SQLite version 3.8.1 is a regularly scheduled maintenance release. Upgrading from the previous release is optional, though you should upgrade if you are using partial indices as there was a bug related to partial indices in the previous release that could result in an incorrect answer for count(*) queries.
The next generation query planner that was premiered in the previous release continues to work well. The new query planner has been tweaked slightly in the current release to help it make better decisions in some cases, but is largely unchanged. Two new SQL functions, likelihood() and unlikely(), have been added to allow developers to give hints to the query planner without forcing the query planner into a particular decision.
Version 3.8.1 is the first SQLite release to take into account the estimated size of table and index rows when choosing a query plan. Row size estimates are based on the declared datatypes of columns. For example, a column of type VARCHAR(1000) is assumed to use much more space than a column of type INT. The datatype-based row size estimate can be overridden by appending a term of the form "sz=NNN" (where NNN is the average row size in bytes) to the end of the sqlite_stat1.stat record for a table or index. Currently, row sizes are only used to help the query planner choose between a table or one of its indices when doing a table scan or a count(*) operation, though future releases are likely to use the estimated row size in other contexts as well. The new PRAGMA stats statement can be used to view row size estimates.
Version 3.8.1 adds the SQLITE_ENABLE_STAT4 compile-time option. STAT4 is very similar to STAT3 in that it uses samples from indices to try to guess how many rows of the index will be satisfy by WHERE clause constraints. The difference is that STAT4 samples all columns of the index whereas the older STAT3 only sampled the left-most column. Users of STAT3 are encouraged to upgrade to STAT4. Application developers should use STAT3 and STAT4 with caution since both options, by design, violate the query planner stability guarantee, making it more difficult to ensure uniform performance is widely-deployed and mass-produced embedded applications.
SQLite version 188.8.131.52 contains a one-line fix to a bug in the new optimization that tries to omit unused LEFT JOINs from a query.
SQLite version 184.108.40.206 fixes some obscure bugs that were uncovered by users in the 3.8.0 release. Changes from 3.8.0 are minimal.
Do not fear the zero!
SQLite version 3.8.0 might easily have been called "3.7.18" instead. However, this release features the cutover of the next generation query planner or NGQP, and there is a small chance of breaking legacy programs that rely on undefined behavior in previous SQLite releases, and so the minor version number was incremented for that reason. But the risks are low and there is a query planner checklist is available to application developers to aid in avoiding problems.
SQLite version 3.8.0 is actually one of the most heavily tested SQLite releases ever. Thousands and thousands of beta copies have be downloaded, and presumably tested, and there have been no problem reports.
SQLite version 3.7.17 is a regularly schedule maintenance release. Visit the change log for a full explanation of the changes in this release.
There are many bug fixes in version 3.7.17. But this does not indicate that 3.7.16 was a problematic release. All of the bugs in 3.7.17 are obscure and are unlikely to impact any particular application. And most of the bugs that are fixed in 3.7.17 predate 3.7.16 and have been in the code for years without ever before being noticed. Nevertheless, due to the large number of fixes, all users are encouraged to upgrade when possible.
SQLite version 220.127.116.11 fixes a long-standing flaw in the Windows OS interface that can result in database corruption under a rare race condition. See http://www.sqlite.org/src/info/7ff3120e4f for a full description of the problem.
As far as we know, this bug has never been seen in the wild. The problem was discovered by the SQLite developers while writing stress tests for a separate component of SQLite. Those stress tests have not yet found any problems with the component they were intended to verify, but they did find the bug which is the subject of this patch release.
Other than updates to version numbers, the only difference between this release and 18.104.22.168 is a two-character change in a single identifier, which is contained in the windows-specific OS interface logic. There are no changes in this release (other than version numbers) for platforms other than Windows.
SQLite version 22.214.171.124 is a bug fix release that fixes a few problems that were present in the previous releases.
The primary motivation for version 126.96.36.199 is to fix a bug in the query optimizer that was introduced as part of version 3.7.15. The query optimizer was being a little overzealous in optimizing out some ORDER BY clauses, which resulted in sorting being omitted on occasions where sorting is required to get the correct answer. See ticket a179fe7465 for details.
In addition to the ORDER BY fix, several other patches to fix obscure (and mostly harmless) bugs and to fix spelling errors in source code comments are also included in this release.
SQLite version 3.7.16 is a regularly scheduled release of SQLite. This release contains several language enhancements and improvements to the query optimizer. A list of the major enhancements and optimizations can be see on the change log.
There was one important bug fix (see Ticket fc7bd6358f) that addresses an incorrect query result that could have occurred in a three-way join where the join constraints compared INTEGER columns to TEXT columns. This issue had been in the code for time out of mind and had never before been reported, so we surmise that it is very obscure. Nevertheless, all users are advised to upgrade to avoid any future problems associated with this issue.
SQLite version 188.8.131.52 is a patch release that fixes a single bug that was introduced in version version 3.7.15. The fix is a 4-character edit to a single line of code. Other than this 4-character change and the update of the version number, nothing has changed from version 184.108.40.206.
SQLite version 220.127.116.11 is a patch release that fixes a single bug that was introduced in version version 3.7.15. The fix involved changing two lines of code and adding a single assert(). This release also includes some new test cases to prevent a regression of the bug, and the version number is increased, of course. But otherwise, nothing has changed from version 3.7.15.
SQLite version 3.7.15 is a regularly schedule release of SQLite. This release contains several improvements to the query planner and optimizer and one important bug fix. This is the first release to officially support Windows 8 Phone.
The important bug fix is a problem that can lead to segfaults when using shared cache mode on a schema that contains a COLLATE operator within a CHECK constraint or within a view. Collating functions are associated with individual database connections. But a pointer to the collating function was also being cached within expressions. If an expression was part of the schema and contained a cached collating function, it would point to the collating function in the database connection that originally parsed the schema. If that database connection closed while other database connections using the same shared cache continued to operate, they other database connections would try to use the deallocated collating function in the database connection that closed. The fix in version 3.7.15 was to not cache collating function pointers in the expression structure but instead look them up each time a new statement is prepared.
This release also contains some important enhancements to the query planner which should (we hope) make some queries run faster. The enhancements include:
When doing a full-table scan, try to use an index instead of the original table, under the theory that indices contain less information and are thus smaller and hence require less disk I/O to scan.
