The first argument ("buf") is a ** pointer to a memory buffer to use for lookaside memory. -** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb -** may be NULL in which case SQLite will allocate the -** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the -** size of each lookaside buffer slot. ^The third argument is the number of -** slots. The size of the buffer in the first argument must be greater than -** or equal to the product of the second and third arguments. The buffer -** must be aligned to an 8-byte boundary. ^If the second argument to -** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally -** rounded down to the next smaller multiple of 8. ^(The lookaside memory +** The first argument may be NULL in which case SQLite will allocate the +** lookaside buffer itself using [sqlite3_malloc()]. +**
The second argument ("sz") is the +** size of each lookaside buffer slot. Lookaside is disabled if "sz" +** is less than 8. The "sz" argument should be a multiple of 8 less than +** 65536. If "sz" does not meet this constraint, it is reduced in size until +** it does. +**
The third argument ("cnt") is the number of slots. Lookaside is disabled +** if "cnt"is less than 1. The "cnt" value will be reduced, if necessary, so +** that the product of "sz" and "cnt" does not exceed 2,147,418,112. The "cnt" +** parameter is usually chosen so that the product of "sz" and "cnt" is less +** than 1,000,000. +**
If the "buf" argument is not NULL, then it must +** point to a memory buffer with a size that is greater than +** or equal to the product of "sz" and "cnt". +** The buffer must be aligned to an 8-byte boundary. +** The lookaside memory ** configuration for a database connection can only be changed when that ** connection is not currently using lookaside memory, or in other words -** when the "current value" returned by -** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero. +** when the value returned by [SQLITE_DBSTATUS_LOOKASIDE_USED] is zero. ** Any attempt to change the lookaside memory configuration when lookaside ** memory is in use leaves the configuration unchanged and returns -** [SQLITE_BUSY].)^
+** The [SQLITE_CONFIG_LOOKASIDE] configuration option can be used to set the +** default lookaside configuration at initialization. The +** [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to set the default lookaside +** configuration at compile-time. Typical values for lookaside are 1200 for +** "sz" and 40 to 100 for "cnt". +** ** ** [[SQLITE_DBCONFIG_ENABLE_FKEY]] **
This option takes two arguments: an integer and a pointer to -** an integer.. The first argument is 1, 0, or -1 to enable, disable, or +** an integer. The first argument is 1, 0, or -1 to enable, disable, or ** leave unchanged the statement scanstatus option. If the second argument ** is not NULL, then the value of the statement scanstatus setting after ** processing the first argument is written into the integer that the second @@ -2885,8 +2937,8 @@ struct sqlite3_mem_methods { **
Most of the SQLITE_DBCONFIG options take two arguments, so that the ** overall call to [sqlite3_db_config()] has a total of four parameters. -** The first argument (the third parameter to sqlite3_db_config()) is a integer. +** The first argument (the third parameter to sqlite3_db_config()) is an integer. ** The second argument is a pointer to an integer. If the first argument is 1, ** then the option becomes enabled. If the first integer argument is 0, then the ** option is disabled. If the first argument is -1, then the option setting @@ -3210,7 +3262,7 @@ SQLITE_API int sqlite3_is_interrupted(sqlite3*); ** ^These routines return 0 if the statement is incomplete. ^If a ** memory allocation fails, then SQLITE_NOMEM is returned. ** -** ^These routines do not parse the SQL statements thus +** ^These routines do not parse the SQL statements and thus ** will not detect syntactically incorrect SQL. ** ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior @@ -3312,6 +3364,44 @@ SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); */ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); +/* +** CAPI3REF: Set the Setlk Timeout +** METHOD: sqlite3 +** +** This routine is only useful in SQLITE_ENABLE_SETLK_TIMEOUT builds. If +** the VFS supports blocking locks, it sets the timeout in ms used by +** eligible locks taken on wal mode databases by the specified database +** handle. In non-SQLITE_ENABLE_SETLK_TIMEOUT builds, or if the VFS does +** not support blocking locks, this function is a no-op. +** +** Passing 0 to this function disables blocking locks altogether. Passing +** -1 to this function requests that the VFS blocks for a long time - +** indefinitely if possible. The results of passing any other negative value +** are undefined. +** +** Internally, each SQLite database handle stores two timeout values - the +** busy-timeout (used for rollback mode databases, or if the VFS does not +** support blocking locks) and the setlk-timeout (used for blocking locks +** on wal-mode databases). The sqlite3_busy_timeout() method sets both +** values, this function sets only the setlk-timeout value. Therefore, +** to configure separate busy-timeout and setlk-timeout values for a single +** database handle, call sqlite3_busy_timeout() followed by this function. +** +** Whenever the number of connections to a wal mode database falls from +** 1 to 0, the last connection takes an exclusive lock on the database, +** then checkpoints and deletes the wal file. While it is doing this, any +** new connection that tries to read from the database fails with an +** SQLITE_BUSY error. Or, if the SQLITE_SETLK_BLOCK_ON_CONNECT flag is +** passed to this API, the new connection blocks until the exclusive lock +** has been released. +*/ +SQLITE_API int sqlite3_setlk_timeout(sqlite3*, int ms, int flags); + +/* +** CAPI3REF: Flags for sqlite3_setlk_timeout() +*/ +#define SQLITE_SETLK_BLOCK_ON_CONNECT 0x01 + /* ** CAPI3REF: Convenience Routines For Running Queries ** METHOD: sqlite3 @@ -3319,7 +3409,7 @@ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); ** This is a legacy interface that is preserved for backwards compatibility. ** Use of this interface is not recommended. ** -** Definition: A result table is memory data structure created by the +** Definition: A result table is a memory data structure created by the ** [sqlite3_get_table()] interface. A result table records the ** complete query results from one or more queries. ** @@ -3462,7 +3552,7 @@ SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); ** ^Calling sqlite3_free() with a pointer previously returned ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so ** that it might be reused. ^The sqlite3_free() routine is -** a no-op if is called with a NULL pointer. Passing a NULL pointer +** a no-op if it is called with a NULL pointer. Passing a NULL pointer ** to sqlite3_free() is harmless. After being freed, memory ** should neither be read nor written. Even reading previously freed ** memory might result in a segmentation fault or other severe error. @@ -3480,13 +3570,13 @@ SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); ** sqlite3_free(X). ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation ** of at least N bytes in size or NULL if insufficient memory is available. -** ^If M is the size of the prior allocation, then min(N,M) bytes -** of the prior allocation are copied into the beginning of buffer returned +** ^If M is the size of the prior allocation, then min(N,M) bytes of the +** prior allocation are copied into the beginning of the buffer returned ** by sqlite3_realloc(X,N) and the prior allocation is freed. ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the ** prior allocation is not freed. ** -** ^The sqlite3_realloc64(X,N) interfaces works the same as +** ^The sqlite3_realloc64(X,N) interface works the same as ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead ** of a 32-bit signed integer. ** @@ -3536,7 +3626,7 @@ SQLITE_API sqlite3_uint64 sqlite3_msize(void*); ** was last reset. ^The values returned by [sqlite3_memory_used()] and ** [sqlite3_memory_highwater()] include any overhead ** added by SQLite in its implementation of [sqlite3_malloc()], -** but not overhead added by the any underlying system library +** but not overhead added by any underlying system library ** routines that [sqlite3_malloc()] may call. ** ** ^The memory high-water mark is reset to the current value of @@ -3988,7 +4078,7 @@ SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); ** there is no harm in trying.) ** ** ^(
** int xEntryPoint( @@ -7860,7 +7983,7 @@ struct sqlite3_module { ** virtual table and might not be checked again by the byte code.)^ ^(The ** aConstraintUsage[].omit flag is an optimization hint. When the omit flag ** is left in its default setting of false, the constraint will always be -** checked separately in byte code. If the omit flag is change to true, then +** checked separately in byte code. If the omit flag is changed to true, then ** the constraint may or may not be checked in byte code. In other words, ** when the omit flag is true there is no guarantee that the constraint will ** not be checked again using byte code.)