lock before older waiters, and having readlock people not share
locks if a writer is waiting for a lock, and waiting writers not
getting priority over waiting readers.
The following patches add to the backend a new debugging flag -K which prints
a debug trace of all locking operations on user relations (those with oid
greater than 20000). The code is compiled only if LOCK_MGR_DEBUG is defined,
so the patch should be harmless if not explicitly enabled.
I'm using the code to trace deadlock conditions caused by application queries
using the command "$POSTMASTER -D $PGDATA -o '-d 1 -K 1'.
The patches are for version 6.0 dated 970126.
Originally, I thought the problem was caused by a function that gets
called as a normal function where we want to return a value, and as a
signal handler where we need to have it accept a parameter (the signal
number) and it returns nothing, I was going to case the function name in
the signal call as (void (*)(int)).
Looking at all the source, it turns out this function only gets used as
a signal handler, so I set an int parameter and return void.
I have removed the Linux defines because they are not needed. BSD let
this sloppiness slide. Linux gave a compile error.
Submitted by: Bruce Momjian <maillist@candle.pha.pa.us>
In postgres95/src/backend/nodes/readfuncs, lines 1188 and 1189,
local_node->relname is taken to point to a NameType, while its
defined as a pointer to char. Both the casting to Name and the
call of namestrcpy should, IMHO, be changed appropriately (first
patch).
As far as I could see from the Linux signal header file,
a signal handler is declared as
typedef void (*__sighandler_t)(int);
Few changes to postgres95/src/backend/storage/lmgr/proc.c seem
appropriate to comply with this.
Finally, postgres95/src/bin/pg_version/pg_version.c defines
a function GetDataHome (by default, returning an integer)
and returns NULL in the function, which isn't an integer...
Submitted by: ernst.molitor@uni-bonn.de
Bruce Momjian
Marc G. Fournier
Bryan Henderson
Vadim B. Mikheev