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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 3.8.7 (2014-10-17):

    Performance Enhancements:

16. Many micro-optimizations result in 20.3% more work for the same number of CPU cycles relative to the previous release. The cumulative performance increase since version 3.8.0 is 61%. (Measured using cachegrind on the speedtest1.c workload on Ubuntu 13.10 x64 with gcc 4.8.1 and -Os. Your performance may vary.)
17. The sorter can use auxiliary helper threads to increase real-time response. This feature is off by default and may be enabled using the PRAGMA threads command or the SQLITE_DEFAULT_WORKER_THREADS compile-time option.
18. Enhance the skip-scan optimization so that it is able to skip index terms that occur in the middle of the index, not just as the left-hand side of the index.
19. Improved optimization of CAST operators.
20. Various improvements in how the query planner uses sqlite_stat4 information to estimate plan costs.

    New Features:

21. Added new interfaces with 64-bit length parameters: sqlite3_malloc64(), sqlite3_realloc64(), sqlite3_bind_blob64(), sqlite3_result_blob64(), sqlite3_bind_text64(), and sqlite3_result_text64().
22. Added the new interface sqlite3_msize() that returns the size of a memory allocation obtained from sqlite3_malloc64() and its variants.
23. Added the SQLITE_LIMIT_WORKER_THREADS option to sqlite3_limit() and PRAGMA threads command for configuring the number of available worker threads.
24. The spellfix1 extension allows the application to optionally specify the rowid for each INSERT.
25. Added the User Authentication extension.

    Bug Fixes:

26. Fix a bug in the partial index implementation that might result in an incorrect answer if a partial index is used in a subquery or in a view. Ticket 98d973b8f5.
27. Fix a query planner bug that might cause a table to be scanned in the wrong direction (thus reversing the order of output) when a DESC index is used to implement the ORDER BY clause on a query that has an identical GROUP BY clause. Ticket ba7cbfaedc7e6.
28. Fix a bug in sqlite3_trace() that was causing it to sometimes fail to print an SQL statement if that statement needed to be re-prepared. Ticket 11d5aa455e0d98f3c1e6a08
29. Fix a faulty assert() statement. Ticket 369d57fb8e5ccdff06f1

    Test, Debug, and Analysis Changes:

30. Show ASCII-art abstract syntax tree diagrams using the ".selecttrace" and ".wheretrace" commands in the command-line shell when compiled with SQLITE_DEBUG, SQLITE_ENABLE_SELECTTRACE, and SQLITE_ENABLE_WHERETRACE. Also provide the sqlite3TreeViewExpr() and sqlite3TreeViewSelect() entry points that can be invoked from with the debugger to show the parse tree when stopped at a breakpoint.
31. Drop support for SQLITE_ENABLE_TREE_EXPLAIN. The SELECTTRACE mechanism provides more useful diagnostics information.
32. New options to the command-line shell for configuring auxiliary memory usage: --pagecache, --lookaside, and --scratch.

    Bug fixes backported into patch release 3.8.6 (2014-08-15):

33. Added support for hexadecimal integer literals in the SQL parser. (Ex: 0x123abc)
34. Enhanced the PRAGMA integrity_check command to detect UNIQUE and NOT NULL constraint violations.
35. Increase the maximum value of SQLITE_MAX_ATTACHED from 62 to 125.
36. Increase the timeout in WAL mode before issuing an SQLITE_PROTOCOL error from 1 second to 10 seconds.
37. Added the likely(X) SQL function.
38. The unicode61 tokenizer is now included in FTS4 by default.
39. Trigger automatic reprepares on all prepared statements when ANALYZE is run.
40. Added a new loadable extension source code file to the source tree: fileio.c
41. Add extension functions readfile(X) and writefile(X,Y) (using code copy/pasted from fileio.c in the previous bullet) to the command-line shell.
42. Added the .fullschema dot-command to the command-line shell.

    Performance Enhancements:

43. Deactivate the DISTINCT keyword on subqueries on the right-hand side of the IN operator.
44. Add the capability of evaluating an IN operator as a sequence of comparisons as an alternative to using a table lookup. Use the sequence of comparisons implementation in circumstances where it is likely to be faster, such as when the right-hand side of the IN operator is small and/or changes frequently.
45. The query planner now uses sqlite_stat4 information (created by ANALYZE) to help determine if the skip-scan optimization is appropriate.
46. Ensure that the query planner never tries to use a self-made transient index in place of a schema-defined index.
47. Other minor tweaks to improve the quality of VDBE code.

    Bug Fixes:

48. Fix a bug in CREATE UNIQUE INDEX, introduced when WITHOUT ROWID support added in version 3.8.2, that allows a non-unique NOT NULL column to be given a UNIQUE index. Ticket 9a6daf340df99ba93c
49. Fix a bug in R-Tree extension, introduced in the previous release, that can cause an incorrect results for queries that use the rowid of the R-Tree on the left-hand side of an IN operator. Ticket d2889096e7bdeac6.
50. Fix the sqlite3_stmt_busy() interface so that it gives the correct answer for ROLLBACK statements that have been stepped but never reset.
51. Fix a bug in that would cause a null pointer to be dereferenced if a column with a DEFAULT that is an aggregate function tried to usee its DEFAULT. Ticket 3a88d85f36704eebe1
52. CSV output from the command-line shell now always uses CRNL for the row separator and avoids inserting CR in front of NLs contained in data.
53. Fix a column affinity problem with the IN operator. Ticket 9a8b09f8e6.
54. Fix the ANALYZE command so that it adds correct samples for WITHOUT ROWID tables in the sqlite_stat4 table. Ticket b2fa5424e6fcb15.

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.