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PL/PgSQL for counting all rows in all tables.

From: David Fetter <david(at)fetter(dot)org>
To: PG Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: PL/PgSQL for counting all rows in all tables.
Date: 2004-09-29 00:00:49
Message-ID: 20040929000049.GA29701@fetter.org (view raw or flat)
Thread:
Lists: pgsql-hackers
Folks,

I've noticed that when coming into an organization, I need to do some
counting on what's in all the tables in a db.  This shortens that
process considerably, with the usual caveat that count(*) is a heavy
operation.

By the way, the 3 lines following "godawful hack" point to something
PL/PgSQL ought (imho) to be able to do, namely something like

EXECUTE INTO [ record | rowtype | type ] [sql TEXT string returning a single row];

Here 'tis: version 0.01...

CREATE TYPE table_count AS (table_name TEXT, num_rows INTEGER);

CREATE OR REPLACE FUNCTION count_em_all () RETURNS SETOF table_count
AS '
DECLARE
    the_count RECORD;
    t_name RECORD;
    r table_count%ROWTYPE;
BEGIN
    FOR t_name IN
        SELECT c.relname
        FROM
            pg_catalog.pg_class c
                LEFT JOIN
            pg_namespace n
                ON
            n.oid = c.relnamespace
        WHERE
            c.relkind = ''r''
                AND
            n.nspname = ''public''
        ORDER BY 1
    LOOP
        -- The next 3 lines are a godawful hack. :P
        FOR the_count IN EXECUTE ''SELECT COUNT(*) AS "count" FROM '' || t_name.relname
        LOOP
        END LOOP; 
        r.table_name := t_name.relname;
        r.num_rows := the_count.count;
        RETURN NEXT r;
    END LOOP;
    RETURN;
END;
' LANGUAGE plpgsql;

COMMENT ON FUNCTION count_em_all () IS 'Spits out all tables in the public schema and the exact row counts for each.';

-- 
David Fetter david(at)fetter(dot)org http://fetter.org/
phone: +1 510 893 6100   mobile: +1 415 235 3778

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Next:From: Greg Sabino MullaneDate: 2004-09-29 01:38:15
Subject: Re: PL/PgSQL for counting all rows in all tables.
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Subject: regression failure on Solaris contrib/cube

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