On 02.11.2015 06:17, Craig Ringer wrote:
On 31 October 2015 at 17:22, konstantin knizhnik
<k.knizh...@postgrespro.ru> wrote:
Waiting for your feedback
For anyone wondering about performance impact, there are some graphs
on page 23 of the PDF presentation. I didn't see anything else, and
the graphs don't seem to cover comparison of Pg with the XTM
transaction manager hooks and no DTM enabled vs Pg without the hooks,
i.e. the hook overhead its self.
Have you done much work on that? Personally I wouldn't expect to see
any meaningful overhead, but I'd really like to have numbers behind
that.
Overhead of indirect call is negligible - see for example
https://gist.github.com/rianhunter/0be8dc116b120ad5fdd4
But we have certainly performed comparison of PostgreSQL with/without
XTM patch.
Pgbench results are almost the same - within the measurement error:
With XTM:
transaction type: TPC-B (sort of)
scaling factor: 70
query mode: simple
number of clients: 144
number of threads: 24
duration: 600 s
number of transactions actually processed: 12275179
latency average: 7.037 ms
latency stddev: 46.787 ms
tps = 20456.945469 (including connections establishing)
tps = 20457.164023 (excluding connections establishing)
Without XTM:
transaction type: TPC-B (sort of)
scaling factor: 70
query mode: simple
number of clients: 144
number of threads: 24
duration: 600 s
number of transactions actually processed: 12086367
latency average: 7.156 ms
latency stddev: 48.431 ms
tps = 20114.491785 (including connections establishing)
tps = 20116.074391 (excluding connections establishing)
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