pg_mem_counters

This is a small extension for keeping total and rpm counters in shared memory of PostgreSQL server.

Features

• Saves total hit for named counters in shared memory
• Saves RPM (requests per minute) for named counters in shared memory

PostgreSQL PostgreSQL 10, 11 are supported.

Functions

FUNCTION inc_mem_counter(counter text, increment int8 default 0) RETURNS int8;
FUNCTION get_mem_counter_rpm(counter text) RETURNS int8;
FUNCTION mem_counters() RETURNS TABLE (name text, total int8, rpm int8);

Usage

Add counter 'counter1' incremented with 1 hit and get total hits:

postgres=# select inc_mem_counter('counter1', 1);

Only get total hits of counter 'counter1':

postgres=# select inc_mem_counter('counter1');    

Get counter 'counter1' RPM:

postgres=# select get_mem_counter_rpm('counter1');

Get table of all counters with total hits and RPM:

postgres=# select * from mem_counters();

Configuration

Edit postgresql.conf file, add extension to shared_preload_libraries:

shared_preload_libraries = 'pg_mem_counters' # (change requires restart)

Compilation

You need a development environment for PostgreSQL extensions:

export PATH="$PATH:/usr/pgsql-10/bin"
make USE_PGXS=1 clean    
make USE_PGXS=1 all
make USE_PGXS=1 install

postgres=# create extension pg_mem_counters;

result:

[topper@osboxes pg_mem_counters]# make USE_PGXS=1 clean
rm -f pg_mem_counters.so pg_mem_counters.o
rm -f pg_mem_counters.o
rm -rf results/ regression.diffs regression.out tmp_check/ tmp_check_iso/ log/ output_iso/
[topper@osboxes pg_mem_counters]# make USE_PGXS=1 all
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -fPIC -I. -I./ -I/usr/pgsql-10/include/server -I/usr/pgsql-10/include/internal  -D_GNU_SOURCE -I/usr/include/libxml2  -I/usr/include  -c -o pg_mem_counters.o pg_mem_counters.c
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -fPIC -L/usr/pgsql-10/lib -Wl,--as-needed  -L/usr/lib64 -Wl,--as-needed -Wl,-rpath,'/usr/pgsql-10/lib',--enable-new-dtags  -shared -o pg_mem_counters.so pg_mem_counters.o
[topper@osboxes pg_mem_counters]# make USE_PGXS=1 install
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -fPIC -I. -I./ -I/usr/pgsql-10/include/server -I/usr/pgsql-10/include/internal  -D_GNU_SOURCE -I/usr/include/libxml2  -I/usr/include  -c -o pg_mem_counters.o pg_mem_counters.c
gcc -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fexcess-precision=standard -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -fPIC -L/usr/pgsql-10/lib -Wl,--as-needed  -L/usr/lib64 -Wl,--as-needed -Wl,-rpath,'/usr/pgsql-10/lib',--enable-new-dtags  -shared -o pg_mem_counters.so pg_mem_counters.o
/usr/bin/mkdir -p '/usr/pgsql-10/share/extension'
/usr/bin/mkdir -p '/usr/pgsql-10/share/extension'
/usr/bin/mkdir -p '/usr/pgsql-10/lib'
/usr/bin/install -c -m 644 .//pg_mem_counters.control '/usr/pgsql-10/share/extension/'
/usr/bin/install -c -m 644 .//pg_mem_counters--1.0.sql  '/usr/pgsql-10/share/extension/'
/usr/bin/install -c -m 755  pg_mem_counters.so '/usr/pgsql-10/lib/'

Licence

Copyright (c) Victor Kosonogov ([email protected])

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.