^ @@ -7886,7 +8009,7 @@ struct sqlite3_module { ** The xBestIndex method may optionally populate the idxFlags field with a ** mask of SQLITE_INDEX_SCAN_* flags. One such flag is ** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN] -** output to show the idxNum has hex instead of as decimal. Another flag is +** output to show the idxNum as hex instead of as decimal. Another flag is ** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will ** return at most one row. ** @@ -8027,7 +8150,7 @@ struct sqlite3_index_info { ** the implementation of the [virtual table module]. ^The fourth ** parameter is an arbitrary client data pointer that is passed through ** into the [xCreate] and [xConnect] methods of the virtual table module -** when a new virtual table is be being created or reinitialized. +** when a new virtual table is being created or reinitialized. ** ** ^The sqlite3_create_module_v2() interface has a fifth parameter which ** is a pointer to a destructor for the pClientData. ^SQLite will @@ -8192,7 +8315,7 @@ typedef struct sqlite3_blob sqlite3_blob; ** in *ppBlob. Otherwise an [error code] is returned and, unless the error ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided ** the API is not misused, it is always safe to call [sqlite3_blob_close()] -** on *ppBlob after this function it returns. +** on *ppBlob after this function returns. ** ** This function fails with SQLITE_ERROR if any of the following are true: **@@ -8312,7 +8435,7 @@ SQLITE_API int sqlite3_blob_close(sqlite3_blob *); ** ** ^Returns the size in bytes of the BLOB accessible via the ** successfully opened [BLOB handle] in its only argument. ^The -** incremental blob I/O routines can only read or overwriting existing +** incremental blob I/O routines can only read or overwrite existing ** blob content; they cannot change the size of a blob. ** ** This routine only works on a [BLOB handle] which has been created @@ -8462,7 +8585,7 @@ SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); ** ^The sqlite3_mutex_alloc() routine allocates a new ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() ** routine returns NULL if it is unable to allocate the requested -** mutex. The argument to sqlite3_mutex_alloc() must one of these +** mutex. The argument to sqlite3_mutex_alloc() must be one of these ** integer constants: ** **
@@ -8695,7 +8818,7 @@ SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); ** CAPI3REF: Retrieve the mutex for a database connection ** METHOD: sqlite3 ** -** ^This interface returns a pointer the [sqlite3_mutex] object that +** ^This interface returns a pointer to the [sqlite3_mutex] object that ** serializes access to the [database connection] given in the argument ** when the [threading mode] is Serialized. ** ^If the [threading mode] is Single-thread or Multi-thread then this @@ -8818,7 +8941,7 @@ SQLITE_API int sqlite3_test_control(int op, ...); ** CAPI3REF: SQL Keyword Checking ** ** These routines provide access to the set of SQL language keywords -** recognized by SQLite. Applications can uses these routines to determine +** recognized by SQLite. Applications can use these routines to determine ** whether or not a specific identifier needs to be escaped (for example, ** by enclosing in double-quotes) so as not to confuse the parser. ** @@ -8986,7 +9109,7 @@ SQLITE_API void sqlite3_str_reset(sqlite3_str*); ** content of the dynamic string under construction in X. The value ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X ** and might be freed or altered by any subsequent method on the same -** [sqlite3_str] object. Applications must not used the pointer returned +** [sqlite3_str] object. Applications must not use the pointer returned by ** [sqlite3_str_value(X)] after any subsequent method call on the same ** object. ^Applications may change the content of the string returned ** by [sqlite3_str_value(X)] as long as they do not write into any bytes @@ -9072,7 +9195,7 @@ SQLITE_API int sqlite3_status64( ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] ** buffer and where forced to overflow to [sqlite3_malloc()]. The ** returned value includes allocations that overflowed because they -** where too large (they were larger than the "sz" parameter to +** were too large (they were larger than the "sz" parameter to ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because ** no space was left in the page cache.
+** ^(There is overlap between the quantities measured by this parameter +** (SQLITE_DBSTATUS_CACHE_WRITE) and SQLITE_DBSTATUS_TEMPBUF_SPILL. +** Resetting one will reduce the other.)^ **
+** ^(There is overlap between the quantities measured by this parameter +** (SQLITE_DBSTATUS_TEMPBUF_SPILL) and SQLITE_DBSTATUS_CACHE_WRITE. +** Resetting one will reduce the other.)^ **
| createFlag | Behavior when page is not already in cache ** |
|---|---|
| 0 | Do not allocate a new page. Return NULL. -** |
| 1 | Allocate a new page if it easy and convenient to do so. +** |
| 1 | Allocate a new page if it is easy and convenient to do so. ** Otherwise return NULL. ** |