Do a better job of recognizing when an ORDER BY clause can be implemented using indices - especially in cases where the ORDER BY clause contains terms from two or more tables in a join.
SQLite version 18.104.22.168 is a patch release. Changes from the baseline version 3.7.14 are minimal and are restricted to fixing three bugs.
One of the fixed bugs is a long-standing issue with the TCL interface. Another is an external compiler bug that SQLite merely works around and that only comes up if you are using the VisualStudio-2012 compiler to generate WinRT applications on ARM with optimizations enabled. The third problem is an SQLite core bug, introduced in version 3.7.14, that can cause a segfault if a query contains a LEFT JOIN that contains an OR in the ON clause.
SQLite version 3.7.14 is a regularly scheduled maintenance release of SQLite. The previous release continues to work well. Upgrading is optional.
Version 3.7.14 drops native support for OS/2. We are not aware of any active projects that were using SQLite on OS/2 and since the SQLite developers had no way of testing on OS/2 it seemed like it was time to simply remove the OS/2 code from the SQLite tree. If there are OS/2 projects out there that still need SQLite support, they can continue to maintain their own private VFS which can be linked to SQLite at start-time using the sqlite3_vfs_register() interface.
The sqlite3_close_v2() interface has been added. The sqlite3_close_v2() interface differs from sqlite3_close() in that it is designed to work better for host language that use a garbage collector. With the older sqlite3_close() interface, the associated prepared statements and sqlite3_backup objects must be destroyed before the database connection. With the newer sqlite3_close_v2() interface, the objects can be destroyed in any order.
This release also includes performance improvements to the sort algorithm that is used to implement ORDER BY and CREATE INDEX. And the query planner has been enhanced to better use covering indices on queries that use OR terms in the WHERE clause.
SQLite version 3.7.13 adds support for WinRT and metro style applications for Microsoft Windows 8. The 3.7.13 release is coming sooner than is usual after the previous release in order to get this new capability into the hands of developers. To use SQLite in a metro style application, compile with the -DSQLITE_OS_WINRT flag. Because of the increased application security and safety requirements of WinRT, all database filenames should be full pathnames. Note that SQLite is not capable of accessing databases outside the installation directory and application data directory. This restriction is another security and safety feature of WinRT. Apart from these restrictions, SQLite should work exactly the same on WinRT as it does on every other system.
Also in this release: when a database is opened using URI filenames and the mode=memory query parameter then the database is an in-memory database, just as if it had been named ":memory:". But, if shared cache mode is enabled, then all other database connections that specify the same URI filename will connect to the same in-memory database. This allows two or more database connections (in the same process) to share the same in-memory database.
This release also includes some corner-case performance optimizations that are obscure yet significant to an important subset of SQLite users. Getting these performance optimizations into circulation quickly is yet another reason for making this release so soon following the previous.
The next release of SQLite is scheduled to occur after the usual 2 or 3 month interval.
SQLite version 22.214.171.124 is a patch release for version 3.7.12 that fixes a bug that was introduced in version 3.7.12 and that can cause a segfault for certain obscure nested aggregate queries. There are very few changes in 126.96.36.199, and upgrading is only needed for applications that do nested aggregate queries.
SQLite version 3.7.12 is a regularly scheduled maintenance release. This release contains several new optimizations and bug fixes and upgrading is recommended. See the change summary for details.
SQLite version 3.7.11 is a regularly scheduled maintenance release which was rushed out early due to a bug in the query optimizer introduced in the previous release. The bug is obscure - it changes a LEFT JOIN into an INNER JOIN in some cases when there is a 3-way join and OR terms in the WHERE clause. But it was considered serious enough to rush out a fix. Apart from this one problem, SQLite version 3.7.10 has not given any trouble. Upgrading to version 3.7.11 from versions 188.8.131.52, 3.7.7, 184.108.40.206, 3.7.8, or 3.7.9 is optional. Upgrading from other releases, including the previous release 3.7.10, is recommended.
Other enhancements found in this release are enumerated in the change log.
SQLite version 3.7.10 is a regularly scheduled maintenance release. Upgrading from version 220.127.116.11, 3.7.7, 18.104.22.168, 3.7.8, or 3.7.9 is optional. Upgrading from other releases is recommended.
The SQLITE_CONFIG_PCACHE mechanism has been replaced with SQLITE_CONFIG_PCACHE2. If you do not know what this mechanism is (it is an extreme corner-case and is seldom used) then this change will not effect you in the least.
The default schema format number for new database files has changed from 1 to 4. SQLite has been able to generate and read database files using schema format 4 for six years. But up unto now, the default schema format has been 1 so that older versions of SQLite could read and write databases generated by newer versions of SQLite. But those older versions of SQLite have become so scarce now that it seems reasonable to make the new format the default.
SQLite is changing some of the assumptions it makes above the behavior of disk drives and flash memory devices during a sudden power loss. This change is completely transparent to applications. Read about the powersafe overwrite property for additional information.
Lots of new interfaces have been added in this release:
- PRAGMA shrink_memory
The PRAGMA cache_size statement has been enhanced. Formerly, you would use this statement to tell SQLite how many pages of the database files it should hold in its cache at once. The total memory requirement would depend on the database page size. Now, if you give PRAGMA cache_size a negative value -N, it will allocate roughly N kibibytes of memory to cache, divided up according to page size. This enhancement allows programs to more easily control their memory usage.
There have been several obscure bug fixes. One noteworthy bug, ticket ff5be73dee, could in theory result in a corrupt database file if a power loss occurred at just the wrong moment on an unusually cantankerous disk drive. But that is mostly a theoretical concern and is very unlikely to happen in practice. The bug was found during laboratory testing and has never been observed to occur in the wild.
SQLite version 3.7.9 is a regularly scheduled maintenance release. Upgrading from version 22.214.171.124, 3.7.7, 126.96.36.199, and 3.7.8 is optional. Upgrading from other versions is recommended.
The SQLITE_ENABLE_STAT2 compile-time option is now a no-op. The enhanced query-planner functionality formerly available using SQLITE_ENABLE_STAT2 is now available through SQLITE_ENABLE_STAT3. The enhanced query planning is still disabled by default. However, future releases of SQLite might convert STAT3 from an enable-option to a disable-option so that it is available by default and is only omitted upon request.
