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1.0 Compilation Options For SQLite
For most purposes, SQLite can be built just fine using the default compilation options. However, if required, the compile-time options documented below can be used to omit SQLite features (resulting in a smaller compiled library size) or to change the default values of some parameters.
Every effort has been made to ensure that the various combinations of compilation options work harmoniously and produce a working library. Nevertheless, it is strongly recommended that the SQLite test-suite be executed to check for errors before using an SQLite library built with non-standard compilation options.
1.1 Options To Set Default Parameter Values
SQLITE_DEFAULT_AUTOVACUUM=<0 or 1 or 2>
This macro determines if SQLite creates databases with the auto_vacuum flag set by default to OFF (0), FULL (1), or INCREMENTAL (2). The default value is 0 meaning that databases are created with auto-vacuum turned off. In any case the compile-time default may be overridden by the PRAGMA auto_vacuum command.
SQLITE_DEFAULT_CACHE_SIZE=<pages>
This macro sets the default size of the page-cache for each attached database, in pages. This can be overridden by the PRAGMA cache_size command. The default value is 2000.
SQLITE_DEFAULT_FILE_FORMAT=<1 or 4>
The default schema-level file format used by SQLite when creating new database files is set by this macro. The file formats are all very similar. The difference between formats 1 and 4 is that format 4 understands descending indices and has a tighter encoding for boolean values.
SQLite (as of version 3.6.0) can read and write any file format between 1 and 4. But older versions of SQLite might not be able to read formats greater than 1. So that older versions of SQLite will be able to read and write database files created by newer versions of SQLite, the default file format is set to 1 for maximum compatibility.
The file format for a new database can be set at runtime using the PRAGMA legacy_file_format command.
SQLITE_DEFAULT_JOURNAL_SIZE_LIMIT=<bytes>
This option sets the size limit on rollback journal files in persistent journal mode. When this compile-time option is omitted there is no upper bound on the size of the rollback journal file. The journal file size limit can be changed at run-time using the journal_size_limit pragma.
SQLITE_DEFAULT_MEMSTATUS=<1 or 0>
This macro is used to determine whether or not the features enabled and disabled using the SQLITE_CONFIG_MEMSTATUS argument to sqlite3_config() are available by default. The default value is 1 (SQLITE_CONFIG_MEMSTATUS related features enabled).
SQLITE_DEFAULT_PAGE_SIZE=<bytes>
This macro is used to set the default page-size used when a database is created. The value assigned must be a power of 2. The default value is 1024. The compile-time default may be overridden at runtime by the PRAGMA page_size command.
SQLITE_DEFAULT_TEMP_CACHE_SIZE=<pages>
This macro sets the default size of the page-cache for temporary files created by SQLite to store intermediate results, in pages. It does not affect the page-cache for the temp database, where tables created using CREATE TEMP TABLE are stored. The default value is 500.
YYSTACKDEPTH=<max_depth>
This macro sets the maximum depth of the LALR(1) stack used by the SQL parser within SQLite. The default value is 100. A typical application will use less than about 20 levels of the stack. Developers whose applications contain SQL statements that need more than 100 LALR(1) stack entries should seriously consider refactoring their SQL as it is likely to be well beyond the ability of any human to comprehend.
1.2 Options To Set Size Limits
There are compile-time options that will set upper bounds on the sizes of various structures in SQLite. The compile-time options normally set a hard upper bound that can be changed at run-time on individual database connections using the sqlite3_limit() interface.
The compile-time options for setting upper bounds are documented separately. The following is a list of the available settings:
- SQLITE_MAX_ATTACHED
- SQLITE_MAX_COLUMN
- SQLITE_MAX_COMPOUND_SELECT
- SQLITE_MAX_EXPR_DEPTH
- SQLITE_MAX_FUNCTION_ARG
- SQLITE_MAX_LENGTH
- SQLITE_MAX_LIKE_PATTERN_LENGTH
- SQLITE_MAX_PAGE_COUNT
- SQLITE_MAX_SQL_LENGTH
- SQLITE_MAX_VARIABLE_NUMBER
1.3 Options To Control Operating Characteristics
SQLITE_CASE_SENSITIVE_LIKE
If this option is present, then the built-in LIKE operator will be case sensitive. This same effect can be achieved at run-time using the case_sensitive_like pragma.
