Re: "get snapshot for locks" memory structure
On Wed, 23 Jul 2003 09:09:37 -0700, Bruce Pullen wrote:
> DB2 v188.8.131.52 n AIX 184.108.40.206
> I'd like to know
> 1) What memory structure DB2 requires for it's "get snapshot" commands
> (is it UTIL_HEAP_SZ?)
No, UTIL_HEAP_SZ is for things like backups, reorgs and other utilities.
The area used to store monitoring information is the DBM CFG parameter
> 2) Whether, when a lock escalates (i.e. when an application exceeds
> the locklist divided by maxlocks value), any db configuration
> parameter limits the amount of memory it swallows up. Or does the
> application grab all the machine memory that's available?
Not sure what your question is here. When a lock is escalated (e.g. from
page to table) the purpose is to REDUCE memory usage. The many page locks
in memory would be replaced by one table lock, thus freeing up a lot of the memory
used in the locklist.
> 3) Whether applications in Lock-Wait acquire any (lock) memory.
Since they've not been able to acquire a lock yet I'd guess not : but I'd
guess DB2 stores a list of things waiting on a resource in some sort of
HINT : the default value for LOCKTIMEOUT (-1) is bad in almost all cases.
Suggest you set this to something else (10 seconds might be a good