The FTS4 full-text search engine has been enhanced such that tokens in the search string that begin with "^" must be the first token in their respective columns in order to match. Formerly, "^" characters in the search string were simply ignored. Hence, if a legacy application was including "^" characters in FTS4 search strings, thinking that they would always be ignored, then those legacy applications might break with this update. The fix is simply remove the "^" characters from the search string.
See the change summary for additional changes associated with this release.
SQLite version 3.7.8 is a quarterly maintenance release. Upgrading from versions 188.8.131.52, 3.7.7, or 184.108.40.206 is optional. Upgrading from other versions is recommended.
This release features a new "external merge sort" algorithm used to implement ORDER BY and GROUP BY and also to presort the content of an index for CREATE INDEX. The new algorithm does approximately the same number of comparisons and I/Os as before, but the I/Os are much more sequential and so runtimes are greatly reduced when the size of the set being sorted is larger than the filesystem cache. The performance improvement can be dramatic - orders of magnitude faster for large CREATE INDEX commands. On the other hand, the code is slightly slower (1% or 2%) for a small CREATE INDEX. Since CREATE INDEX is not an operation that commonly occurs on a speed-critical path, we feel that this tradeoff is a good one. The slight slowdown for small CREATE INDEX statements might be recovered in a future release. ORDER BY and GROUP BY operations should now be faster for all cases, large and small.
The query planner has been enhanced to do a better job of handling the DISTINCT keyword on SELECT statements.
There has been a lot of work on the default VFSes. The unix VFS has been enhanced to include more overrideable system calls - a feature requested by Chromium to make it easier to build SQLite into a sandbox. The windows VFS has been enhanced to be more resistant to interference from anti-virus software.
Every version of SQLite is better tested than the previous, and 3.7.8 is no exception to this rule. Version 3.7.8 has been used internally by the SQLite team for mission critical functions and has performed flawlessly. And, of course, it passes our rigorous testing procedures with no problems detected. Version 3.7.8 is recommended for all new development.
SQLite version 220.127.116.11 adds a one-line bug fix to 3.7.7 to fix a problem causing PRAGMA case_sensitive_like statements compiled using the legacy sqlite3_prepare() interface to fail with an SQLITE_SCHEMA error. Because sqlite3_exec() uses sqlite3_prepare() internally, the problem also affects sqlite3_exec().
Upgrading from 3.7.7 is only required for applications that use "PRAGMA case_sensitive_like" and the sqlite3_prepare() (or sqlite3_exec()) interface.
SQLite version 3.7.7 is a regularly scheduled bi-monthly maintenance release. Upgrading from version 18.104.22.168 is optional. Upgrading from all prior releases is recommended.
This release adds support for naming database files using URI filenames. URI filenames are disabled by default (for backwards compatibility) but applications are encouraged to enable them since incompatibilities are likely to be exceedingly rare and the feature is useful. See the URI filename documentation for details.
Most of the other enhancements in this release involve virtual tables. The virtual table interface has been enhanced to support SAVEPOINT and ON CONFLICT clause processing, and the built-in RTREE and FTS3/FTS4 have been augmented to take advantage of the new capability. This means, for example, that it is now possible to use the REPLACE command on FTS3/FTS4 and RTREE tables.
The FTS4 full-text index extension has been enhanced to support the FTS4 prefix option and the FTS4 order option. These two enhancements are provided in support of search-as-you-type interfaces where search results begin to appear after the first keystroke in the "search" box and are refined with each subsequent keystroke. The way this is done is to do a separate full-text search after each key stroke, and add the "*" wildcard at the end of the word currently being typed. So, for example, if the text typed so far is "fast da" and the next character typed is "t", then the application does a full-text search of the pattern "fast dat*" and displays the results. Such capability has always existed. What is new is that the FTS4 prefix option allows the search to be very fast (a matter of milliseconds) even for difficult cases such as "t*" or "th*".
There has been a fair amount of work done on the FTS4 module for this release. But the core SQLite code has changed little and the previous release has not given any problems, so we expect this to be a very stable release.
SQLite version 22.214.171.124 is a patch release that fixes a single bug associated with WAL mode. The bug has been in SQLite ever since WAL was added, but the problem is very obscure and so nobody has noticed before now. Nevertheless, all users are encouraged to upgrade to version 126.96.36.199 or later.
The bug is this: If the cache_size is set very small (less than 10) and SQLite comes under memory pressure and if a multi-statement transaction is started in which the last statement prior to COMMIT is a SELECT statement and if a checkpoint occurs right after the transaction commit, then it might happen that the transaction will be silently rolled back instead of being committed.
The default setting for cache_size is 2000. So in most situations, this bug will never appear. But sometimes programmers set cache_size to very small values on gadgets and other low-memory devices in order to save memory space. Such applications are vulnerable. Note that this bug does not cause database corruption. It is as if ROLLBACK were being run instead of COMMIT in some cases.
Transactions commit in WAL mode by adding a record onto the end of the WAL (the write-ahead log) that contains a "commit" flag. So to commit a transaction, SQLite takes all the pages that have changed during that transaction, appends them to the WAL, and sets the commit flag on the last page. Now, if SQLite comes under memory pressure, it might try to free up memory space by writing changed pages to the WAL prior to the commit. We call this "spilling" the cache to WAL. There is nothing wrong with spilling cache to WAL. But if the memory pressure is severe, it might be that by the time COMMIT is run, all changed pages for the transaction have already been spilled to WAL and there are no pages left to be written to WAL. And with no unwritten pages, there was nothing to put the commit flag on. And without a commit flag, the transaction would end up being rolled back.
The fix to this problem was that if all changed pages has already been written to the WAL when the commit was started, then page 1 of the database will be written to the WAL again, so that there will always be a page available on which to set the commit flag.
SQLite version 188.8.131.52 adds a one-line bug fix to 184.108.40.206 that enables pthreads to work correctly on NetBSD. The problem was a faulty function signature for the open system call. The problem does not appear to have any adverse impact on any system other than NetBSD.
Upgrading from version 220.127.116.11 is only needed on NetBSD.
SQLite version 18.104.22.168 fixes a single bug in 3.7.6 that can cause a segfault if SQLITE_FCNTL_SIZE_HINT is used on a unix build that has SQLITE_ENABLE_LOCKING_MODE set to 0 and is compiled with HAVE_POSIX_FALLOCATE.
