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Tom Lane f32678c016 Reduce delay for last logicalrep feedback message when master goes idle.
The regression tests contain numerous cases where we do some activity on a
master server and then wait till the slave has ack'd flushing its copy of
that transaction.  Because WAL flush on the slave is asynchronous to the
logicalrep worker process, the worker cannot send such a feedback message
during the LogicalRepApplyLoop iteration where it processes the last data
from the master.  In the previous coding, the feedback message would come
out only when the loop's WaitLatchOrSocket call returned WL_TIMEOUT.  That
requires one full second of delay (NAPTIME_PER_CYCLE); and to add insult
to injury, it could take more than that if the WaitLatchOrSocket was
interrupted a few times by latch-setting events.

In reality we can expect the slave's walwriter process to have flushed the
WAL data after, more or less, WalWriterDelay (typically 200ms).  Hence,
if there are unacked transactions pending, make the wait delay only that
long rather than the full NAPTIME_PER_CYCLE.  Also, move one of the
send_feedback() calls into the loop main line, so that we'll check for the
need to send feedback even if we were woken by a latch event and not either
socket data or timeout.

It's not clear how much this matters for production purposes, but
it's definitely helpful for testing.

Discussion: https://postgr.es/m/30864.1498861103@sss.pgh.pa.us
2017-07-01 12:15:51 -04:00
config Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
contrib Fix typo in comment 2017-06-30 14:51:15 -04:00
doc Fix transition tables for partition/inheritance. 2017-06-28 18:55:03 +01:00
src Reduce delay for last logicalrep feedback message when master goes idle. 2017-07-01 12:15:51 -04:00
.dir-locals.el emacs: Set indent-tabs-mode in perl-mode 2015-04-12 23:53:23 -04:00
.gitattributes Remove contrib/tsearch2. 2017-02-13 11:06:11 -05:00
.gitignore Allow .so minor version numbers above 9 in .gitignore. 2016-08-15 17:35:35 -04:00
aclocal.m4 Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
configure Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
configure.in Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
COPYRIGHT Update copyright for 2017 2017-01-03 12:37:53 -05:00
GNUmakefile.in Have "make coverage" recurse into contrib as well 2016-09-05 18:44:36 -03:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Allow make check in PL directories 2011-02-15 06:52:12 +02:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00

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
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.