SQLITE_HAVE_ISNAN
If this option is present, then SQLite will use the isnan() function from the system math library. Without this option (the default behavior) SQLite uses its own internal implementation of isnan(). SQLite uses its own internal isnan() implementation by default because of past problems with system isnan() functions.
SQLITE_OS_OTHER=<0 or 1>
The option causes SQLite to omit its built-in operating system interfaces for Unix, Windows, and OS/2. The resulting library will have no default operating system interface. Applications must use sqlite3_vfs_register() to register an appropriate interface before using SQLite. Applications must also supply implementations for the sqlite3_os_init() and sqlite3_os_end() interfaces. The usual practice is for the supplied sqlite3_os_init() to invoke sqlite3_vfs_register(). SQLite will automatically invoke sqlite3_os_init() when it initializes.
This option is typically used when building SQLite for an embedded platform with a custom operating system.
SQLITE_SECURE_DELETE
This compile-time option changes the default setting of the secure_delete pragma. When this option is not used, secure_delete defaults to off. When this option is present, secure_delete defaults to on.
The secure_delete setting causes deleted content to be overwritten with zeros. There is a small performance penalty for this since additional I/O must occur. On the other hand, secure_delete can prevent sensitive information from lingering in unused parts of the database file after it has allegedly been deleted. See the documentation on the secure_delete pragma for additional information.
SQLITE_THREADSAFE=<0 or 1 or 2>
This option controls whether or not code is included in SQLite to enable it to operate safely in a multithreaded environment. The default is SQLITE_THREADSAFE=1 which is safe for use in a multithreaded environment. When compiled with SQLITE_THREADSAFE=0 all mutexing code is omitted and it is unsafe to use SQLite in a multithreaded program. When compiled with SQLITE_THREADSAFE=2, SQLite can be used in a multithreaded program so long as no two threads attempt to use the same database connection at the same time.
To put it another way, SQLITE_THREADSAFE=1 sets the default threading mode to Serialized. SQLITE_THREADSAFE=2 sets the default threading mode to Multi-threaded. And SQLITE_THREADSAFE=0 sets the threading mode to Single-threaded.
The value of SQLITE_THREADSAFE can be determined at run-time using the sqlite3_threadsafe() interface.
When SQLite has been compiled with SQLITE_THREADSAFE=1 or SQLITE_THREADSAFE=2 then the threading mode can be altered at run-time using the sqlite3_config() interface together with one of these verbs:
The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags to sqlite3_open_v2() can also be used to adjust the threading mode of individual database connections at run-time.
Note that when SQLite is compiled with SQLITE_THREADSAFE=0, the code to make SQLite threadsafe is omitted from the build. When this occurs, it is impossible to change the threading mode at start-time or run-time.
See the threading mode documentation for additional information on aspects of using SQLite in a multithreaded environment.
SQLITE_TEMP_STORE=<0 through 3>
This option controls whether temporary files are stored on disk or in memory. The meanings for various settings of this compile-time option are as follows:
SQLITE_TEMP_STORE Meaning 0 Always use temporary files 1 Use files by default but allow the PRAGMA temp_store command to override 2 Use memory by default but allow the PRAGMA temp_store command to override 3 Always use memory The default setting is 1. Additional information can be found in tempfiles.html.
1.4 Options To Enable Features Normally Turned Off
SQLITE_ENABLE_ATOMIC_WRITE
If this C-preprocessor macro is defined and if the xDeviceCharacteristics method of sqlite3_io_methods object for a database file reports (via one of the SQLITE_IOCAP_ATOMIC bits) that the filesystem supports atomic writes and if a transaction involves a change to only a single page of the database file, then the transaction commits with just a single write request of a single page of the database and no rollback journal is created or written. On filesystems that support atomic writes, this optimization can result in significant speed improvements for small updates. However, few filesystems support this capability and the code paths that check for this capability slow down write performance on systems that lack atomic write capability, so this feature is disabled by default.
