Updates statistics for each column in the table. If your version is older
than 7.31UD2 or 9.30 [not certain for 9] I think you will find that the
table is read multiple times, once for each col in the table.

This would explain the astronomical increase in the runtime.

Mark

----- Original Message -----
From: "Thomas J. Girsch" <tgirsch@worldnet.att.net>
To: <informix-list@iiug.org>
Sent: Thursday, August 21, 2003 21:12
Subject: UPDATE STATISTICS


> Imagine a table tab1 with a bazillion rows and five columns. There is one
> index on the table, on column A.
>
> If I do:
>
> UPDATE STATISTICS LOW FOR TABLE tab1(col_a);
>
> ... it runs very quickly. But if I just do:
>
> UPDATE STATISTICS LOW FOR TABLE tab1;
>
> ... it takes hours, maybe days. So what exactly does the latter command
do,
> that the former command does NOT do?
>
>

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