On 12/07/2016 09:58 AM, John R Pierce wrote:
On 12/7/2016 8:47 AM, Rob Sargent wrote:
Please tell me that in this case, updating 2 (big)integer columns
does not generate dead tuples (i.e. does not involve a insert/delete
pair).
if the fields being updated aren't indexed, and there's free tuple
space that has already been vacuumed in the same block, then the
update is done via "HOT" (or is it HEAT?) within the same block... but
with 1000s of updates per second to the same 500 rows ? odds of
autovacuum keeping up are sketchy.. otherwise, all updates are
insert/delete operations due to the requirements of MVCC
How does your reply change, if at all, if:
- Fields not index
- 5000 hot records per 100K records (millions of records total)
- A dozen machines writing 1 update per 10 seconds (one machine
writing every 2 mins)
- - each to a different "5000"
or (two modes of operation)
- - each to same "5000"
My guess this would be slow enough even in the second mode? Or at this
rate and style should I care?
Sorry for taking this off from OP's point
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