| 2 | Make every effort to allocate a new page. Only return
** NULL if allocating a new page is effectively impossible.
@@ -9517,7 +9668,7 @@ struct sqlite3_pcache_page {
** as its second argument. If the third parameter, discard, is non-zero,
** then the page must be evicted from the cache.
** ^If the discard parameter is
-** zero, then the page may be discarded or retained at the discretion of
+** zero, then the page may be discarded or retained at the discretion of the
** page cache implementation. ^The page cache implementation
** may choose to evict unpinned pages at any time.
**
@@ -9535,7 +9686,7 @@ struct sqlite3_pcache_page {
** When SQLite calls the xTruncate() method, the cache must discard all
** existing cache entries with page numbers (keys) greater than or equal
** to the value of the iLimit parameter passed to xTruncate(). If any
-** of these pages are pinned, they are implicitly unpinned, meaning that
+** of these pages are pinned, they become implicitly unpinned, meaning that
** they can be safely discarded.
**
** [[the xDestroy() page cache method]]
@@ -9715,7 +9866,7 @@ typedef struct sqlite3_backup sqlite3_backup;
** external process or via a database connection other than the one being
** used by the backup operation, then the backup will be automatically
** restarted by the next call to sqlite3_backup_step(). ^If the source
-** database is modified by the using the same database connection as is used
+** database is modified by using the same database connection as is used
** by the backup operation, then the backup database is automatically
** updated at the same time.
**
@@ -9732,7 +9883,7 @@ typedef struct sqlite3_backup sqlite3_backup;
** and may not be used following a call to sqlite3_backup_finish().
**
** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
-** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() errors occurred, regardless of whether or not
** sqlite3_backup_step() completed.
** ^If an out-of-memory condition or IO error occurred during any prior
** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
@@ -9834,7 +9985,7 @@ SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
** application receives an SQLITE_LOCKED error, it may call the
** sqlite3_unlock_notify() method with the blocked connection handle as
** the first argument to register for a callback that will be invoked
-** when the blocking connections current transaction is concluded. ^The
+** when the blocking connection's current transaction is concluded. ^The
** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
** call that concludes the blocking connection's transaction.
**
@@ -9854,7 +10005,7 @@ SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
** blocked connection already has a registered unlock-notify callback,
** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
** called with a NULL pointer as its second argument, then any existing
-** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback is canceled. ^The blocked connection's
** unlock-notify callback may also be canceled by closing the blocked
** connection using [sqlite3_close()].
**
@@ -10024,7 +10175,7 @@ SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
** is the number of pages currently in the write-ahead log file,
** including those that were just committed.
**
-** The callback function should normally return [SQLITE_OK]. ^If an error
+** ^The callback function should normally return [SQLITE_OK]. ^If an error
** code is returned, that error will propagate back up through the
** SQLite code base to cause the statement that provoked the callback
** to report an error, though the commit will have still occurred. If the
@@ -10032,13 +10183,26 @@ SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
** that does not correspond to any valid SQLite error code, the results
** are undefined.
**
-** A single database handle may have at most a single write-ahead log callback
-** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
-** previously registered write-ahead log callback. ^The return value is
-** a copy of the third parameter from the previous call, if any, or 0.
-** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
-** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
-** overwrite any prior [sqlite3_wal_hook()] settings.
+** ^A single database handle may have at most a single write-ahead log
+** callback registered at one time. ^Calling [sqlite3_wal_hook()]
+** replaces the default behavior or previously registered write-ahead
+** log callback.
+**
+** ^The return value is a copy of the third parameter from the
+** previous call, if any, or 0.
+**
+** ^The [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and
+** will overwrite any prior [sqlite3_wal_hook()] settings.
+**
+** ^If a write-ahead log callback is set using this function then
+** [sqlite3_wal_checkpoint_v2()] or [PRAGMA wal_checkpoint]
+** should be invoked periodically to keep the write-ahead log file
+** from growing without bound.
+**
+** ^Passing a NULL pointer for the callback disables automatic
+** checkpointing entirely. To re-enable the default behavior, call
+** sqlite3_wal_autocheckpoint(db,1000) or use [PRAGMA wal_checkpoint].
*/
SQLITE_API void *sqlite3_wal_hook(
sqlite3*,
@@ -10055,7 +10219,7 @@ SQLITE_API void *sqlite3_wal_hook(
** to automatically [checkpoint]
** after committing a transaction if there are N or
** more frames in the [write-ahead log] file. ^Passing zero or
-** a negative value as the nFrame parameter disables automatic
+** a negative value as the N parameter disables automatic
** checkpoints entirely.
**
** ^The callback registered by this function replaces any existing callback
@@ -10071,9 +10235,10 @@ SQLITE_API void *sqlite3_wal_hook(
**
** ^Every new [database connection] defaults to having the auto-checkpoint
** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
-** pages. The use of this interface
-** is only necessary if the default setting is found to be suboptimal
-** for a particular application.
+** pages.
+**
+** ^The use of this interface is only necessary if the default setting
+** is found to be suboptimal for a particular application.
