trace_locks

doc html

<p>
        If on, emit information about lock usage.  Information dumped
        includes the type of lock operation, the type of lock and the unique
        identifier of the object being locked or unlocked.  Also included
        are bit masks for the lock types already granted on this object as
        well as for the lock types awaited on this object.  For each lock
        type a count of the number of granted locks and waiting locks is
        also dumped as well as the totals.  An example of the log file output
        is shown here:
</p><pre class="screen">
LOG:  LockAcquire: new: lock(0xb7acd844) id(24688,24696,0,0,0,1)
      grantMask(0) req(0,0,0,0,0,0,0)=0 grant(0,0,0,0,0,0,0)=0
      wait(0) type(AccessShareLock)
LOG:  GrantLock: lock(0xb7acd844) id(24688,24696,0,0,0,1)
      grantMask(2) req(1,0,0,0,0,0,0)=1 grant(1,0,0,0,0,0,0)=1
      wait(0) type(AccessShareLock)
LOG:  UnGrantLock: updated: lock(0xb7acd844) id(24688,24696,0,0,0,1)
      grantMask(0) req(0,0,0,0,0,0,0)=0 grant(0,0,0,0,0,0,0)=0
      wait(0) type(AccessShareLock)
LOG:  CleanUpLock: deleting: lock(0xb7acd844) id(24688,24696,0,0,0,1)
      grantMask(0) req(0,0,0,0,0,0,0)=0 grant(0,0,0,0,0,0,0)=0
      wait(0) type(INVALID)
</pre><p>
        Details of the structure being dumped may be found in
        <code class="filename">src/include/storage/lock.h</code>.
       </p><p>
        This parameter is only available if the <code class="symbol">LOCK_DEBUG</code>
        macro was defined when <span class="productname">PostgreSQL</span> was
        compiled.
       </p>

documentation revision

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