SQLITE_ENABLE_COLUMN_METADATA
When this C-preprocessor macro is defined, SQLite includes some additional APIs that provide convenient access to meta-data about tables and queries. The APIs that are enabled by this option are:
SQLITE_ENABLE_FTS3
When this option is defined in the amalgamation, version 3 of the full-text search engine is added to the build automatically.
SQLITE_ENABLE_FTS3_PARENTHESIS
This option modifies the query pattern parser in FTS3 such that it supports operators AND and NOT (in addition to the usual OR and NEAR) and also allows query expressions to contain nested parenthesis.
SQLITE_ENABLE_ICU
This option causes the International Components for Unicode or "ICU" extension to SQLite to be added to the build.
SQLITE_ENABLE_IOTRACE
When both the SQLite core and the Command Line Interface (CLI) are both compiled with this option, then the CLI provides an extra command named ".iotrace" that provides a low-level log of I/O activity. This option is experimental and may be discontinued in a future release.
SQLITE_ENABLE_LOCKING_STYLE
This option enables additional logic in the OS interface layer for Mac OS X. The additional logic attempts to determine the type of the underlying filesystem and choose and alternative locking strategy that works correctly for that filesystem type. Five locking strategies are available:
- POSIX locking style. This is the default locking style and the style used by other (non Mac OS X) Unixes. Locks are obtained and released using the fcntl() system call.
- AFP locking style. This locking style is used for network file systems that use the AFP (Apple Filing Protocol) protocol. Locks are obtained by calling the library function _AFPFSSetLock().
- Flock locking style. This is used for file-systems that do not support POSIX locking style. Locks are obtained and released using the flock() system call.
- Dot-file locking style. This locking style is used when neither flock nor POSIX locking styles are supported by the file system. Database locks are obtained by creating and entry in the file-system at a well-known location relative to the database file (a "dot-file") and relinquished by deleting the same file.
- No locking style. If none of the above can be supported, this locking style is used. No database locking mechanism is used. When this system is used it is not safe for a single database to be accessed by multiple clients.
Additionally, five extra VFS implementations are provided as well as the default. By specifying one of the extra VFS implementations when calling sqlite3_open_v2(), an application may bypass the file-system detection logic and explicitly select one of the above locking styles. The five extra VFS implementations are called "unix-posix", "unix-afp", "unix-flock", "unix-dotfile" and "unix-none".
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().
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 taken. The MEMSYS3 memory allocator uses a hybrid allocation algorithm patterned after dlmalloc(). Only one of SQLITE_ENABLE_MEMSYS3 and SQLITE_ENABLE_MEMSYS5 may be enabled at once.
SQLITE_ENABLE_MEMSYS5
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 taken. The MEMSYS5 module rounds all allocations up to the next power of two and uses a first-fit, buddy-allocator algorithm that provides strong guarantees against fragmentation and breakdown subject to certain operating constraints.
SQLITE_ENABLE_RTREE
This option causes SQLite to include support for the R*Tree index extension.
SQLITE_ENABLE_STAT2
This option adds additional logic to the ANALYZE command and to the query planner that can help SQLite to chose a better query plan under certain situations. The ANALYZE command is enhanced to collect a 10-sample histogram of the data in each index and store that histogram in the sqlite_stat2 table. The query planner will then use the histogram data to help it estimate how many rows will be selected by a range constraint in a WHERE clause.
SQLITE_ENABLE_UPDATE_DELETE_LIMIT
This option enables an optional ORDER BY and LIMIT clause on UPDATE and DELETE statements.
If this option is defined, then it must also be defined when using the 'lemon' tool to generate a parse.c file. Because of this, this option may only be used when the library is built from source, not from the amalgamation or from the collection of pre-packaged C files provided for non-Unix like platforms on the website.