*/
SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
@@ -10138,6 +10303,11 @@ SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
** addition that it also truncates the log file to zero bytes just prior
** to a successful return.
+**
+** |
The first argument ("buf") is a ** pointer to a memory buffer to use for lookaside memory. -** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb -** may be NULL in which case SQLite will allocate the -** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the -** size of each lookaside buffer slot. ^The third argument is the number of -** slots. The size of the buffer in the first argument must be greater than -** or equal to the product of the second and third arguments. The buffer -** must be aligned to an 8-byte boundary. ^If the second argument to -** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally -** rounded down to the next smaller multiple of 8. ^(The lookaside memory +** The first argument may be NULL in which case SQLite will allocate the +** lookaside buffer itself using [sqlite3_malloc()]. +**
The second argument ("sz") is the +** size of each lookaside buffer slot. Lookaside is disabled if "sz" +** is less than 8. The "sz" argument should be a multiple of 8 less than +** 65536. If "sz" does not meet this constraint, it is reduced in size until +** it does. +**
The third argument ("cnt") is the number of slots. Lookaside is disabled +** if "cnt"is less than 1. The "cnt" value will be reduced, if necessary, so +** that the product of "sz" and "cnt" does not exceed 2,147,418,112. The "cnt" +** parameter is usually chosen so that the product of "sz" and "cnt" is less +** than 1,000,000. +**
If the "buf" argument is not NULL, then it must +** point to a memory buffer with a size that is greater than +** or equal to the product of "sz" and "cnt". +** The buffer must be aligned to an 8-byte boundary. +** The lookaside memory ** configuration for a database connection can only be changed when that ** connection is not currently using lookaside memory, or in other words -** when the "current value" returned by -** [sqlite3_db_status](D,[SQLITE_DBSTATUS_LOOKASIDE_USED],...) is zero. +** when the value returned by [SQLITE_DBSTATUS_LOOKASIDE_USED] is zero. ** Any attempt to change the lookaside memory configuration when lookaside ** memory is in use leaves the configuration unchanged and returns -** [SQLITE_BUSY].)^
+** The [SQLITE_CONFIG_LOOKASIDE] configuration option can be used to set the +** default lookaside configuration at initialization. The +** [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to set the default lookaside +** configuration at compile-time. Typical values for lookaside are 1200 for +** "sz" and 40 to 100 for "cnt". +** ** ** [[SQLITE_DBCONFIG_ENABLE_FKEY]] **
This option takes two arguments: an integer and a pointer to -** an integer.. The first argument is 1, 0, or -1 to enable, disable, or +** an integer. The first argument is 1, 0, or -1 to enable, disable, or ** leave unchanged the statement scanstatus option. If the second argument ** is not NULL, then the value of the statement scanstatus setting after ** processing the first argument is written into the integer that the second @@ -2566,8 +2616,8 @@ struct sqlite3_mem_methods { **
Most of the SQLITE_DBCONFIG options take two arguments, so that the ** overall call to [sqlite3_db_config()] has a total of four parameters. -** The first argument (the third parameter to sqlite3_db_config()) is a integer. +** The first argument (the third parameter to sqlite3_db_config()) is an integer. ** The second argument is a pointer to an integer. If the first argument is 1, ** then the option becomes enabled. If the first integer argument is 0, then the ** option is disabled. If the first argument is -1, then the option setting @@ -2891,7 +2941,7 @@ SQLITE_API int sqlite3_is_interrupted(sqlite3*); ** ^These routines return 0 if the statement is incomplete. ^If a ** memory allocation fails, then SQLITE_NOMEM is returned. ** -** ^These routines do not parse the SQL statements thus +** ^These routines do not parse the SQL statements and thus ** will not detect syntactically incorrect SQL. ** ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior @@ -2993,6 +3043,44 @@ SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); */ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); +/* +** CAPI3REF: Set the Setlk Timeout +** METHOD: sqlite3 +** +** This routine is only useful in SQLITE_ENABLE_SETLK_TIMEOUT builds. If +** the VFS supports blocking locks, it sets the timeout in ms used by +** eligible locks taken on wal mode databases by the specified database +** handle. In non-SQLITE_ENABLE_SETLK_TIMEOUT builds, or if the VFS does +** not support blocking locks, this function is a no-op. +** +** Passing 0 to this function disables blocking locks