Upgrading from 3.7.6 is only needed for users effected by the configuration-specific bug described above. There are no other changes to the code.
SQLite version 3.7.6 is a regularly scheduled bi-monthly maintenance release of SQLite. Upgrading from version 3.7.5 is optional. Upgrading releases prior to 3.7.5 is recommended.
SQLite version 3.7.5 is a regularly scheduled bi-monthly maintenance release of SQLite. Due to the discovery and fix of an obscure bug that could cause database corruption, upgrading from all prior releases of SQLite is recommended. This bug was found during code review and has not been observed in the wild.
This release adds new opcodes for the sqlite3_db_status() interface that allow more precise measurement of how the lookaside memory allocator is performing, which can be useful for tuning in applications with very tight memory constraints.
Testing with Valgrind shows that this release of SQLite is about 1% or 2% faster than the previous release for most operations.
A fork of the popular ADO.NET adaptor for SQLite known as System.Data.SQLite is now available on http://System.Data.SQLite.org/. The originator of System.Data.SQLite, Robert Simpson, is aware of this fork, has expressed his approval, and has commit privileges on the new Fossil repository. The SQLite development team intends to maintain System.Data.SQLite moving forward.
SQLite version 3.7.4 is a regularly scheduled bi-monthly maintenance release of SQLite. Upgrading from version 3.7.2 and version 3.7.3 is optional. Upgrading from all other SQLite releases is recommended.
This release features full-text search enhancements. The older FTS3 virtual table is still fully supported, and should also run faster. In addition, the new FTS4 virtual table is added. FTS4 follows the same syntax as FTS3 but holds additional metadata which facilitates some performance improvements and more advanced matchinfo() output. Look for further full-text search enhancements in subsequent releases.
Also in this release, the EXPLAIN QUERY PLAN output has been enhanced and new documentation is provided so that application developers can more easily understand how SQLite is performing their queries.
- Linux x86 & x86_64
- MacOS 10.5 & 10.6
- MacOS 10.2 PowerPC
- WinXP and Win7
- Android 2.2
- OpenBSD 4.7
The previous release of SQLite (version 3.7.3) has proven to be very robust. The only serious issue discovered was ticket 80ba201079 that describes an incorrect query result that can occur under very unusual circumstances. The ticket description contains details of the problem. Suffice it to say here that the problem is very obscure and is unlikely to effect most applications and so upgrading is optional. The problem is fixed, of course, in this release.
SQLite version 3.7.3 is a regularly scheduled bi-monthly maintenance release of SQLite. Upgrading from version 3.7.2 is optional. Upgrading from all other releases is recommended.
This release adds two new interfaces (really just variations on existing interfaces). The sqlite3_create_function_v2() interface adds a destructor for the application-data pointer. The new sqlite3_soft_heap_limit64() interface allows the soft heap limit to be set to a value greater than 231.
The 3.7.3 release also includes some performance enhancements, including query planner improvements, documentation updates, and fixes to some very obscure bugs.
SQLite version 3.7.2 fixes a long-standing bug that can cause the database free-page list to go corrupt if incremental_vacuum is used multiple times to partially reduce the size of a database file that contains many hundreds of unused database pages. The original bug reports together with links to the patch that fixes it can be seen here.
This bug has been in the code for at least a year and possibly longer. The bug has nothing to do with the versions 3.7.1 or 3.7.0 or any other recent release. The fact that the bug was discovered (and fixed) within hours of the 3.7.1 release is purely a coincidence.
The bug is impossible to hit without using incremental_vacuum and is very difficult to hit even with incremental_vacuum. And the kind of corruption that the bug causes can usually be fixed simply by running VACUUM. Nevertheless, because the bug can result in database corruption, it is recommended that all SQLite users upgrade to version 3.7.2 or later.
SQLite version 3.7.1 is a stabilization release for the 3.7.x series. Other than the filesize-in-header bug that was fixed in version 22.214.171.124, no major problems have been seen in 3.7.0. Some minor corner-case performance regressions have been fixed. A typo in the OS/2 interface has been repaired.
A biggest part of the 3.7.1 release is a cleanup and refactoring of the pager module within SQLite. This refactoring should have no application-visible effects. The purpose was to reorganize the code in ways that make it easier to prove correctness.
The 3.7.1 release adds new experimental methods for obtained more detailed memory usage information and for controlling database file fragmentation. And the query planner now does a better job of optimizing the LIKE and GLOB operators.
This release increases the maximum size of database pages from 32KiB to 64KiB. A database with 64KiB pages will not be readable or writable by older versions of SQLite. Note that further increases in page size are not feasible since the file format uses 16-bit offsets to structures within each page.
SQLite version 126.96.36.199 is a patch release to fix a bug in the new filesize-in-header feature of the SQLite file format that could cause database corruption if the same database file is written alternately with version 3.7.0 and version 188.8.131.52 or earlier. A performance regression was also fixed in this release.
SQLite version 3.7.0 is a major release of SQLite that features a new transaction control mechanism using a write-ahead log or WAL. The traditional rollback-journal is still used as the default so there should be no visible change for legacy programs. But newer programs can take advantage of improved performance and concurrency by enabling the WAL journaling mode.
SQLite version 3.7.0 also contains some query planner enhancements and a few obscure bug fixes, but the only really big change is the addition of WAL mode.
SQLite version 184.108.40.206 is a patch release to fix a bug in the offsets() function of FTS3 at the request of the Mozilla.
SQLite version 3.6.23 is a regular bimonthly release of SQLite. Upgrading from the prior release is purely optional.
This release contains new pragmas: the secure_delete pragma, and the compile_options pragma. There are a new SQL functions: sqlite_compileoption_used() and sqlite_compileoption_get(). New C/C++ interfaces: sqlite3_compileoption_used(), sqlite3_compileoption_get(), SQLITE_CONFIG_LOG, and sqlite3_log().
The ".genfkey" command in the Command Line Interface has been removed. SQLite has supported standard SQL foreign key constraints since version 3.6.19 and so the ".genfkey" command was seen as an anachronism.
SQLite version 3.6.22 is a bug-fix release. Two bugs have been fixed that might cause incorrect query results.
Both bugs are obscure, but because they could arise in an application after deployment, it is recommended that all applications upgrade SQLite to version 3.6.22.
