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SQLITE3_SOFT_HEAP_LIMIT64(3)                          Library Functions Manual

NAME
     sqlite3_soft_heap_limit64 - Impose A Limit On Heap Size

SYNOPSIS
     sqlite3_int64
     sqlite3_soft_heap_limit64(sqlite3_int64 N);

DESCRIPTION
     The sqlite3_soft_heap_limit64() interface sets and/or queries the soft
     limit on the amount of heap memory that may be allocated by SQLite.
     SQLite strives to keep heap memory utilization below the soft heap limit
     by reducing the number of pages held in the page cache as heap memory
     usages approaches the limit.  The soft heap limit is "soft" because even
     though SQLite strives to stay below the limit, it will exceed the limit
     rather than generate an SQLITE_NOMEM error.  In other words, the soft
     heap limit is advisory only.

     The return value from sqlite3_soft_heap_limit64() is the size of the soft
     heap limit prior to the call, or negative in the case of an error.  If
     the argument N is negative then no change is made to the soft heap limit.
     Hence, the current size of the soft heap limit can be determined by
     invoking sqlite3_soft_heap_limit64() with a negative argument.

     If the argument N is zero then the soft heap limit is disabled.

     The soft heap limit is not enforced in the current implementation if one
     or more of following conditions are true:

     ⊕   The soft heap limit is set to zero.

     ⊕   Memory accounting is disabled using a combination of the
         sqlite3_config(SQLITE_CONFIG_MEMSTATUS,...) start-time option and the
         SQLITE_DEFAULT_MEMSTATUS compile-time option.

     ⊕   An alternative page cache implementation is specified using
         sqlite3_config(SQLITE_CONFIG_PCACHE2,...).

     ⊕   The page cache allocates from its own memory pool supplied by
         sqlite3_config(SQLITE_CONFIG_PAGECACHE,...) rather than from the
         heap.

     Beginning with SQLite version 3.7.3 (dateof:3.7.3), the soft heap limit
     is enforced regardless of whether or not the
     SQLITE_ENABLE_MEMORY_MANAGEMENT compile-time option is invoked.  With
     SQLITE_ENABLE_MEMORY_MANAGEMENT, the soft heap limit is enforced on every
     memory allocation.  Without SQLITE_ENABLE_MEMORY_MANAGEMENT, the soft
     heap limit is only enforced when memory is allocated by the page cache.
     Testing suggests that because the page cache is the predominate memory
     user in SQLite, most applications will achieve adequate soft heap limit
     enforcement without the use of SQLITE_ENABLE_MEMORY_MANAGEMENT.

     The circumstances under which SQLite will enforce the soft heap limit may
     changes in future releases of SQLite.

SEE ALSO
     sqlite3_config(3), SQLITE_CONFIG_SINGLETHREAD(3), SQLITE_OK(3)

NetBSD 9.99                    December 19, 2018                   NetBSD 9.99