altogether. Passing +** -1 to this function requests that the VFS blocks for a long time - +** indefinitely if possible. The results of passing any other negative value +** are undefined. +** +** Internally, each SQLite database handle stores two timeout values - the +** busy-timeout (used for rollback mode databases, or if the VFS does not +** support blocking locks) and the setlk-timeout (used for blocking locks +** on wal-mode databases). The sqlite3_busy_timeout() method sets both +** values, this function sets only the setlk-timeout value. Therefore, +** to configure separate busy-timeout and setlk-timeout values for a single +** database handle, call sqlite3_busy_timeout() followed by this function. +** +** Whenever the number of connections to a wal mode database falls from +** 1 to 0, the last connection takes an exclusive lock on the database, +** then checkpoints and deletes the wal file. While it is doing this, any +** new connection that tries to read from the database fails with an +** SQLITE_BUSY error. Or, if the SQLITE_SETLK_BLOCK_ON_CONNECT flag is +** passed to this API, the new connection blocks until the exclusive lock +** has been released. +*/ +SQLITE_API int sqlite3_setlk_timeout(sqlite3*, int ms, int flags); + +/* +** CAPI3REF: Flags for sqlite3_setlk_timeout() +*/ +#define SQLITE_SETLK_BLOCK_ON_CONNECT 0x01 + /* ** CAPI3REF: Convenience Routines For Running Queries ** METHOD: sqlite3 @@ -3000,7 +3088,7 @@ SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); ** This is a legacy interface that is preserved for backwards compatibility. ** Use of this interface is not recommended. ** -** Definition: A result table is memory data structure created by the +** Definition: A result table is a memory data structure created by the ** [sqlite3_get_table()] interface. A result table records the ** complete query results from one or more queries. ** @@ -3143,7 +3231,7 @@ SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); ** ^Calling sqlite3_free() with a pointer previously returned ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so ** that it might be reused. ^The sqlite3_free() routine is -** a no-op if is called with a NULL pointer. Passing a NULL pointer +** a no-op if it is called with a NULL pointer. Passing a NULL pointer ** to sqlite3_free() is harmless. After being freed, memory ** should neither be read nor written. Even reading previously freed ** memory might result in a segmentation fault or other severe error. @@ -3161,13 +3249,13 @@ SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); ** sqlite3_free(X). ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation ** of at least N bytes in size or NULL if insufficient memory is available. -** ^If M is the size of the prior allocation, then min(N,M) bytes -** of the prior allocation are copied into the beginning of buffer returned +** ^If M is the size of the prior allocation, then min(N,M) bytes of the +** prior allocation are copied into the beginning of the buffer returned ** by sqlite3_realloc(X,N) and the prior allocation is freed. ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the ** prior allocation is not freed. ** -** ^The sqlite3_realloc64(X,N) interfaces works the same as +** ^The sqlite3_realloc64(X,N) interface works the same as ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead ** of a 32-bit signed integer. ** @@ -3217,7 +3305,7 @@ SQLITE_API sqlite3_uint64 sqlite3_msize(void*); ** was last reset. ^The values returned by [sqlite3_memory_used()] and ** [sqlite3_memory_highwater()] include any overhead ** added by SQLite in its implementation of [sqlite3_malloc()], -** but not overhead added by the any underlying system library +** but not overhead added by any underlying system library ** routines that [sqlite3_malloc()] may call. ** ** ^The memory high-water mark is reset to the current value of @@ -3669,7 +3757,7 @@ SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); ** there is no harm in trying.) ** ** ^(
** int xEntryPoint( @@ -7541,7 +7662,7 @@ struct sqlite3_module { ** virtual table and might not be checked again by the byte code.)^ ^(The ** aConstraintUsage[].omit flag is an optimization hint. When the omit flag ** is left in its default setting of false, the constraint will always be -** checked separately in byte code. If the omit flag is change to true, then +** checked separately in byte code. If the omit flag is changed to true, then ** the constraint may or may not be checked in byte code. In other words, ** when the omit flag is true there is no guarantee that the constraint will ** not be checked again using byte code.)