Hello Kevin
> If you use EXPLAIN with both statements...
Yes, the plans are indeed very different.
Here is the statement, set to update up to 100,000 records, which took
about 5 seconds to complete:
UPDATE
table_A
SET
field_1 = table_B.field_1
, field_2 = table_B.field_2
FROM
table_B
Harry Mantheakis wrote:
The mystery remains, for me: why updating 100,000 records could
complete in as quickly as 5 seconds, whereas an attempt to update a
million records was still running after 25 minutes before we killed it?
The way you were doing this originally, it was joining every recor
On Mon, Jun 27, 2011 at 5:37 PM, wrote:
>> The mystery remains, for me: why updating 100,000 records could complete
>> in as quickly as 5 seconds, whereas an attempt to update a million
>> records was still running after 25 minutes before we killed it?
>
> Hi, there's a lot of possible causes. Us
> The mystery remains, for me: why updating 100,000 records could complete
> in as quickly as 5 seconds, whereas an attempt to update a million
> records was still running after 25 minutes before we killed it?
Hi, there's a lot of possible causes. Usually this is caused by a plan
change - imagine
Harry Mantheakis wrote:
> I am glad to report that the 'salami-slice' approach worked nicely
> - all done in about 2.5 hours.
Glad to hear it!
> The mystery remains, for me: why updating 100,000 records could
> complete in as quickly as 5 seconds, whereas an attempt to update
> a million rec
I am glad to report that the 'salami-slice' approach worked nicely - all
done in about 2.5 hours.
Instead of using an all-in-one-go statement, we executed 800 statements,
each updating 100,000 records. On average it tool about 10-seconds for
each statement to return.
This is "thinking out of
