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From Chip Mitchell <chipmitch...@outlook.com>
Subject SYSCOLUMNS Locking Under High Load
Date Wed, 14 Jan 2015 15:00:04 GMT
Hey all - I was wondering if anyone has come accross this situation before. We have a relatively
simple table (below). And it seems that during high insert loads, we see long running transactions
and locking. But what I was surprised to see was that the lock was coming out of the SYSCOLUMNS
table. The only thing I was suspect of was whether or not that it's the IDENTITY on the first
field that might be contributing here.
Some additional info follows, but if there is a specific piece that would also help, let me
know and I can reply with it.
Derby: 10.8.2.2

Table Definition:CREATE TABLE "TEST"."INFO" (   "SEQUENCE" INTEGER NOT NULL GENERATED ALWAYS
AS IDENTITY (START WITH 1, INCREMENT BY 1),   "ID" CHARACTER(18) NOT NULL,   "TYPE" INTEGER
NOT NULL,   "DESC" CHARACTER(18) NOT NULL,   "DESC_TYPE" INTEGER NOT NULL,   "CREATED" TIMESTAMP
DEFAULT CURRENT_TIMESTAMP );

derby.locks.waitTimeout - 600derby.locks.escalationThreshold - 70000000


XID       |TYPE         |MODE|LOCKCOUNT|LOCKNAME                                         
                              |STATE|TABLETYPE / LOCKOBJ                   |INDEXNAME / CONTAINER_ID
/ (MODE for LATCH only)  |TABLENAME / CONGLOM_ID                |----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------***
The following row is the victim ***1995383222|ROW          |S   |0        |(44,53)       
                                                                 |WAIT |S                
                    |NULL                                              |SYSCOLUMNS       
                    |*** The above row is the victim ***1995383233|ROW          |X   |2  
     |(44,53)                                                                         |GRANT|S
                                    |NULL                                              |SYSCOLUMNS
                           |1995383236|ROW          |S   |0        |(44,53)              
                                                          |WAIT |S                       
             |NULL                                              |SYSCOLUMNS              
             |1995383242|ROW          |X   |0        |(44,53)                            
                                            |WAIT |S                                     |NULL
                                             |SYSCOLUMNS                            |1995383254|ROW
         |X   |0        |(44,53)                                                         
               |WAIT |S                                     |NULL                        
                     |SYSCOLUMNS                            |1995383255|ROW          |X  
|0        |(44,53)                                                                       
 |WAIT |S                                     |NULL                                      
       |SYSCOLUMNS                            |1995383257|ROW          |X   |0        |(44,53)
                                                                        |WAIT |S         
                           |NULL                                              |SYSCOLUMNS
          

Any thoughts or insights are greatly appreciated.
Thank you all! 		 	   		  
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