^ @@ -7567,7 +7688,7 @@ struct sqlite3_module { ** The xBestIndex method may optionally populate the idxFlags field with a ** mask of SQLITE_INDEX_SCAN_* flags. One such flag is ** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN] -** output to show the idxNum has hex instead of as decimal. Another flag is +** output to show the idxNum as hex instead of as decimal. Another flag is ** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will ** return at most one row. ** @@ -7708,7 +7829,7 @@ struct sqlite3_index_info { ** the implementation of the [virtual table module]. ^The fourth ** parameter is an arbitrary client data pointer that is passed through ** into the [xCreate] and [xConnect] methods of the virtual table module -** when a new virtual table is be being created or reinitialized. +** when a new virtual table is being created or reinitialized. ** ** ^The sqlite3_create_module_v2() interface has a fifth parameter which ** is a pointer to a destructor for the pClientData. ^SQLite will @@ -7873,7 +7994,7 @@ typedef struct sqlite3_blob sqlite3_blob; ** in *ppBlob. Otherwise an [error code] is returned and, unless the error ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided ** the API is not misused, it is always safe to call [sqlite3_blob_close()] -** on *ppBlob after this function it returns. +** on *ppBlob after this function returns. ** ** This function fails with SQLITE_ERROR if any of the following are true: **@@ -7993,7 +8114,7 @@ SQLITE_API int sqlite3_blob_close(sqlite3_blob *); ** ** ^Returns the size in bytes of the BLOB accessible via the ** successfully opened [BLOB handle] in its only argument. ^The -** incremental blob I/O routines can only read or overwriting existing +** incremental blob I/O routines can only read or overwrite existing ** blob content; they cannot change the size of a blob. ** ** This routine only works on a [BLOB handle] which has been created @@ -8143,7 +8264,7 @@ SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); ** ^The sqlite3_mutex_alloc() routine allocates a new ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() ** routine returns NULL if it is unable to allocate the requested -** mutex. The argument to sqlite3_mutex_alloc() must one of these +** mutex. The argument to sqlite3_mutex_alloc() must be one of these ** integer constants: ** **
@@ -8376,7 +8497,7 @@ SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); ** CAPI3REF: Retrieve the mutex for a database connection ** METHOD: sqlite3 ** -** ^This interface returns a pointer the [sqlite3_mutex] object that +** ^This interface returns a pointer to the [sqlite3_mutex] object that ** serializes access to the [database connection] given in the argument ** when the [threading mode] is Serialized. ** ^If the [threading mode] is Single-thread or Multi-thread then this @@ -8499,7 +8620,7 @@ SQLITE_API int sqlite3_test_control(int op, ...); ** CAPI3REF: SQL Keyword Checking ** ** These routines provide access to the set of SQL language keywords -** recognized by SQLite. Applications can uses these routines to determine +** recognized by SQLite. Applications can use these routines to determine ** whether or not a specific identifier needs to be escaped (for example, ** by enclosing in double-quotes) so as not to confuse the parser. ** @@ -8667,7 +8788,7 @@ SQLITE_API void sqlite3_str_reset(sqlite3_str*); ** content of the dynamic string under construction in X. The value ** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X ** and might be freed or altered by any subsequent method on the same -** [sqlite3_str] object. Applications must not used the pointer returned +** [sqlite3_str] object. Applications must not use the pointer returned by ** [sqlite3_str_value(X)] after any subsequent method call on the same ** object. ^Applications may change the content of the string returned ** by [sqlite3_str_value(X)] as long as they do not write into any bytes @@ -8753,7 +8874,7 @@ SQLITE_API int sqlite3_status64( ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] ** buffer and where forced to overflow to [sqlite3_malloc()]. The ** returned value includes allocations that overflowed because they -** where too large (they were larger than the "sz" parameter to +** were too large (they were larger than the "sz" parameter to ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because ** no space was left in the page cache.
+** ^(There is overlap between the quantities measured by this parameter +** (SQLITE_DBSTATUS_CACHE_WRITE) and SQLITE_DBSTATUS_TEMPBUF_SPILL. +** Resetting one will reduce the other.)^ **
+** ^(There is overlap between the quantities measured by this parameter +** (SQLITE_DBSTATUS_TEMPBUF_SPILL) and SQLITE_DBSTATUS_CACHE_WRITE. +** Resetting one will reduce the other.)^ **
| createFlag | Behavior when page is not already in cache ** |
|---|---|
| 0 | Do not allocate a new page. Return NULL. -** |
| 1 | Allocate a new page if it easy and convenient to do so. +** |
| 1 | Allocate a new page if it is easy and convenient to do so. ** Otherwise return NULL. ** |
