Transaction costs?
Just wondering what the cost of begin/end transaction is.
This is for pg_dump which, when restoring BLOBs, inserts multiple rows into
a temporary xref table. The sequence of events is:
Conn1: Begin
Conn1: lo_create/lo_close/lo_write.../lo_close
Conn2: Insert into xref table (which does an implicit begin/end, I think).
Conn1: Commit;
Would I get substantially better performance by doing a begin/end every
10/100/1000 rows in each connection, or is the transaction overhead low? Or
is this something I just need to test?
[eg. in Dec/RDB TX begin/end is expensive, but writing more than 1000 rows
in a TX can also be costly, so a compromise is useful]
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and from pgp5.ai.mit.edu:11371 |/
Philip Warner <pjw@rhyme.com.au> writes:
This is for pg_dump which, when restoring BLOBs, inserts multiple rows into
a temporary xref table. The sequence of events is:
Conn1: Begin
Conn1: lo_create/lo_close/lo_write.../lo_close
Conn2: Insert into xref table (which does an implicit begin/end, I think).
Conn1: Commit;
Two connections? Why in the world are you doing it like that --- and
especially in that order? Seems like this is committing an xref change
before the LO itself is committed. Why?
regards, tom lane
At 11:33 2/11/00 -0500, Tom Lane wrote:
Conn1: Begin
Conn1: lo_create/lo_close/lo_write.../lo_close
Conn2: Insert into xref table (which does an implicit begin/end, I think).
Conn1: Commit;Two connections?
Otherwise a reconnect will lose the temp table contents.
----------------------------------------------------------------
Philip Warner | __---_____
Albatross Consulting Pty. Ltd. |----/ - \
(A.B.N. 75 008 659 498) | /(@) ______---_
Tel: (+61) 0500 83 82 81 | _________ \
Fax: (+61) 0500 83 82 82 | ___________ |
Http://www.rhyme.com.au | / \|
| --________--
PGP key available upon request, | /
and from pgp5.ai.mit.edu:11371 |/