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Heikki Linnakangas c8b2499111 Simplify calculation of Poisson distributed delays in pgbench --rate mode.
The previous coding first generated a uniform random value between 0.0 and
1.0, then converted that to an integer between 1 and 10000, and divided that
again by 10000. Those conversions are unnecessary; we can use the double
value that pg_erand48() returns directly. While we're at it, put the logic
into a helper function, getPoissonRand().

The largest delay generated by the old coding was about 9.2 times the
average, because of the way the uniformly distributed value used for the
calculation was truncated to 1/10000 granularity. The new coding doesn't
have such clamping. With my laptop's DBL_MIN value, the maximum delay with
the new coding is about 700x the average. That seems acceptable - any
reasonable pgbench session should last long enough to average that out.

Backpatch to 9.4.
2014-09-11 13:12:43 +03:00
config
contrib Simplify calculation of Poisson distributed delays in pgbench --rate mode. 2014-09-11 13:12:43 +03:00
doc Change the way latency is calculated with pgbench --rate option. 2014-09-11 12:57:21 +03:00
src Handle old versions of Test::More 2014-09-10 20:52:50 -04:00
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.gitattributes gitattributes: Ignore time zone data files for whitespace checks 2014-07-22 00:12:28 -04:00
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aclocal.m4
configure Diagnose incompatible OpenLDAP versions during build and test. 2014-07-22 11:01:35 -04:00
configure.in Diagnose incompatible OpenLDAP versions during build and test. 2014-07-22 11:01:35 -04:00
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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:

	http://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
http://www.postgresql.org/download/.  For more information look at our
web site located at http://www.postgresql.org/.