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82th chunk of `doc/src/sgml/monitoring.sgml`
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  <entry><literal>subtrans-checkpoint-done</literal></entry>
     <entry><literal>(bool)</literal></entry>
     <entry>Probe that fires when the SUBTRANS portion of a checkpoint is
      complete. arg0 has the same meaning as for
      <literal>subtrans-checkpoint-start</literal>.</entry>
    </row>
    <row>
     <entry><literal>multixact-checkpoint-start</literal></entry>
     <entry><literal>(bool)</literal></entry>
     <entry>Probe that fires when the MultiXact portion of a checkpoint is
      started.
      arg0 is true for normal checkpoint, false for shutdown
      checkpoint.</entry>
    </row>
    <row>
     <entry><literal>multixact-checkpoint-done</literal></entry>
     <entry><literal>(bool)</literal></entry>
     <entry>Probe that fires when the MultiXact portion of a checkpoint is
      complete. arg0 has the same meaning as for
      <literal>multixact-checkpoint-start</literal>.</entry>
    </row>
    <row>
     <entry><literal>buffer-checkpoint-start</literal></entry>
     <entry><literal>(int)</literal></entry>
     <entry>Probe that fires when the buffer-writing portion of a checkpoint
      is started.
      arg0 holds the bitwise flags used to distinguish different checkpoint
      types, such as shutdown, immediate or force.</entry>
    </row>
    <row>
     <entry><literal>buffer-sync-start</literal></entry>
     <entry><literal>(int, int)</literal></entry>
     <entry>Probe that fires when we begin to write dirty buffers during
      checkpoint (after identifying which buffers must be written).
      arg0 is the total number of buffers.
      arg1 is the number that are currently dirty and need to be written.</entry>
    </row>
    <row>
     <entry><literal>buffer-sync-written</literal></entry>
     <entry><literal>(int)</literal></entry>
     <entry>Probe that fires after each buffer is written during checkpoint.
      arg0 is the ID number of the buffer.</entry>
    </row>
    <row>
     <entry><literal>buffer-sync-done</literal></entry>
     <entry><literal>(int, int, int)</literal></entry>
     <entry>Probe that fires when all dirty buffers have been written.
      arg0 is the total number of buffers.
      arg1 is the number of buffers actually written by the checkpoint process.
      arg2 is the number that were expected to be written (arg1 of
      <literal>buffer-sync-start</literal>); any difference reflects other processes flushing
      buffers during the checkpoint.</entry>
    </row>
    <row>
     <entry><literal>buffer-checkpoint-sync-start</literal></entry>
     <entry><literal>()</literal></entry>
     <entry>Probe that fires after dirty buffers have been written to the
      kernel, and before starting to issue fsync requests.</entry>
    </row>
    <row>
     <entry><literal>buffer-checkpoint-done</literal></entry>
     <entry><literal>()</literal></entry>
     <entry>Probe that fires when syncing of buffers to disk is
      complete.</entry>
    </row>
    <row>
     <entry><literal>twophase-checkpoint-start</literal></entry>
     <entry><literal>()</literal></entry>
     <entry>Probe that fires when the two-phase portion of a checkpoint is
      started.</entry>
    </row>
    <row>
     <entry><literal>twophase-checkpoint-done</literal></entry>
     <entry><literal>()</literal></entry>
     <entry>Probe that fires when the two-phase portion of a checkpoint is
      complete.</entry>
    </row>
    <row>
     <entry><literal>buffer-extend-start</literal></entry>
     <entry><literal>(ForkNumber, BlockNumber, Oid, Oid, Oid, int, unsigned int)</literal></entry>
     <entry>Probe that fires when a relation extension starts.
       arg0 contains the fork to be extended. arg1, arg2, and arg3 contain the
       tablespace, database, and relation OIDs identifying the relation.  arg4
       is the ID of the backend which created the temporary relation for a
       local buffer, or <symbol>INVALID_PROC_NUMBER</symbol> (-1) for a shared
       buffer. arg5 is the number of blocks the caller
Title: Built-in DTrace Probes in PostgreSQL (Checkpoint and Buffer Management)
Summary
Details on built-in DTrace probes in PostgreSQL related to checkpoint processing, specifically focusing on SUBTRANS, MultiXact, and buffer management phases. It describes probes that fire at the start and end of each phase, providing insights into buffer writing, synchronization, and relation extension. The arguments passed to each probe offer details on checkpoint types, buffer IDs, and relation identifiers.