| 2 | Make every effort to allocate a new page. Only return
** NULL if allocating a new page is effectively impossible.
@@ -9198,7 +9347,7 @@ struct sqlite3_pcache_page {
** as its second argument. If the third parameter, discard, is non-zero,
** then the page must be evicted from the cache.
** ^If the discard parameter is
-** zero, then the page may be discarded or retained at the discretion of
+** zero, then the page may be discarded or retained at the discretion of the
** page cache implementation. ^The page cache implementation
** may choose to evict unpinned pages at any time.
**
@@ -9216,7 +9365,7 @@ struct sqlite3_pcache_page {
** When SQLite calls the xTruncate() method, the cache must discard all
** existing cache entries with page numbers (keys) greater than or equal
** to the value of the iLimit parameter passed to xTruncate(). If any
-** of these pages are pinned, they are implicitly unpinned, meaning that
+** of these pages are pinned, they become implicitly unpinned, meaning that
** they can be safely discarded.
**
** [[the xDestroy() page cache method]]
@@ -9396,7 +9545,7 @@ typedef struct sqlite3_backup sqlite3_backup;
** external process or via a database connection other than the one being
** used by the backup operation, then the backup will be automatically
** restarted by the next call to sqlite3_backup_step(). ^If the source
-** database is modified by the using the same database connection as is used
+** database is modified by using the same database connection as is used
** by the backup operation, then the backup database is automatically
** updated at the same time.
**
@@ -9413,7 +9562,7 @@ typedef struct sqlite3_backup sqlite3_backup;
** and may not be used following a call to sqlite3_backup_finish().
**
** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
-** sqlite3_backup_step() errors occurred, regardless or whether or not
+** sqlite3_backup_step() errors occurred, regardless of whether or not
** sqlite3_backup_step() completed.
** ^If an out-of-memory condition or IO error occurred during any prior
** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
@@ -9515,7 +9664,7 @@ SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
** application receives an SQLITE_LOCKED error, it may call the
** sqlite3_unlock_notify() method with the blocked connection handle as
** the first argument to register for a callback that will be invoked
-** when the blocking connections current transaction is concluded. ^The
+** when the blocking connection's current transaction is concluded. ^The
** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
** call that concludes the blocking connection's transaction.
**
@@ -9535,7 +9684,7 @@ SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
** blocked connection already has a registered unlock-notify callback,
** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
** called with a NULL pointer as its second argument, then any existing
-** unlock-notify callback is canceled. ^The blocked connections
+** unlock-notify callback is canceled. ^The blocked connection's
** unlock-notify callback may also be canceled by closing the blocked
** connection using [sqlite3_close()].
**
@@ -9705,7 +9854,7 @@ SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
** is the number of pages currently in the write-ahead log file,
** including those that were just committed.
**
-** The callback function should normally return [SQLITE_OK]. ^If an error
+** ^The callback function should normally return [SQLITE_OK]. ^If an error
** code is returned, that error will propagate back up through the
** SQLite code base to cause the statement that provoked the callback
** to report an error, though the commit will have still occurred. If the
@@ -9713,13 +9862,26 @@ SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
** that does not correspond to any valid SQLite error code, the results
** are undefined.
**
-** A single database handle may have at most a single write-ahead log callback
-** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
-** previously registered write-ahead log callback. ^The return value is
-** a copy of the third parameter from the previous call, if any, or 0.
-** ^Note that the [sqlite3_wal_autocheckpoint()] interface and the
-** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
-** overwrite any prior [sqlite3_wal_hook()] settings.
+** ^A single database handle may have at most a single write-ahead log
+** callback registered at one time. ^Calling [sqlite3_wal_hook()]
+** replaces the default behavior or previously registered write-ahead
+** log callback.
+**
+** ^The return value is a copy of the third parameter from the
+** previous call, if any, or 0.
+**
+** ^The [sqlite3_wal_autocheckpoint()] interface and the
+** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and
+** will overwrite any prior [sqlite3_wal_hook()] settings.
+**
+** ^If a write-ahead log callback is set using this function then
+** [sqlite3_wal_checkpoint_v2()] or [PRAGMA wal_checkpoint]
+** should be invoked periodically to keep the write-ahead log file
+** from growing without bound.
+**
+** ^Passing a NULL pointer for the callback disables automatic
+** checkpointing entirely. To re-enable the default behavior, call
+** sqlite3_wal_autocheckpoint(db,1000) or use [PRAGMA wal_checkpoint].
*/
SQLITE_API void *sqlite3_wal_hook(
sqlite3*,
@@ -9736,7 +9898,7 @@ SQLITE_API void *sqlite3_wal_hook(
** to automatically [checkpoint]
** after committing a transaction if there are N or
** more frames in the [write-ahead log] file. ^Passing zero or
-** a negative value as the nFrame parameter disables automatic
+** a negative value as the N parameter disables automatic
** checkpoints entirely.
**
** ^The callback registered by this function replaces any existing callback
@@ -9752,9 +9914,10 @@ SQLITE_API void *sqlite3_wal_hook(
**
** ^Every new [database connection] defaults to having the auto-checkpoint
** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
-** pages. The use of this interface
-** is only necessary if the default setting is found to be suboptimal
-** for a particular application.
+** pages.
+**
+** ^The use of this interface is only necessary if the default setting
+** is found to be suboptimal for a particular application.
*/
SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
@@ -9819,6 +9982,11 @@ SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
** addition that it also truncates the log file to zero bytes just prior
** to a successful return.
+**
+** |