Changes 3.8.7:

Performance Enhancements:
* 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.)
* 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.
* 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.
* Improved optimization of CAST operators.
* Various improvements in how the query planner uses sqlite_stat4 information to estimate plan costs.

New Features:
* 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().
* Added the new interface sqlite3_msize() that returns the size of a memory allocation obtained from sqlite3_malloc64() and its variants.
* Added the SQLITE_LIMIT_WORKER_THREADS option to sqlite3_limit() and PRAGMA threads command for configuring the number of available worker threads.
* The spellfix1 extension allows the application to optionally specify the rowid for each INSERT.
* Added the User Authentication extension.

Bug Fixes:
* 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.
* 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.
* 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.
* Fix a faulty assert() statement.


(adam)