From: Charles Jardine <cj10@cam.ac.uk>
Subject: Shared row locks?
Date: 1996/12/12
Message-ID: <32AFEAD8.3010@cam.ac.uk>#1/1
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The 7.2 Server concepts guide asserts that row locks are always
exclusive (top of page 10-11).

However, I have seen the lock monitor show a session waiting
of a lock of type TX and mode S, i.e. a *shared* row lock.

The session is question was blocked in foreign key processing
while deleting a master row. The only reference to the row was
from a detail row which had been inserted but not yet committed.
The master row delete was apparently waiting for a shared row
lock on the uncommitted detail record.

Does anyone know where I can find out more about shared row
locks? Is it possible to request one explicitly?

I am using server version 7.2.3.0.0 under Solaris 2.4.

Charles Jardine - University of Cambridge (UK) Computing Service