Обсуждение: fill factor guestimate

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fill factor guestimate

От
Dave Thompson
Дата:
Hi,

I have a table that will be updated frequently. Each row will be
updated at least once during it's lifetime, and most rows will be
updated ~10 times in their first 2 weeks of existence, and then
relatively rarely after that. The rows are being updated by a prepared
statement that gets executed with ~100 - ~600 different parameter
sets, each one updating a single row. What should my initial
best-guess fill-factor for the table be? Most of the updates don't
touch an indexed column, so I'm hoping to take advantage of the HOT
update feature. Will EXPLAIN tell me if an UPDATE uses HOT?

thanks
-Dave

Re: fill factor guestimate

От
Scott Marlowe
Дата:
On Sat, Jun 18, 2011 at 6:12 PM, Dave Thompson <dthomp325@gmail.com> wrote:
> Hi,
>
> I have a table that will be updated frequently. Each row will be
> updated at least once during it's lifetime, and most rows will be
> updated ~10 times in their first 2 weeks of existence, and then
> relatively rarely after that. The rows are being updated by a prepared
> statement that gets executed with ~100 - ~600 different parameter
> sets, each one updating a single row. What should my initial
> best-guess fill-factor for the table be? Most of the updates don't
> touch an indexed column, so I'm hoping to take advantage of the HOT
> update feature. Will EXPLAIN tell me if an UPDATE uses HOT?

No but you can monitor pg_stat_user_tables to see how many updates
were HOT updates.