Thank you David, I copied the detailed activity from the report as below. As it
shows, it has prepare and bind queries. One of the item has Bind/Prepare
pretty high as 439.50. so that looks like a good value?
Another question is if bind only happens in a prepared statement?
Day Hour Prepare Bind Bind/Prepare Percentage of prepare
Jun 03 00 205 209 1.02 1.27%
01 19 19 1.00 0.17%
02 0 0 0.00 0.00%
03 0 0 0.00 0.00%
04 6 6 1.00 0.00%
05 2 879 439.50 0.02%
06 839 1,323 1.58 7.01%
07 0 0 0.00 0.00%
Thanks,
Suya
-----Original Message-----
From: pgsql-performance-ow...@postgresql.org
[mailto:pgsql-performance-ow...@postgresql.org] On Behalf Of David G Johnston
Sent: Thursday, June 05, 2014 11:58 AM
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] parse/bind/execute
Huang, Suya wrote
> Hello,
>
> I am using Pgbadger to analyze the postgresql database log recently
> and noticed a section "Prepared queries ratio". For my report, it has:
>
> 1.03 as Ratio of bind vs prepare
> 0.12% Ratio between prepared and "usual" statements
>
> I'm trying to understand what the above metrics mean and if it's a
> problem. I found people can clearly clarify the parse/bind/execute
> time of a query. To my limited knowledge of Postgres, using explain
> analyze, I can only get the total execution time.
>
> Can someone shed me some light on this subject? How to interpret the
> ratios?
>
> Thanks,
> Suya
Both are related to using prepared statements (usually with parameters).
Each bind is a use of an already prepared query with parameters filled in.
The prepare is the initial preparation of the query. A ratio of 1 means that
each time you prepare a query you use it once then throw it away.
Likewise a value of 2 would mean you are executing each prepared statement
twice.
"Usual" statements are those that are not prepared. The ratio is simply the
counts of each as seen by the database - I do not know specifics as to what
exactly is counted (ddl?).
That low a ratio means that almost all statements you send to the database are
non-prepared. In those relatively few cases where you do prepare first you
almost always immediately execute a single set of inputs then discard the
prepared statement.
I do not know enough about the underlying data to draw a conclusion but
typically the higher the bind/prepare ratio the more efficient your use of
database resources. Same goes for the prepare ratio. The clients you use and
the general usage of the database heavily influence what would be considered
reasonable ratios.
David J.
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