Documentation Source Text

  global nChng aChng
  set aChng($nChng) [list $date $desc $options]
  incr nChng
}

chng {2014-11-?? (3.8.7)} {
<p><b>Performance Enhancements:</b>
<li>Dozens and dozens of micro-optimizations result in 10.5% more work for the same number
    of CPU cycles relative to the previous release. 
    The cumulative performance increase since [version 3.7.17] is 50.2%.
    (Measured using 
    [http://valgrind.org/docs/manual/cg-manual.html|cachegrind] on the
    [http://www.sqlite.org/src/artifact/83f6b3318f7ee|speedtest1.c] workload on
    Ubuntu 13.10 x64 with gcc 4.8.1 and -Os. Your performance may vary.)
<li>Provide the ability for the sorter to start and use auxiliary helper threads in order
    to increase real-time response.  This feature is off by default and may be
    enabled using the [PRAGMA threads] command or the [SQLITE_DEFAULT_WORKER_THREADS]

  whereas the STAT4 enhancement records histogram data from all columns
  of each index.
  The [SQLITE_ENABLE_STAT3] compile-time option is a no-op and is ignored
  if the SQLITE_ENABLE_STAT4 compile-time option is used.
}

COMPILE_OPTION {SQLITE_ENABLE_TREE_EXPLAIN} {
  This option adds support for the [SQLITE_TESTCTRL_EXPLAIN_STMT] test-control
  in the SQLite core.  When the [command-line shell] is also compiled with
  this option, the ".explain" dot-command enables a mode that uses the
  [SQLITE_TESTCTRL_EXPLAIN_STMT] interface to display an ASCII-art diagram
  of the parse tree for each SQL query statement that is run in the shell.
  This mechanism is useful for debugging the SQLite parser and code
  generator.  This whole mechanism is highly experimental and could change
  drastically or be eliminated in future releases of SQLite.
}

COMPILE_OPTION {SQLITE_ENABLE_UPDATE_DELETE_LIMIT} {
  This option enables an optional ORDER BY and LIMIT clause on 
  [UPDATE] and [DELETE] statements.

  <p>If this option is defined, then it must also be