Re: Extremely slow intarray index creation and inserts.

From: Tom Lane
Subject: Re: Extremely slow intarray index creation and inserts.
Date: ,
Msg-id: 1804.1237346699@sss.pgh.pa.us
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In response to: Re: Extremely slow intarray index creation and inserts.  (Ron Mayer)
Responses: Re: Extremely slow intarray index creation and inserts.  (Ron Mayer)
List: pgsql-performance


Ron Mayer <> writes:
> vm=# create index "gist70000" on tmp_intarray_test using GIST (my_int_array gist__int_ops);
> CREATE INDEX
> Time: 2069836.856 ms

> Is that expected, or does it sound like a bug to take over
> half an hour to index 70000 rows of mostly 5 and 6-element
> integer arrays?

I poked at this example with oprofile.  It's entirely CPU-bound AFAICT,
and the CPU utilization is approximately

    55%    g_int_compress
    35%    memmove/memcpy (difficult to distinguish these)
     1%    pg_qsort
    <1%    anything else

Probably need to look at reducing the number of calls to g_int_compress
... it must be getting called a whole lot more than once per new index
entry, and I wonder why that should need to be.

            regards, tom lane


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