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## SQLite Release 3.8.1 On 2013-10-17

1. Added the unlikely() and likelihood() SQL functions to be used as hints to the query planner.
2. Enhancements to the query planner:
   1. Take into account the fact WHERE clause terms that cannot be used with indices still probably reduce the number of output rows.
   2. Estimate the sizes of table and index rows and use the smallest applicable B-Tree for full scans and "count(*)" operations.
3. Added the soft_heap_limit pragma.
4. Added support for SQLITE_ENABLE_STAT4
5. Added support for "sz=NNN" parameters at the end of sqlite_stat1.stat fields used to specify the average length in bytes for table and index rows.
6. Avoid running foreign-key constraint checks on an UPDATE if none of the modified columns are associated with foreign keys.
7. Added the SQLITE_MINIMUM_FILE_DESCRIPTOR compile-time option
8. Added the win32-longpath VFS on windows, permitting filenames up to 32K characters in length.
9. The Date And Time Functions are enhanced so that the current time (ex: julianday('now')) is always the same for multiple function invocations within the same sqlite3_step() call.
10. Add the "totype.c" extension, implementing the tointeger() and toreal() SQL functions.
11. FTS4 queries are better able to make use of docid<$limit constraints to limit the amount of I/O required.
12. Added the hidden fts4aux languageid column to the fts4aux virtual table.
13. The VACUUM command packs the database about 1% tighter.
14. The sqlite3_analyzer utility program is updated to provide better descriptions and to compute a more accurate estimate for "Non-sequential pages"
15. Refactor the implementation of PRAGMA statements to improve parsing performance.
16. The directory used to hold temporary files on unix can now be set using the SQLITE_TMPDIR environment variable, which takes precedence over the TMPDIR environment variable. The sqlite3_temp_directory global variable still has higher precedence than both environment variables, however.
17. Added the PRAGMA stats statement.
18. Bug fix: Return the correct answer for "SELECT count(*) FROM table" even if there is a partial index on the table. Ticket a5c8ed66ca.
19. SQLITE_SOURCE_ID: "2013-10-17 12:57:35 c78be6d786c19073b3a6730dfe3fb1be54f5657a"
20. SHA1 for sqlite3.c: 0a54d76566728c2ba96292a49b138e4f69a7c391

A complete list of SQLite releases in a single page and a chronology are both also available. A detailed history of every check-in is available at SQLite version control site.