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86th chunk of `doc/src/sgml/monitoring.sgml`
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 the requested lock mode, either exclusive or shared.</entry>
    </row>
    <row>
     <entry><literal>lwlock-release</literal></entry>
     <entry><literal>(char *)</literal></entry>
     <entry>Probe that fires when an LWLock has been released (but note
      that any released waiters have not yet been awakened).
      arg0 is the LWLock's tranche.</entry>
    </row>
    <row>
     <entry><literal>lwlock-wait-start</literal></entry>
     <entry><literal>(char *, LWLockMode)</literal></entry>
     <entry>Probe that fires when an LWLock was not immediately available and
      a server process has begun to wait for the lock to become available.
      arg0 is the LWLock's tranche.
      arg1 is the requested lock mode, either exclusive or shared.</entry>
    </row>
    <row>
     <entry><literal>lwlock-wait-done</literal></entry>
     <entry><literal>(char *, LWLockMode)</literal></entry>
     <entry>Probe that fires when a server process has been released from its
      wait for an LWLock (it does not actually have the lock yet).
      arg0 is the LWLock's tranche.
      arg1 is the requested lock mode, either exclusive or shared.</entry>
    </row>
    <row>
     <entry><literal>lwlock-condacquire</literal></entry>
     <entry><literal>(char *, LWLockMode)</literal></entry>
     <entry>Probe that fires when an LWLock was successfully acquired when the
      caller specified no waiting.
      arg0 is the LWLock's tranche.
      arg1 is the requested lock mode, either exclusive or shared.</entry>
    </row>
    <row>
     <entry><literal>lwlock-condacquire-fail</literal></entry>
     <entry><literal>(char *, LWLockMode)</literal></entry>
     <entry>Probe that fires when an LWLock was not successfully acquired when
      the caller specified no waiting.
      arg0 is the LWLock's tranche.
      arg1 is the requested lock mode, either exclusive or shared.</entry>
    </row>
    <row>
     <entry><literal>lock-wait-start</literal></entry>
     <entry><literal>(unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, LOCKMODE)</literal></entry>
     <entry>Probe that fires when a request for a heavyweight lock (lmgr lock)
      has begun to wait because the lock is not available.
      arg0 through arg3 are the tag fields identifying the object being
      locked.  arg4 indicates the type of object being locked.
      arg5 indicates the lock type being requested.</entry>
    </row>
    <row>
     <entry><literal>lock-wait-done</literal></entry>
     <entry><literal>(unsigned int, unsigned int, unsigned int, unsigned int, unsigned int, LOCKMODE)</literal></entry>
     <entry>Probe that fires when a request for a heavyweight lock (lmgr lock)
      has finished waiting (i.e., has acquired the lock).
      The arguments are the same as for <literal>lock-wait-start</literal>.</entry>
    </row>
    <row>
     <entry><literal>deadlock-found</literal></entry>
     <entry><literal>()</literal></entry>
     <entry>Probe that fires when a deadlock is found by the deadlock
      detector.</entry>
    </row>

   </tbody>
   </tgroup>
  </table>

 <table id="typedefs-table">
  <title>Defined Types Used in Probe Parameters</title>
  <tgroup cols="2">
   <thead>
    <row>
     <entry>Type</entry>
     <entry>Definition</entry>
    </row>
   </thead>

   <tbody>

    <row>
     <entry><type>LocalTransactionId</type></entry>
     <entry><type>unsigned int</type></entry>
    </row>
    <row>
     <entry><type>LWLockMode</type></entry>
     <entry><type>int</type></entry>
    </row>
    <row>
     <entry><type>LOCKMODE</type></entry>
     <entry><type>int</type></entry>
    </row>
    <row>
     <entry><type>BlockNumber</type></entry>
     <entry><type>unsigned int</type></entry>
    </row>
    <row>
     <entry><type>Oid</type></entry>
     <entry><type>unsigned int</type></entry>
    </row>
    <row>
     <entry><type>ForkNumber</type></entry>
     <entry><type>int</type></entry>
    </row>
    <row>
     <entry><type>bool</type></entry>
Title: PostgreSQL DTrace Probes: LWLock and Heavyweight Lock Management, Deadlock Detection, and Defined Types for Probe Parameters
Summary
This section continues the description of PostgreSQL's DTrace probes, focusing on lightweight locks (LWLock) and heavyweight locks (lmgr lock) management, and deadlock detection. LWLock probes include signals for releasing a lock, starting and completing a wait for a lock, and conditional acquisition successes and failures. Heavyweight lock probes signal when a process begins and finishes waiting for a lock, providing information on the object being locked and the requested lock type. A probe also exists for when the deadlock detector finds a deadlock. Finally, the section defines the types used in the probe parameters, such as LocalTransactionId, LWLockMode, LOCKMODE, BlockNumber, Oid, ForkNumber, and bool.