Documentation Source Text

<li> Added the [sqlite3_create_function_v2()] interface that includes a
     destructor callback.
<li> Added support for [custom r-tree queries] using application-supplied
     callback routines to define the boundary of the query region.
<li> The default page cache strives more diligently to avoid using memory
     beyond what is allocated to it by [SQLITE_CONFIG_PAGECACHE].  Or if
     using page cache is allocating from the heap, it strives to avoid
     going over the [sqlite3_soft_heap_limit()], even if
     [SQLITE_ENABLE_MEMORY_MANAGEMENT] is not set.


}

chng {2010 August 24 (3.7.2)} {
<li> Fix an <a href="http://www.sqlite.org/src/info/5e10420e8d">
     old and very obscure bug</a> that can lead to corruption of the
     database [free-page list] when [incremental_vacuum] is used.
}

}

COMPILE_OPTION {SQLITE_ENABLE_MEMORY_MANAGEMENT} {
  This option adds extra logic to SQLite that allows it to release unused
  memory upon request.  This option must be enabled in order for the
  [sqlite3_release_memory()] interface to work.  If this compile-time
  option is not used, the [sqlite3_release_memory()] interface is a 
  no-op.  Since [sqlite3_soft_heap_limit()] depends on
  [sqlite3_release_memory()], this option is also necessary for
  the correct operation of [sqlite3_soft_heap_limit()].
}

COMPILE_OPTION {SQLITE_ENABLE_MEMSYS3} {
  This option includes code in SQLite that implements an alternative
  memory allocator.  This alternative memory allocator is only engaged
  when the [SQLITE_CONFIG_HEAP] option to [sqlite3_config()] is used to
  supply a large chunk of memory from which all memory allocations are

The second [SQLITE_CONFIG_MEMSTATUS] setting disables the mechanism
in SQLite that tracks the total size of all outstanding memory
allocation requests.  This omits the need to mutex each call
to [sqlite3_malloc()] and [sqlite3_free()], which saves a huge
number of mutex operations.  But a consequence of disabling the
memory statistics mechanism is that the 
[sqlite3_memory_used()], [sqlite3_memory_highwater()], and
[sqlite3_soft_heap_limit()] interfaces cease to work.
</p>

<p>SQLite uses pthreads for its mutex implementation on Unix and
SQLite requires a recursive mutex.  Most modern pthread implementations
support recursive mutexes, but not all do.  For systems that do not
support recursive mutexes, it is recommended that applications operate
in single-threaded mode only.  If this is not possible, SQLite provides

the application cooperates, SQLite will never leak memory.  This is
true even in the face of memory allocation failures or other system
errors.
</p></li>

<li><p>
<b>Memory usage limits.</b>
The [sqlite3_soft_heap_limit()] mechanism allows the application to
set a memory usage limit that SQLite strives to stay below.  SQLite
will attempt to reuse memory from its caches rather than allocation new
memory as it approaches the soft limit.
</p></li>

<li><p>
<b>Zero-malloc option</b>