Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM) - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)
Date
Msg-id 20170314191936.iypnhihuaa6btdm3@alvherre.pgsql
Whole thread Raw
In response to Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Responses Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)  (Pavan Deolasee <pavan.deolasee@gmail.com>)
Re: [HACKERS] Patch: Write Amplification Reduction Method (WARM)  (Peter Geoghegan <pg@bowt.ie>)
List pgsql-hackers
Pavan Deolasee wrote:

> BTW I wanted to share some more numbers from a recent performance test. I
> thought it's important because the latest patch has fully functional chain
> conversion code as well as all WAL-logging related pieces are in place
> too. I ran these tests on a box borrowed from Tomas (thanks!).  This has
> 64GB RAM and 350GB SSD with 1GB on-board RAM. I used the same test setup
> that I used for the first test results reported on this thread i.e. a
> modified pgbench_accounts table with additional columns and additional
> indexes (one index on abalance so that every UPDATE is a potential WARM
> update).
> 
> In a test where table + indexes exceeds RAM, running for 8hrs and
> auto-vacuum parameters set such that we get 2-3 autovacuums on the table
> during the test, we see WARM delivering more than 100% TPS as compared to
> master. In this graph, I've plotted a moving average of TPS and the spikes
> that we see coincides with the checkpoints (checkpoint_timeout is set to
> 20mins and max_wal_size large enough to avoid any xlog-based checkpoints).
> The spikes are more prominent on WARM but I guess that's purely because it
> delivers much higher TPS. I haven't shown here but I see WARM updates close
> to 65-70% of the total updates. Also there is significant reduction in WAL
> generated per txn.

Impressive results.  Labels on axes would improve readability of the chart :-)

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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