SQLITE_ENABLE_UNLOCK_NOTIFY
This option enables the sqlite3_unlock_notify() interface and its associated functionality. See the documentation titled Using the SQLite Unlock Notification Feature for additional information.
SQLITE_SOUNDEX
This option enables the soundex() SQL function.
YYTRACKMAXSTACKDEPTH
This option causes the LALR(1) parser stack depth to be tracked and reported using the sqlite3_status(SQLITE_STATUS_PARSER_STACK,...) interface. SQLite's LALR(1) parser has a fixed stack depth (determined at compile-time using the YYSTACKDEPTH options). This option can be used to help determine if an application is getting close to exceeding the maximum LALR(1) stack depth.
1.5 Options To Disable Features Normally Turned On
SQLITE_DISABLE_LFS
If this C-preprocessor macro is defined, large file support is disabled.
SQLITE_DISABLE_DIRSYNC
If this C-preprocessor macro is defined, directory syncs are disabled. SQLite typically attempts to sync the parent directory when a file is deleted to ensure the directory entries are updated immediately on disk.
1.6 Options To Omit Features
The following options can used to reduce the size of the compiled library by omitting optional features. This is probably only useful in embedded systems where space is especially tight, as even with all features included the SQLite library is relatively small. Don't forget to tell your compiler to optimize for binary size! (the -Os option if using GCC). Telling your compiler to optimize for size usually has a much larger impact on library footprint than employing any of these compile-time options. You should also verify that debugging options are disabled.
The macros in this section do not require values. The following
compilation switches all have the same effect:
-DSQLITE_OMIT_ALTERTABLE
-DSQLITE_OMIT_ALTERTABLE=1
-DSQLITE_OMIT_ALTERTABLE=0
If any of these options are defined, then the same set of SQLITE_OMIT_* options must also be defined when using the 'lemon' tool to generate the parse.c file and when compiling the 'mkkeywordhash' tool which generates the keywordhash.h file. Because of this, these options may only be used when the library is built from canonical source, not from the amalgamation or from the collection of pre-packaged C files provided for non-Unix like platforms on the website. Any SQLITE_OMIT_* options which can be used directly with the amalgamation are listed below, however, the warnings in the following paragraph should be noted.
Important Note: The SQLITE_OMIT_* options do not work with the amalgamation or with pre-packaged C code files. SQLITE_OMIT_* compile-time options only work correctly when SQLite is built from canonical source files.
Special versions of the SQLite amalgamation that do work with a predetermined set of SQLITE_OMIT_* options can be generated. To do so, make a copy of the Makefile.linux-gcc makefile template in the canonical source code distribution. Change the name of your copy to simply "Makefile". Then edit "Makefile" to set up appropriate compile-time options. Then type:
make clean; make sqlite3.cThe resulting "sqlite3.c" amalgamation code file (and its associated header file "sqlite3.h") can then be moved to a non-unix platform for final compilation using a native compiler.
All of the SQLITE_OMIT_* options are unsupported.
Important Note: The SQLITE_OMIT_* compile-time options are unsupported.
The SQLITE_OMIT_* compile-time options are usually untested and are almost certainly untested in combination. Any or all of these options may be removed from the code in future releases and without warning. For any particular release, some of these options may cause compile-time or run-time failures, particularly when used in combination with other options.
SQLITE_OMIT_ALTERTABLE
When this option is defined, the ALTER TABLE command is not included in the library. Executing an ALTER TABLE statement causes a parse error.
SQLITE_OMIT_ANALYZE
When this option is defined, the ANALYZE command is omitted from the build.
SQLITE_OMIT_ATTACH
When this option is defined, the ATTACH and DETACH commands are omitted from the build.
SQLITE_OMIT_AUTHORIZATION
Defining this option omits the authorization callback feature from the library. The sqlite3_set_authorizer() API function is not present in the library.
