentraut wrote:
> Bryce Nesbitt wrote:
>   
>>> It seems pretty clear that you've never vacuumed nor analyzed these
>>> tables ... else the planner would have some clue about their sizes.
>>> Do that and then see what you get.
>>>       
>> They occur in fine time.  That's good, thanks.  But jeeze, can't
>> postgres figure this out for itself?
>>     
>
> I'm sure you wouldn't appreciate it if PostgreSQL did a full table scan 
> before each query to figure out the total size of the involved tables.
>   
Nope.

But let's say the query optimizer thought the table had one row.
The the query starts, and 111,000 rows later...

It seems that a mismatch between the static table size, and the actual
one counted as you go, would be a quick
check.  That could set a flag for later background processing....
                                                      -Bryce