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Tomas Vondra b676ac443b Optimize creation of slots for FDW bulk inserts
Commit b663a41363 introduced bulk inserts for FDW, but the handling of
tuple slots turned out to be problematic for two reasons. Firstly, the
slots were re-created for each individual batch. Secondly, all slots
referenced the same tuple descriptor - with reasonably small batches
this is not an issue, but with large batches this triggers O(N^2)
behavior in the resource owner code.

These two issues work against each other - to reduce the number of times
a slot has to be created/dropped, larger batches are needed. However,
the larger the batch, the more expensive the resource owner gets. For
practical batch sizes (100 - 1000) this would not be a big problem, as
the benefits (latency savings) greatly exceed the resource owner costs.
But for extremely large batches it might be much worse, possibly even
losing with non-batching mode.

Fixed by initializing tuple slots only once (and reusing them across
batches) and by using a new tuple descriptor copy for each slot.

Discussion: https://postgr.es/m/ebbbcc7d-4286-8c28-0272-61b4753af761%40enterprisedb.com
2021-06-11 20:23:33 +02:00
config Update config.guess and config.sub 2021-04-21 16:33:40 +02:00
contrib Adjust batch size in postgres_fdw to not use too many parameters 2021-06-08 20:28:31 +02:00
doc Rename PQtraceSetFlags() to PQsetTraceFlags(). 2021-06-10 21:56:13 -07:00
src Optimize creation of slots for FDW bulk inserts 2021-06-11 20:23:33 +02:00
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.gitattributes gitattributes: Add new entry to silence whitespace error 2021-06-05 07:57:31 +02:00
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aclocal.m4 Remove configure-time probe for DocBook DTD. 2020-11-30 15:24:13 -05:00
configure Stamp 14beta1. 2021-05-17 16:11:18 -04:00
configure.ac Stamp 14beta1. 2021-05-17 16:11:18 -04:00
COPYRIGHT Update copyright for 2021 2021-01-02 13:06:25 -05:00
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PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
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system.  Copyright and license information can be found in the
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