SQLITE_OMIT_AUTOINCREMENT
This option is used to omit the AUTOINCREMENT functionality. When this is macro is defined, columns declared as "INTEGER PRIMARY KEY AUTOINCREMENT" behave in the same way as columns declared as "INTEGER PRIMARY KEY" when a NULL is inserted. The sqlite_sequence system table is neither created, nor respected if it already exists.
SQLITE_OMIT_AUTOMATIC_INDEX
This option is used to omit the automatic indexing functionality.
SQLITE_OMIT_AUTOINIT
For backwards compatibility with older versions of SQLite that lack the sqlite3_initialize() interface, the sqlite3_initialize() interface is called automatically upon entry to certain key interfaces such as sqlite3_open(), sqlite3_vfs_register(), and sqlite3_mprintf(). The overhead of invoking sqlite3_initialize() automatically in this way may be omitted by building SQLite with the SQLITE_OMIT_AUTOINIT C-preprocessor macro. When built using SQLITE_OMIT_AUTOINIT, SQLite will not automatically initialize itself and the application is required to invoke sqlite3_initialize() directly prior to beginning use of the SQLite library.
SQLITE_OMIT_AUTOVACUUM
If this option is defined, the library cannot create or write to databases that support auto_vacuum. Executing a PRAGMA auto_vacuum statement is not an error (since unknown PRAGMAs are silently ignored), but does not return a value or modify the auto-vacuum flag in the database file. If a database that supports auto-vacuum is opened by a library compiled with this option, it is automatically opened in read-only mode.
SQLITE_OMIT_BETWEEN_OPTIMIZATION
This option disables the use of indices with WHERE clause terms that employ the BETWEEN operator.
SQLITE_OMIT_BLOB_LITERAL
When this option is defined, it is not possible to specify a blob in an SQL statement using the X'ABCD' syntax.
SQLITE_OMIT_BTREECOUNT
When this option is defined, an optimization that accelerates counting all entries in a table (in other words, an optimization that helps "SELECT count(*) FROM table" run faster) is omitted.
SQLITE_OMIT_BUILTIN_TEST
A standard SQLite build includes a small amount of logic controlled by the sqlite3_test_control() interface that is used to exercise parts of the SQLite core that are difficult to control and measure using the standard API. This option omits that built-in test logic.
SQLITE_OMIT_CAST
This option causes SQLite to omit support for the CAST operator.
SQLITE_OMIT_CHECK
This option causes SQLite to omit support for CHECK constraints. The parser will still accept CHECK constraints in SQL statements, they will just not be enforced.
SQLITE_OMIT_COMPILEOPTION_DIAGS
This option is used to omit the compile-time option diagnostics available in SQLite, including the sqlite3_compileoption_used() and sqlite3_compileoption_get() C/C++ functions, the sqlite_compileoption_used() and sqlite_compileoption_get() SQL functions, and the compile_options pragma.
SQLITE_OMIT_COMPLETE
This option causes the sqlite3_complete() and sqlite3_complete16() interfaces to be omitted.
SQLITE_OMIT_COMPOUND_SELECT
This option is used to omit the compound SELECT functionality. SELECT statements that use the UNION, UNION ALL, INTERSECT or EXCEPT compound SELECT operators will cause a parse error.
SQLITE_OMIT_CONFLICT_CLAUSE
In the future, this option will be used to omit the ON CONFLICT clause from the library.
SQLITE_OMIT_DATETIME_FUNCS
If this option is defined, SQLite's built-in date and time manipulation functions are omitted. Specifically, the SQL functions julianday(), date(), time(), datetime() and strftime() are not available. The default column values CURRENT_TIME, CURRENT_DATE and CURRENT_DATETIME are still available.
SQLITE_OMIT_DECLTYPE
This option causes SQLite to omit support for the sqlite3_column_decltype() and sqlite3_column_decltype16() interfaces.
SQLITE_OMIT_DEPRECATED
This option causes SQLite to omit support for interfaces marked as deprecated. This includes sqlite3_aggregate_count(), sqlite3_expired(), sqlite3_transfer_bindings(), sqlite3_global_recover(), sqlite3_thread_cleanup() and sqlite3_memory_alarm() interfaces.