- Ticket 31338dca7e describes a problem with queries that have a WHERE clause of the form (x AND y) OR z where x and z come from one table of a join and y comes from a different table.
- Ticket eb5548a849 describes a problem where the use of the CAST operator in the WHERE clause can lead to incorrect results if the column being cast to a new datatype is also used in the same WHERE clause without being cast.
This release also includes other minor bug fixes and performance enhancements, especially in the FTS3 extension.
SQLite version 3.6.21 focuses on performance optimization. For a certain set of traces, this version uses 12% fewer CPU instructions than the previous release (as measured by Valgrind). In addition, the FTS3 extension has been through an extensive cleanup and rework and the sqlite3_trace() interface has been modified to insert bound parameter values into its output.
SQLite version 3.6.20 is a general maintenance release. The query planner has been enhanced to work better with bound parameters in LIKE and GLOB operators and in range constraints and various minor bugs have been fixed. Upgrading from 3.6.19 is optional.
SQLite version 3.6.19 adds native support for foreign key constraints, including deferred constraints and cascading deletes. Enforcement of foreign keys is disabled by default for backwards compatibility and must be turned on using the foreign_keys pragma.
Version 3.6.19 also adds support for the IS and IS NOT operators. Formerly, SQLite (as most other SQL database engines) supported IS NULL and IS NOT NULL. The IS and IS NOT operators are generalizations that allow the right-hand side to be an arbitrary expression. IS and IS NOT work the same as == (equals) and != (not equals) except that with IS and IS NOT the NULL values compare equal to one another.
Beginning with this release, the SQLite source code is tracked and managed using the Fossil distributed configuration management system. SQLite was previously versioned using CVS. The entire CVS history has been imported into Fossil. The older CVS repository remains on the website but is read-only.
There are two major enhancements in SQLite version 3.6.18. The first is a series or refinements to the query planner that help SQLite to choose better plans for joins where in the past it was selecting suboptimal query plans. The SQLITE_ENABLE_STAT2 compile-time option has been added to cause SQLite to collect histogram data on indices when the ANALYZE command is run. The use of histograms improve the query planning performance even more.
The second major enhancement is that SQLite now support recursive triggers. The older non-recursive behavior of triggers is still the default behavior. Recursive triggers are activated using the recursive_triggers pragma. In addition to allowing triggers to call themselves (either directly or indirectly) the new capability also fires DELETE triggers on rows that are removed from a table as a result of REPLACE conflict resolution processing.
Non-recursive triggers are still the default behavior since this is least likely to cause problems for existing applications. However, we anticipate that triggers will become recursive by default beginning with release 3.7.0. At that point, applications that want to continue using the older non-recursive trigger behavior will need to use the recursive_triggers pragma to disable recursive triggers.
This version of SQLite also contains bug fixes, though none of the bugs are serious and all are obscure, so upgrading is optional.
The SQLite core continues to have 100% branch test coverage and so despite the many changes in this release, the developers believe that this version of SQLite is stable and ready for production use.
This is a monthly maintenance release with a focus of bug fixes, performance improvements, and increased test coverage. This is the first release of SQLite since 100% branch test coverage was achieved on the SQLite core.
In addition, a new interface sqlite3_strnicmp() is provided for the convenience of extension writers.
None of the bugs fixed in this release are serious. All bugs are obscure. Upgrading is optional.
A subset of the TH3 test suite was measured by gcov to provide 100% branch test coverage over the SQLite core (exclusive of the VFS backend and of extensions such as FTS3 and RTREE) when compiled for SuSE 10.1 Linux on x86. The SQLite developers pledge to maintain branch test coverage at 100% in all future releases. Ongoing work will strive for 100% branch test coverage on the operating-system backends and extensions as well.
SQLite version 3.6.16 is another general maintenance release containing performance and robustness enhancements. A single notable bug was fixed (ticket #3929). This bug cause cause INSERT or UPDATE statements to fail on indexed tables that have AFTER triggers that modify the same table and index.
SQLite version 3.6.15 is a general maintenance release containing performance and robustness enhancements and fixes for various obscure bugs.
SQLite version 220.127.116.11 fixes an obscure bug in the code generator (ticket #3879) section of SQLite which can potentially cause incorrect query results. The changes from the prior release consist of only this one bug fix, check-in  and a change to the version number text.
The bug was introduced in version 3.6.14. It is recommended that users of version 3.6.14 and 18.104.22.168 upgrade to this release. Applications are unlikely to hit this bug, but since it is difficult to predict which applications might hit it and which might not, we recommend that all users of 3.6.14 and 22.214.171.124 upgrade to this release.
SQLite version 126.96.36.199 is a patch release to version 3.6.14 with minimal changes that fixes three bugs. Upgrading is only necessary for users who are impacted by one or more of those bugs.
SQLite version 3.6.14 provides new performance enhancements in the btree and pager layers and in the query optimizer. Certain workloads can be as much as twice as fast as the previous release, though 10% faster is a more typical result.
Queries against virtual tables that contain OR and IN operators in the WHERE clause are now able to use indexing.
A new optional asynchronous I/O backend is available for unix and windows. The asynchronous backend gives the illusion of faster response time by pushing slow write operations into a background thread. The tradeoff for faster response time is that more memory is required (to hold the content of the pending writes) and if a power failure or program crash occurs, some transactions that appeared to have committed might end up being rolled back upon restart.
This release also contains many minor bug fixes, documentation enhancements, new test cases, and cleanups and simplifications to the source code.
There is no compelling reason to upgrade from versions 3.6.12 or 3.6.13 if those prior versions are working. Though many users may benefit from the improved performance.
SQLite version 3.6.7 contains a major cleanup of the Unix driver, and support for the new Proxy Locking mechanism on Mac OS X. Though the Unix driver is reorganized, its functionality is the same and so applications should not notice a difference.
This release fixes a bug that was introduced into SQLite version 3.6.6 and which seems like it might be able to cause database corruption. This bug was detected during stress testing. It has not been seen in the wild. An analysis of the problem suggests that the bug might be able to cause database corruption, however focused efforts to find a real-world test cases that actually causes database corruption have so far been unsuccessful. Hence, the likelihood of this bug causing problems is low. Nevertheless, we have decided to do an emergency branch release out of an abundance of caution.
