Thread

1. some problems with new locking code

   Vadim Mikheev <vadim@sable.krasnoyarsk.su> — 1998-02-24T14:56:12Z

   I created simple table (just single int4 attr) with index on it
   and tried to reproduce reported problems with BTP_CHAIN flag
   (without success, unfortunately ?) by inserting data by 3-4 psql-s 
   simultaneously. No problems with 2 clients. But when 3rd psql
   starts one of psql-s becomes blocked for long time (a minutes). 
   After some time blocked process may continue insertion but 
   another process is sleeping instead of wake-uped proc. The same
   with 4 psql-s: one of process is always sleeping!
   
   It's very easy to reproduce - just create a file with >~ 100
   INSERTs...
   
   I also run 2 insertion procs + 2 selecting procs - result is
   the same, one is always sleeping.
   
   Vadim
   P.S. Nevertheless, I really like new deadlock recognition code,
   thanks!
   
   

2. Re: [HACKERS] some problems with new locking code

   Bruce Momjian <maillist@candle.pha.pa.us> — 1998-02-24T19:56:58Z

   > 
   > I created simple table (just single int4 attr) with index on it
   > and tried to reproduce reported problems with BTP_CHAIN flag
   > (without success, unfortunately ?) by inserting data by 3-4 psql-s 
   > simultaneously. No problems with 2 clients. But when 3rd psql
   > starts one of psql-s becomes blocked for long time (a minutes). 
   > After some time blocked process may continue insertion but 
   > another process is sleeping instead of wake-uped proc. The same
   > with 4 psql-s: one of process is always sleeping!
   
   Thanks for finding this, Vadim.  I had meant to re-run my locking tests
   on the new code before the 6.3 final, but had not done it yet.  I ran
   them now, and they didn't work as they should.  It is fixed now.
   
   The problem was that I was incrementing a counter in a while conditional
   test, even though I was not executing the loop, and the counter was used
   in the next loop.
   
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