SQLITE_OMIT_DISKIO
This option omits all support for writing to the disk and forces databases to exist in memory only. This option has not been maintained and probably does not work with newer versions of SQLite.
SQLITE_OMIT_EXPLAIN
Defining this option causes the EXPLAIN command to be omitted from the library. Attempting to execute an EXPLAIN statement will cause a parse error.
SQLITE_OMIT_FLAG_PRAGMAS
This option omits support for a subset of PRAGMA commands that query and set boolean properties.
SQLITE_OMIT_FLOATING_POINT
This option is used to omit floating-point number support from the SQLite library. When specified, specifying a floating point number as a literal (i.e. "1.01") results in a parse error.
In the future, this option may also disable other floating point functionality, for example the sqlite3_result_double(), sqlite3_bind_double(), sqlite3_value_double() and sqlite3_column_double() API functions.
SQLITE_OMIT_FOREIGN_KEY
If this option is defined, then foreign key constraint syntax is not recognized.
SQLITE_OMIT_GET_TABLE
This option causes support for sqlite3_get_table() and sqlite3_free_table() to be omitted.
SQLITE_OMIT_INCRBLOB
This option causes support for incremental BLOB I/O to be omitted.
SQLITE_OMIT_INTEGRITY_CHECK
This option omits support for the integrity_check pragma.
SQLITE_OMIT_LIKE_OPTIMIZATION
This option disables the ability of SQLite to use indices to help resolve LIKE and GLOB operators in a WHERE clause.
SQLITE_OMIT_LOAD_EXTENSION
This option omits the entire extension loading mechanism from SQLite, including sqlite3_enable_load_extension() and sqlite3_load_extension() interfaces.
SQLITE_OMIT_LOCALTIME
This option omits the "localtime" modifier from the date and time functions. This option is sometimes useful when trying to compile the date and time functions on a platform that does not support the concept of local time.
SQLITE_OMIT_LOOKASIDE
This option omits the lookaside memory allocator.
SQLITE_OMIT_MEMORYDB
When this is defined, the library does not respect the special database name ":memory:" (normally used to create an in-memory database). If ":memory:" is passed to sqlite3_open(), sqlite3_open16(), or sqlite3_open_v2(), a file with this name will be opened or created.
SQLITE_OMIT_OR_OPTIMIZATION
This option disables the ability of SQLite to use an index together with terms of a WHERE clause connected by the OR operator.
SQLITE_OMIT_PAGER_PRAGMAS
Defining this option omits pragmas related to the pager subsystem from the build.
SQLITE_OMIT_PRAGMA
This option is used to omit the PRAGMA command from the library. Note that it is useful to define the macros that omit specific pragmas in addition to this, as they may also remove supporting code in other sub-systems. This macro removes the PRAGMA command only.
SQLITE_OMIT_PROGRESS_CALLBACK
This option may be defined to omit the capability to issue "progress" callbacks during long-running SQL statements. The sqlite3_progress_handler() API function is not present in the library.
SQLITE_OMIT_QUICKBALANCE
This option omits an alternative, faster B-Tree balancing routine. Using this option makes SQLite slightly smaller at the expense of making it run slightly slower.
SQLITE_OMIT_REINDEX
When this option is defined, the REINDEX command is not included in the library. Executing a REINDEX statement causes a parse error.
SQLITE_OMIT_SCHEMA_PRAGMAS
Defining this option omits pragmas for querying the database schema from the build.
SQLITE_OMIT_SCHEMA_VERSION_PRAGMAS
Defining this option omits pragmas for querying and modifying the database schema version and user version from the build. Specifically, the schema_version and user_version PRAGMAs are omitted.
SQLITE_OMIT_SHARED_CACHE
This option builds SQLite without support for shared-cache mode. The sqlite3_enable_shared_cache() is omitted along with a fair amount of logic within the B-Tree subsystem associated with shared cache management.
SQLITE_OMIT_SUBQUERY
If defined, support for sub-selects and the IN() operator are omitted.
