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Thread: Ingres statdump equivalent for postgresql

Ingres statdump equivalent for postgresql

From
badair@epc-instore.com
Date:
Hello all,
I'm looking for a tool that will enable me to dump the data frequency histograms
for a postgresql table. This assumes of course that postgresql supports compilation and use of these sort of
statistics.I've had a look through the manuals but nothing springs to the eye. 
TIA
Bill

Re: Ingres statdump equivalent for postgresql

From
"Kevin Grittner"
Date:
<badair@epc-instore.com> wrote:

> I'm looking for a tool that will enable me to dump the data
> frequency histograms for a postgresql table. This assumes of
> course that postgresql supports compilation and use of these sort
> of statistics. I've had a look through the manuals but nothing
> springs to the eye.

Did you look at the system catalogs in the documentation?  It sounds
like you want some of the information from pg_statistic in pretty
form?

http://www.postgresql.org/docs/current/interactive/catalog-pg-statistic.html

You might also want to read about the ANALYZE command.

-Kevin

Re: Ingres statdump equivalent for postgresql

From
Tom Lane
Date:
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Did you look at the system catalogs in the documentation?  It sounds
> like you want some of the information from pg_statistic in pretty
> form?

... like the pg_stats view?

            regards, tom lane

Re: Ingres statdump equivalent for postgresql

From
Greg Smith
Date:
badair@epc-instore.com wrote:
> I'm looking for a tool that will enable me to dump the data frequency histograms
> for a postgresql table.

#!/bin/bash
DB="$1"
TABLE="$2"
psql -d $DB -x -c "SELECT
tablename,attname,null_frac,avg_width,n_distinct,correlation,most_common_vals,most_common_freqs,histogram_bounds
FROM pg_stats where tablename='$TABLE'"

Run that, pass it database then table name, and you'll get the data for
each column in that table.  That should get you started; refer to
http://www.postgresql.org/docs/current/interactive/catalog-pg-statistic.html
and to
http://www.postgresql.org/docs/current/interactive/planner-stats-details.html
for more details.

--
Greg Smith, 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services and Support  www.2ndQuadrant.us
Author, "PostgreSQL 9.0 High Performance"    Pre-ordering at:
https://www.packtpub.com/postgresql-9-0-high-performance/book