The version 188.8.131.52 release also fixes an obscure memory leak that can occur following a disk I/O error.
This release fixes a bug that was introduced into SQLite version 3.6.4 and that can cause database corruption in obscure cases. This bug has never been seen in the wild; it was first detected by internal stress tests and required substantial analysis before it could be shown to potentially lead to corruption. So we feel that SQLite versions 3.6.4, 3.6.5, and 3.6.6 are safe to use for development work. But upgrading to this patch release or later is recommended prior to deploying products that incorporate SQLite.
We have taken the unusual step of issuing a patch release in order to get the fix for this bug into circulation quickly. SQLite version 3.6.7 will continue on its normal path of development with an anticipated release in mid December.
SQLite version 3.6.5 is released. This is a quick turn-around release that fixes a bug in virtual tables and FTS3 that snuck into version 3.6.5. This release also adds the new application-defined page cache mechanism.
SQLite version 3.6.5 is released. There are various minor feature enhancements and numerous obscure bug fixes. The change log contains the details. Upgrading is optional.
The SQLite developers are honored to announce that Bloomberg has joined the SQLite Consortium.
SQLite version 3.6.4 adds new features designed to help applications detect when indices are not being used on query. There are also some important performance improvements. Upgrading is optional.
SQLite version 3.6.3 fixes a bug in SELECT DISTINCT that was introduced by the previous version. No new features are added. Upgrading is recommended for all applications that make use of DISTINCT.
SQLite version 3.6.2 contains rewrites of the page-cache subsystem and the procedures for matching identifiers to table columns in SQL statements. These changes are designed to better modularize the code and make it more maintainable and reliable moving forward. Nearly 5000 non-comment lines of core code (about 11.3%) have changed from the previous release. Nevertheless, there should be no application-visible changes, other than bug fixes.
SQLite version 3.6.1 is a stabilization and performance enhancement release.
Version 3.6.0 makes changes to the VFS object in order to make SQLite more easily portable to a wider variety of platforms. There are potential incompatibilities with some legacy applications. See the 35to36.html document for details.
Many new interfaces are introduced in version 3.6.0. The code is very well tested and is appropriate for use in stable systems. We have attached the "beta" designation only so that we can make tweaks to the new interfaces in the next release without having to declare an incompatibility.
Version 3.5.9 adds a new experimental PRAGMA: journal_mode. Setting the journal mode to PERSIST can provide performance improvement on systems where deleting a file is expensive. The PERSIST journal mode is still considered experimental and should be used with caution pending further testing.
Version 3.5.9 is intended to be the last stable release prior to version 3.6.0. Version 3.6.0 will make incompatible changes to the sqlite3_vfs VFS layer in order to address deficiencies in the original design. These incompatibilities will only effect programmers who write their own custom VFS layers (typically embedded device builders). The planned VFS changes will be much smaller than the changes that occurred on the 3.4.2 to 3.5.0 transaction that occurred last September.
This release of SQLite is considered stable and ready for production use.
Version 3.5.8 includes some important new performance optimizations in the virtual machine code generator, including constant subexpression factoring and common subexpression elimination. This release also creates new public interfaces: sqlite3_randomness() provides access to SQLite's internal pseudo-random number generator, sqlite3_limit() allows size limits to be set at run-time on a per-connection basis, and sqlite3_context_db_handle() is a convenience routine that allows an application-defined SQL function implementation to retrieve its database connection handle.
This release of SQLite is considered stable and ready for production use.
Version 3.5.7 fixes several minor and obscure bugs, especially in the autoconf-generated makefile. Upgrading is optional. This release of SQLite is considered stable and ready for production use.
Version 3.5.6 fixes a minor regression in 3.5.5 - a regression that had nothing to do with the massive change of the virtual machine to a register-based design. No problems have been reported with the new virtual machine. This release of SQLite is considered stable and ready for production use.
Version 3.5.5 changes over 8% of the core source code of SQLite in order to convert the internal virtual machine from a stack-based design into a register-based design. This change will allow future optimizations and will avoid an entire class of stack overflow bugs that have caused problems in the past. Even though this change is large, extensive testing has found zero errors in the new virtual machine and so we believe this to be a very stable release.
Version 3.5.4 fixes a long-standing but obscure bug in UPDATE and DELETE which might cause database corruption. (See ticket #2832.) Upgrading is recommended for all users.
This release also brings the processing of ORDER BY statements into compliance with standard SQL. This could, in theory, cause problems for existing applications that depend on the older, buggy behavior. See ticket #2822 for additional information.
The SQLite Consortium was launched today with Mozilla and Symbian as charter members. As noted in the press release, the Consortium's goal is to promote the continuing vitality and independence of SQLite.
This is an incremental release that fixes several minor problems. Upgrading is optional. If Version 3.5.2 or 3.5.1 is working fine for you, then there is no pressing need to change to 3.5.3.
The prebuilt binaries and the amalgamation found on the download page include the FTS3 fulltext search extension module. We are doing this on an experimental basis and are not promising to provide prebuilt binaries with FTS3 in the future.
This is an incremental release that fixes several minor problems, adds some obscure features, and provides some performance tweaks. Upgrading is optional.
The experimental compile-time option SQLITE_OMIT_MEMORY_ALLOCATION is no longer supported. On the other hand, it is now possible to compile SQLite so that it uses a static array for all its dynamic memory allocation needs and never calls malloc. Expect to see additional radical changes to the memory allocation subsystem in future releases.
Fix a long-standing bug that might cause database corruption if a disk-full error occurs in the middle of a transaction and that transaction is not rolled back. Ticket #2686.
The new VFS layer is stable. However, we still reserve the right to make tweaks to the interface definition of the VFS if necessary.
The OS interface layer and the memory allocation subsystems in SQLite have been reimplemented. The published API is largely unchanged but the (unpublished) OS interface has been modified extensively. Applications that implement their own OS interface will require modification. See 34to35.html for details.
This is a large change. Approximately 10% of the source code was modified. We are calling this first release "alpha" in order to give the user community time to test and evaluate the changes before we freeze the new design.
While stress-testing the soft_heap_limit feature, a bug that could lead to database corruption was discovered and fixed. Though the consequences of this bug are severe, the chances of hitting it in a typical application are remote. Upgrading is recommended only if you use the sqlite3_soft_heap_limit interface.