SQLITE_OMIT_TCL_VARIABLE
If this macro is defined, then the special "$
" syntax used to automatically bind SQL variables to TCL variables is omitted.
SQLITE_OMIT_TEMPDB
This option omits support for TEMP or TEMPORARY tables.
SQLITE_OMIT_TRACE
This option omits support for the sqlite3_profile() and sqlite3_trace() interfaces and their associated logic.
SQLITE_OMIT_TRIGGER
Defining this option omits support for TRIGGER objects. Neither the CREATE TRIGGER or DROP TRIGGER commands are available in this case, and attempting to execute either will result in a parse error. This option also disables enforcement of foreign key constraints, since the code that implements triggers and which is omitted by this option is also used to implement foreign key actions.
SQLITE_OMIT_TRUNCATE_OPTIMIZATION
A default build of SQLite, if a DELETE statement has no WHERE clause and operates on a table with no triggers, an optimization occurs that causes the DELETE to occur by dropping and recreating the table. Dropping and recreating a table is usually much faster than deleting the table content row by row. This is the "truncate optimization".
SQLITE_OMIT_UTF16
This macro is used to omit support for UTF16 text encoding. When this is defined all API functions that return or accept UTF16 encoded text are unavailable. These functions can be identified by the fact that they end with '16', for example sqlite3_prepare16(), sqlite3_column_text16() and sqlite3_bind_text16().
SQLITE_OMIT_VACUUM
When this option is defined, the VACUUM command is not included in the library. Executing a VACUUM statement causes a parse error.
SQLITE_OMIT_VIEW
Defining this option omits support for VIEW objects. Neither the CREATE VIEW nor the DROP VIEW commands are available in this case, and attempting to execute either will result in a parse error.
WARNING: If this macro is defined, it will not be possible to open a database for which the schema contains VIEW objects.
SQLITE_OMIT_VIRTUALTABLE
This option omits support for the Virtual Table mechanism in SQLite.
SQLITE_OMIT_WAL
This option omits the "write-ahead log" (a.k.a. "WAL") capability.
SQLITE_OMIT_WSD
This options builds a version of the SQLite library that contains no Writable Static Data (WSD). WSD is global variables and/or static variables. Some platforms do not support WSD, and this option is necessary in order for SQLite to work those platforms.
Unlike other OMIT options which make the SQLite library smaller, this option actually increases the size of SQLite and makes it run a little slower. Only use this option if SQLite is being built for an embedded target that does not support WSD.
SQLITE_OMIT_XFER_OPT
This option omits support for optimizations that help statements of the form "INSERT INTO ... SELECT ..." run faster.
SQLITE_ZERO_MALLOC
This option omits both the default memory allocator and the debugging memory allocator from the build and substitutes a stub memory allocator that always fails. SQLite will not run with this stub memory allocator since it will be unable to allocate memory. But this stub can be replaced at start-time using sqlite3_config(SQLITE_CONFIG_MALLOC,...) or sqlite3_config(SQLITE_CONFIG_HEAP,...). So the net effect of this compile-time option is that it allows SQLite to be compiled and linked against a system library that does not support malloc(), free(), and/or realloc().
1.7 Analysis and Debugging Options
SQLITE_DEBUG
The SQLite source code contains literally thousands of assert() statements used to verify internal assumptions and subroutine preconditions and postconditions. These assert() statements are normally turned off (they generate no code) since turning them on makes SQLite run approximately three times slower. But for testing and analysis, it is useful to turn the assert() statements on. The SQLITE_DEBUG compile-time option does this. SQLITE_DEBUG also turns on some other debugging features.
SQLITE_MEMDEBUG
The SQLITE_MEMDEBUG option causes an instrumented debugging memory allocator to be used as the default memory allocator within SQLite. The instrumented memory allocator checks for misuse of dynamically allocated memory. Examples of misuse include using memory after it is freed, writing off the ends of a memory allocation, freeing memory not previously obtained from the memory allocator, or failing to initialize newly allocated memory.
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