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## SQLite Release 3.13.0 On 2016-05-18

1. Postpone I/O associated with TEMP files for as long as possible, with the hope that the I/O can ultimately be avoided completely.
2. Merged the session extension into trunk.
3. Added the ".auth ON|OFF" command to the command-line shell.
4. Added the "--indent" option to the ".schema" and ".fullschema" commands of the command-line shell, to turn on pretty-printing.
5. Added the ".eqp full" option to the command-line shell, that does both EXPLAIN and EXPLAIN QUERY PLAN on each statement that is evaluated.
6. Improved unicode filename handling in the command-line shell on Windows.
7. Improved resistance against goofy query planner decisions caused by incomplete or incorrect modifications to the sqlite_stat1 table by the application.
8. Added the sqlite3_db_config(db,SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION) interface which allows the sqlite3_load_extension() C-API to be enabled while keeping the load_extension() SQL function disabled for security.
9. Change the temporary directory search algorithm on Unix to allow directories with write and execute permission, but without read permission, to serve as temporary directories. Apply this same standard to the "." fallback directory.

   Bug Fixes:

10. Fix a problem with the multi-row one-pass DELETE optimization that was causing it to compute incorrect answers with a self-referential subquery in the WHERE clause. Fix for ticket dc6ebeda9396087
11. Fix a possible segfault with DELETE when table is a rowid table with an INTEGER PRIMARY KEY and the WHERE clause contains a OR and the table has one or more indexes that are able to trigger the OR optimization, but none of the indexes reference any table columns other than the INTEGER PRIMARY KEY. Ticket 16c9801ceba49.
12. When checking for the WHERE-clause push-down optimization, verify that all terms of the compound inner SELECT are non-aggregate, not just the last term. Fix for ticket f7f8c97e97597.
13. Fix a locking race condition in Windows that can occur when two or more processes attempt to recover the same hot journal at the same time.

    Hashes:

14. SQLITE_SOURCE_ID: "2016-05-18 10:57:30 fc49f556e48970561d7ab6a2f24fdd7d9eb81ff2"
15. SHA1 for sqlite3.c: 9b9171b1e6ce7a980e6b714e9c0d9112657ad552

    Bug fixes backported into patch release 3.8.2 (2013-12-06):

16. Changed the defined behavior for the CAST expression when floating point values greater than +9223372036854775807 are cast into into integers so that the result is the largest possible integer, +9223372036854775807, instead of the smallest possible integer, -9223372036854775808. After this change, CAST(9223372036854775809.0 as INT) yields +9223372036854775807 instead of -9223372036854775808. ← Potentially Incompatible Change!
17. Added support for WITHOUT ROWID tables.
18. Added the skip-scan optimization to the query planner.
19. Extended the virtual table interface, and in particular the sqlite3_index_info object to allow a virtual table to report its estimate on the number of rows that will be returned by a query.
20. Update the R-Tree extension to make use of the enhanced virtual table interface.
21. Add the SQLITE_ENABLE_EXPLAIN_COMMENTS compile-time option.
22. Enhanced the comments that are inserted into EXPLAIN output when the SQLITE_ENABLE_EXPLAIN_COMMENTS compile-time option is enabled.
23. Performance enhancements in the VDBE, especially to the OP_Column opcode.
24. Factor constant subexpressions in inner loops out to the initialization code in prepared statements.
25. Enhanced the ".explain" output formatting of the command-line shell so that loops are indented to better show the structure of the program.
26. Enhanced the ".timer" feature of the command-line shell so that it shows wall-clock time in addition to system and user times.

    Bug fixes backported into patch release 3.8.1 (2013-10-17):

27. Added the unlikely() and likelihood() SQL functions to be used as hints to the query planner.
28. 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.
29. Added the soft_heap_limit pragma.
30. Added support for SQLITE_ENABLE_STAT4
31. 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.
32. Avoid running foreign-key constraint checks on an UPDATE if none of the modified columns are associated with foreign keys.
33. Added the SQLITE_MINIMUM_FILE_DESCRIPTOR compile-time option
34. Added the win32-longpath VFS on windows, permitting filenames up to 32K characters in length.
35. 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.
36. Add the "totype.c" extension, implementing the tointeger() and toreal() SQL functions.
37. FTS4 queries are better able to make use of docid<$limit constraints to limit the amount of I/O required.
38. Added the hidden fts4aux languageid column to the fts4aux virtual table.
39. The VACUUM command packs the database about 1% tighter.
40. The sqlite3_analyzer utility program is updated to provide better descriptions and to compute a more accurate estimate for "Non-sequential pages"
41. Refactor the implementation of PRAGMA statements to improve parsing performance.
42. 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.
43. Added the PRAGMA stats statement.
44. Bug fix: Return the correct answer for "SELECT count(*) FROM table" even if there is a partial index on the table. Ticket a5c8ed66ca.

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.