From 18657a960e125336f704ea058e25c27bd3900dcb Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 5 May 2024 19:28:19 +0200 Subject: Adding upstream version 3.40.1. Signed-off-by: Daniel Baumann --- www/c3ref/hard_heap_limit64.html | 192 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 www/c3ref/hard_heap_limit64.html (limited to 'www/c3ref/hard_heap_limit64.html') diff --git a/www/c3ref/hard_heap_limit64.html b/www/c3ref/hard_heap_limit64.html new file mode 100644 index 0000000..7b5a320 --- /dev/null +++ b/www/c3ref/hard_heap_limit64.html @@ -0,0 +1,192 @@ + + + + + +Impose A Limit On Heap Size + + + +
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+Small. Fast. Reliable.
Choose any three. +
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SQLite C Interface

 +

Impose A Limit On Heap Size

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+sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
+sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
+
+

+These interfaces impose limits on the amount of heap memory that will be +by all database connections within a single process.

+ +

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 sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of +N bytes on the amount of memory that will be allocated. The +sqlite3_hard_heap_limit64(N) interface is similar to +sqlite3_soft_heap_limit64(N) except that memory allocations will fail +when the hard heap limit is reached.

+ +

The return value from both sqlite3_soft_heap_limit64() and +sqlite3_hard_heap_limit64() is the size of +the 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 heap limit. Hence, the current +size of heap limits can be determined by invoking +sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).

+ +

Setting the heap limits to zero disables the heap limiter mechanism.

+ +

The soft heap limit may not be greater than the hard heap limit. +If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N) +is invoked with a value of N that is greater than the hard heap limit, +the soft heap limit is set to the value of the hard heap limit. +The soft heap limit is automatically enabled whenever the hard heap +limit is enabled. When sqlite3_hard_heap_limit64(N) is invoked and +the soft heap limit is outside the range of 1..N, then the soft heap +limit is set to N. Invoking sqlite3_soft_heap_limit64(0) when the +hard heap limit is enabled makes the soft heap limit equal to the +hard heap limit.

+ +

The memory allocation limits can also be adjusted using +PRAGMA soft_heap_limit and PRAGMA hard_heap_limit.

+ +

The heap limits are not enforced in the current implementation +if one or more of following conditions are true:

+ +

+ +

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

See also lists of + Objects, + Constants, and + Functions.

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