This release fixes a bug in VACUUM that can lead to database corruption. The bug was introduced in version 3.3.14. Upgrading is recommended for all users. Also included are a slew of other more routine enhancements and bug fixes.
This release fixes two separate bugs either of which can lead to database corruption. Upgrading is strongly recommended. If you must continue using an older version of SQLite, please at least read about how to avoid these bugs at CorruptionFollowingBusyError and ticket #2418
This release also adds explicit limits on the sizes and quantities of things SQLite will handle. The new limits might causes compatibility problems for existing applications that use excessively large strings, BLOBs, tables, or SQL statements. The new limits can be increased at compile-time to work around any problems that arise. Nevertheless, the version number of this release is 3.4.0 instead of 3.3.18 in order to call attention to the possible incompatibility.There are also new features, including incremental BLOB I/O and incremental vacuum. See the change log for additional information.
This version fixes a bug in the forwards-compatibility logic of SQLite that was causing a database to become unreadable when it should have been read-only. Upgrade from 3.3.16 only if you plan to deploy into a product that might need to be upgraded in the future. For day to day use, it probably does not matter.
Performance improvements added in 3.3.14 but mistakenly turned off in 3.3.15 have been reinstated. A bug has been fixed that prevented VACUUM from running if a NULL value was in a UNIQUE column.
An annoying bug introduced in 3.3.14 has been fixed. There are also many enhancements to the test suite.
This version focuses on performance improvements. If you recompile the amalgamation using GCC option -O3 (the precompiled binaries use -O2) you may see performance improvements of 35% or more over version 3.3.13 depending on your workload. This version also adds support for exclusive access mode.
This version fixes a subtle bug in the ORDER BY optimizer that can occur when using joins. There are also a few minor enhancements. Upgrading is recommended.
The first published build of the previous version used the wrong set of source files. Consequently, many people downloaded a build that was labeled as "3.3.11" but was really 3.3.10. Version 3.3.12 is released to clear up the ambiguity. A couple more bugs have also been fixed and PRAGMA integrity_check has been enhanced.
Version 3.3.11 fixes for a few more problems in version 3.3.9 that version 3.3.10 failed to catch. Upgrading is recommended.
Version 3.3.10 fixes several bugs that were introduced by the previous release. Upgrading is recommended.
Version 3.3.9 fixes bugs that can lead to database corruption under obscure and difficult to reproduce circumstances. See DatabaseCorruption in the wiki for details. This release also adds the new sqlite3_prepare_v2() API and includes important bug fixes in the command-line shell and enhancements to the query optimizer. Upgrading is recommended.
Version 3.3.8 adds support for full-text search using the FTS1 module. There are also minor bug fixes. Upgrade only if you want to try out the new full-text search capabilities or if you are having problems with 3.3.7.
Version 3.3.7 includes support for loadable extensions and virtual tables. But both features are still considered "beta" and their APIs are subject to change in a future release. This release is mostly to make available the minor bug fixes that have accumulated since 3.3.6. Upgrading is not necessary. Do so only if you encounter one of the obscure bugs that have been fixed or if you want to try out the new features.
The Definitive Guide to SQLite, a new book by Mike Owens is now available from Apress. The books covers the latest SQLite internals as well as the native C interface and bindings for PHP, Python, Perl, Ruby, Tcl, and Java. Recommended.
Changes include improved tolerance for Windows virus scanners and faster :memory: databases. There are also fixes for several obscure bugs. Upgrade if you are having problems.
This release fixes many minor bugs and documentation typos and provides some minor new features and performance enhancements. Upgrade only if you are having problems or need one of the new features.
This release fixes several bugs, including a blunder that might cause a deadlock on multithreaded systems. Anyone using SQLite in a multithreaded environment should probably upgrade.
There have been no major problems discovered in version 3.3.2, so we hereby declare the new APIs and language features to be stable and supported.
More bug fixes and performance improvements as we move closer to a production-ready version 3.3.x.
Many bugs found in last week's alpha release have now been fixed and the library is running much faster again.
Database connections can now be moved between threads as long as the connection holds no locks at the time it is moved. Thus the common paradigm of maintaining a pool of database connections and handing them off to transient worker threads is now supported. Please help test this new feature. See the MultiThreading wiki page for additional information.
Version 3.3.0 adds support for CHECK constraints, DESC indices, separate REAL and INTEGER column affinities, a new OS interface layer design, and many other changes. The code passed a regression test but should still be considered alpha. Please report any problems.
The file format for version 3.3.0 has changed slightly to support descending indices and a more efficient encoding of boolean values. SQLite 3.3.0 will read and write legacy databases created with any prior version of SQLite 3. But databases created by version 3.3.0 will not be readable or writable by earlier versions of the SQLite. The older file format can be specified at compile-time for those rare cases where it is needed.
These versions contain one-line changes to 3.2.7 and 2.8.16 to fix a bug that has been present since March of 2002 and version 2.4.0. That bug might possibly cause database corruption if a large INSERT or UPDATE statement within a multi-statement transaction fails due to a uniqueness constraint but the containing transaction commits.
This version fixes several minor and obscure bugs. Upgrade only if you are having problems.
This version fixes a bug that can result in database corruption if a VACUUM of a 1 gigabyte or larger database fails (perhaps do to running out of disk space or an unexpected power loss) and is later rolled back.
Also in this release: The ORDER BY and GROUP BY processing was rewritten to use less memory. Support for COUNT(DISTINCT) was added. The LIKE operator can now be used by the optimizer on columns with COLLATE NOCASE.
This release fixes a few more lingering bugs in the new code. We expect that this release will be stable and ready for production use.
This release fixes a bug in the new optimizer that can lead to segfaults when parsing very complex WHERE clauses.
This release adds the ANALYZE command, the CAST operator, and many very substantial improvements to the query optimizer. See the change log for additional information.
SQLite and its primary author D. Richard Hipp have been honored with a 2005 Open Source Award from Google and O'Reilly.
This release includes numerous minor bug fixes, speed improvements, and code size reductions. There is no reason to upgrade unless you are having problems or unless you just want to.
This release fixes a memory allocation problem in the new ALTER TABLE ADD COLUMN command.
