Lockstat Command Output – Locking System Statistics
The Locking System Statistics portion of the sample output is a listing of locking activity for the installation. All values are cumulative from the time ingstart was run for this iteration of the system.
The "Statistics by lock type" portion of the statistics output is described in
Lockstat Command Output – Statistics by Lock Type.
Here is sample output from the Statistics section:
========Mon Feb 12 13:34:06 2018 Locking System Statistics======
Create lock list 78317 Release lock list 78215
Request lock 2834 Re-request lock 1367807
Convert lock 39 Release lock 1560831
Escalate 0 Lock wait 1327
Convert wait 0 Convert Deadlock 0
Deadlock Wakeups 0 Max dlk queue len 0
Deadlock Search 0 Deadlock 0
Cancel 0 Convert Search 0
Allocate CB 2887 Deallocate CB 1884645
LLB Highwater 60 LKB Highwater 176
RSB Highwater 2059 CBT Highwater 0
Max Local dlk srch 0 Dlk locks examined 0
Max rsrc chain len 13 Max lock chain len 9
Max locks per txn 1679 Callback Wakeups 0
Callbacks Invoked 0 Callbacks Ignored 0
CB stash scavenge 0 Scavenge LLBs 0
Scavenge skipped 0
Fields are as follows:
Create lock list
Number of times a lock list was created for server, session, or transaction
Release lock list
Number of times a release of a lock list occurred for a server, session, or transaction
Request lock
Number of new lock requests that the locking system processed
Re-request lock
Number of times an implicit lock conversion request was issued on a resource that the lock list already had locked. Implicit lock conversion requests can occur when a request is made on a page for update that was previously requested for read.
Convert lock
Number of times an explicit lock conversion request is made to change a lock mode on a physical lock from one mode to another. These types of requests occur as a result of a physical lock being converted during an existing transaction to lower or higher modes.
Release lock
Number of times a specific logical lock is released, as opposed to a full, partial, or physical lock release.
Escalate
Number of times a partial release occurred to allow lock escalation from page to table level
Lock wait
Number of times a new lock request had to wait to be granted
Convert wait
Number of times an existing lock waited for conversion to a different lock mode
Convert deadlock
Number of times a request for conversion turned into a deadlock
Deadlock Wakeups
Number of times the interval-based deadlock detection thread was awakened
Max dlk queue len
Maximum number of waiting lock lists examined by the deadlock detection thread
Deadlock search
Number of times a deadlock search was initiated
Deadlock
Number of times that deadlock existed
Cancel
Number of times a lock request was canceled due to a time-out or interrupt
Convert search
Number of times a convert deadlock search was initiated. The searches are performed when converting a lock from one mode to another.
Allocate CB
Number of locking control block allocations. The use of the lock block (LKB) embedded inside a resource block (RSB) does not count as an allocation.
Deallocate CB
Number of locking control block deallocations. The use of the lock block (LKB) embedded inside a resource block (RSB) does not count as a deallocation.
LLB Highwater
Maximum number of lock lists allocated
LKB Highwater
Maximum number of floating lock blocks (LKB) ever in use. A floating LKB is one that can lock any resources. The resource block (RSB) contains one LKB embedded within it, but that LKB can only be used to lock that resource, not any other resource.
RSB Highwater
Maximum number of resource blocks (RSBs) ever in use
CBT Highwater
Maximum number of Callback Thread Blocks ever in use. For non-clustered, non-DMCM installations, this is typically zero.
Max Local dlk srch
Maximum number of locks examined to resolve
Dlk locks examined
Number of locks examined by the deadlock detection thread
Max rsrc chain len
Maximum length of a resource hash chain
Max lock chain len
Maximum length of a lock hash chain
Max locks per txn
Maximum locks per transaction
Callback Wakeups
Number of times the DMCM callback thread was awakened. Relevant only when the installation has been configured to run with the Distributed Multi-Cache Management (DMCM) protocol.
Callbacks Invoked
Number of times callback functions were invoked to resolve a blocking cache lock. Relevant only when the installation has been configured to run with the Distributed Multi-Cache Management (DMCM) protocol.
Callbacks Ignored
Number of blocking cache locks which had already been released by the time the callback function was invoked. Relevant only when the installation has been configured to run with the Distributed Multi-Cache Management (DMCM) protocol.
CB stash scavenge
Number of times no control blocks (RSB or LKB) were available, so the locking system attempted to scavenge control blocks from another lock list’s stash. Scavenging should be rare, and may be an indication of the need to increase the lock_limit or resource_limit.
Scavenge LLBs
Total number of lock lists that were candidates for stash scavenging, over all scavenges.
Scavenge skip
Total number of lock lists that were scavenge candidates but had to be skipped because they were themselves doing memory allocation