SQLite Release 3.8.8.2 On 2015-01-30

• Enhance sqlite3_wal_checkpoint_v2(TRUNCATE) interface so that it truncates the WAL file even if there is no checkpoint work to be done.
• SQLITE_SOURCE_ID: "2015-01-30 14:30:45 7757fc721220e136620a89c9d28247f28bbbc098"
• SHA1 for sqlite3.c: 85ce79948116aa9a087ec345c9d2ce2c1d3cd8af

Changes carried forward from version 3.8.8.1 (2015-01-20):

• Fix a bug in the sorting logic, present since version 3.8.4, that can cause output to appear in the wrong order on queries that contains an ORDER BY clause, a LIMIT clause, and that have approximately 60 or more columns in the result set. Ticket f97c4637102a3ae72b79.

Changes carried forward from version 3.8.8 (2015-01-16):

New Features:

• Added the PRAGMA data_version command that can be used to determine if a database file has been modified by another process.
• Added the SQLITE_CHECKPOINT_TRUNCATE option to the sqlite3_wal_checkpoint_v2() interface, with corresponding enhancements to PRAGMA wal_checkpoint.
• Added the sqlite3_stmt_scanstatus() interface, available only when compiled with SQLITE_ENABLE_STMT_SCANSTATUS.
• The sqlite3_table_column_metadata() is enhanced to work correctly on WITHOUT ROWID tables and to check for the existence of a a table if the column name parameter is NULL. The interface is now also included in the build by default, without requiring the SQLITE_ENABLE_COLUMN_METADATA compile-time option.
• Added the SQLITE_ENABLE_API_ARMOR compile-time option.
• Added the SQLITE_REVERSE_UNORDERED_SELECTS compile-time option.
• Added the SQLITE_SORTER_PMASZ compile-time option and SQLITE_CONFIG_PMASZ start-time option.
• Added the SQLITE_CONFIG_PCACHE_HDRSZ option to sqlite3_config() which makes it easier for applications to determine the appropriate amount of memory for use with SQLITE_CONFIG_PAGECACHE.
• The number of rows in a VALUES clause is no longer limited by SQLITE_LIMIT_COMPOUND_SELECT.
• Added the eval.c loadable extension that implements an eval() SQL function that will recursively evaluate SQL.

  Performance Enhancements:

• Reduce the number of memcpy() operations involved in balancing a b-tree, for 3.2% overall performance boost.
• Improvements to cost estimates for the skip-scan optimization.
• The automatic indexing optimization is now capable of generating a partial index if that is appropriate.

  Bug fixes:

• Ensure durability following a power loss with "PRAGMA journal_mode=TRUNCATE" by calling fsync() right after truncating the journal file.
• The query planner now recognizes that any column in the right-hand table of a LEFT JOIN can be NULL, even if that column has a NOT NULL constraint. Avoid trying to optimize out NULL tests in those cases. Fix for ticket 6f2222d550f5b0ee7ed.
• Make sure ORDER BY puts rows in ascending order even if the DISTINCT operator is implemented using a descending index. Fix for ticket c5ea805691bfc4204b1cb9e.
• Fix data races that might occur under stress when running with many threads in shared cache mode where some of the threads are opening and closing connections.
• Fix obscure crash bugs found by american fuzzy lop. Ticket a59ae93ee990a55.
• Work around a GCC optimizer bug (for gcc 4.2.1 on MacOS 10.7) that caused the R-Tree extension to compute incorrect results when compiled with -O3.

  Other changes:

• Disable the use of the strchrnul() C-library routine unless it is specifically enabled using the -DHAVE_STRCHRNULL compile-time option.
• Improvements to the effectiveness and accuracy of the likelihood(), likely(), and unlikely() SQL hint functions.

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