From: Michael Widenius
Date: June 5 2009 7:42pm
Subject: Re: A call to rnd_pos() without a call to position()?
List-Archive: http://lists.mysql.com/internals/36849
Message-Id: <18985.30012.477318.941902@narttu.askmonty.org>
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Hi!

>>>>> "Vyacheslav" == Vyacheslav Akhmechet <coffeemug@stripped> writes:

Vyacheslav> After a bit more digging I discovered that this happens because I
Vyacheslav> didn't return HA_REC_NOT_IN_SEQ as one of the table flags. Once I
Vyacheslav> return the flag, position() gets called prior to rnd_pos(). I suppose
Vyacheslav> without the flag, the server expects rnd_pos() to figure out the
Vyacheslav> position of the row without storing it first (since the rows would be
Vyacheslav> stored in sequence, so it would be a question of a simple
Vyacheslav> multiplication).

Correct.

Regards,
Monty