Re: Pluggable Storage - Andres's take
| От | Ashwin Agrawal |
|---|---|
| Тема | Re: Pluggable Storage - Andres's take |
| Дата | |
| Msg-id | CALfoeiuuWUt-xPnekcVdhp-a-CRDGyCYV-Jcg=W_xuZDd1xopw@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Pluggable Storage - Andres's take (Andres Freund <andres@anarazel.de>) |
| Ответы |
Re: Pluggable Storage - Andres's take
|
| Список | pgsql-hackers |
On Wed, May 15, 2019 at 11:54 AM Andres Freund <andres@anarazel.de> wrote:
Attached is a prototype of a variation of this. I added a
table_tuple_tid_valid(TableScanDesc sscan, ItemPointer tid)
callback / wrapper. Currently it just takes a "plain" scan, but we could
add a separate table_beginscan variant too.
For heap that just means we can just use HeapScanDesc's rs_nblock to
filter out invalid tids, and we only need to call
RelationGetNumberOfBlocks() once, rather than every
table_tuple_tid_valid(0 / table_get_latest_tid() call. Which is a good
improvement for nodeTidscan's table_get_latest_tid() call (for WHERE
CURRENT OF) - which previously computed the relation size once per
tuple.
Question on the patch, if not too late
Why call table_beginscan() in TidNext() and not in ExecInitTidScan() ? Seems cleaner to have it in ExecInitTidScan().
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