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pgpool-II load testingMuhammad Usama

May 7, 2014

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Goals and objectives

Stress testing

Load balancing / Statement Routing testing

Performance testing compared with PG running

on single machine

Cluster stability testing

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Hardware/Software configuration

Large amazon instances (15GB Ram with 4 2.5GHz intel Xeon)

PostgreSQL 9.3.2 pgpool-II version 3.3.3 Pgbench (benchmarking tool) 75% read and 25% write load (workload)

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Pgpool Cluster setup

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pgbench script (read intensive)

\set nbranches :scale\set ntellers 10 * :scale\set naccounts 100000 * :scale\setrandom aid 1 :naccounts\setrandom bid 1 :nbranches\setrandom tid 1 :ntellers\setrandom delta -5000 5000

BEGIN;UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;SELECT abalance FROM pgbench_accounts WHERE aid = :aid;UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);END;

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pgbench script cont…

\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;\setrandom aid 1 :naccountsSELECT abalance FROM pgbench_accounts WHERE aid = :aid;

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Test methodology

Automated test script

Performs fresh initdb for every test & executes each test 3 times

20 min run for each test

Test with 300, 1000 and 2000 scale factors

Median value of tps

Ensures repeatable results

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1000 Clients with 1000 and 2000 SF

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300 Clients with 300,1000,2000 SF

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100 Clients with 100,300,1000,2000 SF

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Horizontal read scalability. Addition of read replicas

increase performance for large size databases.

Better performance when database size increases then

memory. No performance gain for smaller databases which

fits in memory

Writes go to primary server and reads are load balanced

across the replicas.

Performance is not so good with prepared protocol. Doesn't crash but gives negligible performance gain.