The primary purpose for version 3.2.0 is to add support for ALTER TABLE ADD COLUMN. The new ADD COLUMN capability is made possible by AOL developers supporting and embracing great open-source software. Thanks, AOL!
Version 3.2.0 also fixes an obscure but serious bug that was discovered just prior to release. If you have a multi-statement transaction and within that transaction an UPDATE or INSERT statement fails due to a constraint, then you try to rollback the whole transaction, the rollback might not work correctly. See Ticket #1171 for details. Upgrading is recommended for all users.
Version 3.1.6 fixes a critical bug that can cause database corruption when inserting rows into tables with around 125 columns. This bug was introduced in version 3.0.0. See Ticket #1163 for additional information.
Version 3.1.4 fixes a critical bug that could cause database corruption if the autovacuum mode of version 3.1.0 is turned on (it is off by default) and a CREATE UNIQUE INDEX is executed within a transaction but fails because the indexed columns are not unique. Anyone using the autovacuum feature and unique indices should upgrade.
Version 3.1.5 adds the ability to disable the F_FULLFSYNC ioctl() in OS-X by setting "PRAGMA synchronous=on" instead of the default "PRAGMA synchronous=full". There was an attempt to add this capability in 3.1.4 but it did not work due to a spelling error.
Version 3.1.3 cleans up some minor issues discovered in version 3.1.2.
A critical bug in the VACUUM command that can lead to database corruption has been fixed in both the 2.x branch and the main 3.x line. This bug has existed in all prior versions of SQLite. Even though it is unlikely you will ever encounter this bug, it is suggested that all users upgrade. See ticket #1116. for additional information.
Version 3.1.2 is also the first stable release of the 3.1 series. SQLite 3.1 features added support for correlated subqueries, autovacuum, autoincrement, ALTER TABLE, and other enhancements. See the release notes for version 3.1.0 for a detailed description of the changes available in the 3.1 series.
Version 3.1.1 (beta) is now available on the website. Version 3.1.1 is fully backwards compatible with the 3.0 series and features many new features including Autovacuum and correlated subqueries. The release notes From version 3.1.0 apply equally to this release beta. A stable release is expected within a couple of weeks.
Version 3.1.0 (alpha) is now available on the website. Version 3.1.0 is fully backwards compatible with the 3.0 series and features many new features including Autovacuum and correlated subqueries. See the release notes for details.
This is an alpha release. A beta release is expected in about a week with the first stable release to follow after two more weeks.
There was a talk on the architecture of SQLite and how to optimize SQLite queries at the 2004 International PHP Conference in Frankfurt, Germany. Slides from that talk are available.
Version 3.0.8 of SQLite contains several code optimizations and minor bug fixes and adds support for DEFERRED, IMMEDIATE, and EXCLUSIVE transactions. This is an incremental release. There is no reason to upgrade from version 3.0.7 if that version is working for you.
There will be a talk on the use of SQLite in Tcl/Tk at the 11th Tcl/Tk Conference this week in New Orleans. Visit http://www.tcl.tk/community/tcl2004/ for details. Slides from the talk are available.
Version 3.0 has now been in use by multiple projects for several months with no major difficulties. We consider it stable and ready for production use.
Because of some important changes to sqlite3_step(), we have decided to do an additional beta release prior to the first "stable" release. If no serious problems are discovered in this version, we will release version 3.0 "stable" in about a week.
The fourth beta release of SQLite version 3.0 is now available. The next release is expected to be called "stable".
The third beta release of SQLite version 3.0 is now available. This new beta fixes several bugs including a database corruption problem that can occur when doing a DELETE while a SELECT is pending. Expect at least one more beta before version 3.0 goes final.
The second beta release of SQLite version 3.0 is now available. This new beta fixes many bugs and adds support for databases with varying page sizes. The next 3.0 release will probably be called a final or stable release.
Version 3.0 adds support for internationalization and a new more compact file format. Details. The API and file format have been fixed since 3.0.2. All regression tests pass (over 100000 tests) and the test suite exercises over 95% of the code.
SQLite version 3.0 is made possible in part by AOL developers supporting and embracing great Open-Source Software.
SQLite version 2.8.15 is a maintenance release for the version 2.8 series. Version 2.8 continues to be maintained with bug fixes, but no new features will be added to version 2.8. All the changes in this release are minor. If you are not having problems, there is there is no reason to upgrade.
The first beta release of SQLite version 3.0 is now available. Version 3.0 adds support for internationalization and a new more compact file format. Details. As of this release, the API and file format are frozen. All regression tests pass (over 100000 tests) and the test suite exercises over 95% of the code.
SQLite version 3.0 is made possible in part by AOL developers supporting and embracing great Open-Source Software.
The www.sqlite.org website was hacked sometime around 2004-06-22 because the lead SQLite developer failed to properly patch CVS. Evidence suggests that the attacker was unable to elevate privileges above user "cvs". Nevertheless, as a precaution the entire website has been reconstructed from scratch on a fresh machine. All services should be back to normal as of 2004-06-28.
The first alpha release of SQLite version 3.0 is available for public review and comment. Version 3.0 enhances internationalization support through the use of UTF-16 and user-defined text collating sequences. BLOBs can now be stored directly, without encoding. A new file format results in databases that are 25% smaller (depending on content). The code is also a little faster. In spite of the many new features, the library footprint is still less than 240KB (x86, gcc -O1). Additional information.
Our intent is to freeze the file format and API on 2004-07-01. Users are encouraged to review and evaluate this alpha release carefully and submit any feedback prior to that date.
The 2.8 series of SQLite will continue to be supported with bug fixes for the foreseeable future.
SQLite version 2.8.14 is a patch release to the stable 2.8 series. There is no reason to upgrade if 2.8.13 is working ok for you. This is only a bug-fix release. Most development effort is going into version 3.0.0 which is due out soon.
Anonymous access to the CVS repository will be suspended for 2 weeks beginning on 2004-06-04. Everyone will still be able to download prepackaged source bundles, create or modify trouble tickets, or view change logs during the CVS service interruption. Full open access to the CVS repository will be restored on 2004-06-18.
Work has begun on version 3 of SQLite. Version 3 is a major changes to both the C-language API and the underlying file format that will enable SQLite to better support internationalization. The first beta is schedule for release on 2004-07-01.
Plans are to continue to support SQLite version 2.8 with bug fixes. But all new development will occur in version 3.0.