SQLite 3.17.0 ソフトウェア情報交換

What's new in this version:

- Add the SQLITE_DEFAULT_LOOKASIDE compile-time option
- Increase the default lookaside size from 512,125 to 1200,100 as this provides better performance while only adding 56KB of extra memory per connection. Memory-sensitive applications can restore the old default at compile-time, start-time, or run-time
- Use compiler built-ins __builtin_sub_overflow(), __builtin_add_overflow(), and __builtin_mul_overflow() when available. (All compiler built-ins can be omitted with the SQLITE_DISABLE_INTRINSIC compile-time option.)
- Added the SQLITE_ENABLE_NULL_TRIM compile-time option, which can result in significantly smaller database files for some applications, at the risk of being incompatible with older versions of SQLite
- Change SQLITE_DEFAULT_PCACHE_INITSZ from 100 to 20, for improved performance
- Added the SQLITE_UINT64_TYPE compile-time option as an analog to SQLITE_INT64_TYPE
- Perform some UPDATE operations in a single pass instead of in two passes
- Enhance the session extension to support WITHOUT ROWID tables
- Fixed performance problems and potential stack overflows when creating views from multi-row VALUES clauses with hundreds of thousands of rows
- Added the sha1.c extension
- In the command-line shell, enhance the ".mode" command so that it restores the default column and row separators for modes "line", "list", "column", and "tcl"
- Enhance the SQLITE_DIRECT_OVERFLOW_READ option so that it works in WAL mode as long as the pages being read are not in the WAL file
- Enhance the LEMON parser generator so that it can store the parser object as a stack variable rather than allocating space from the heap and make use of that enhancement in the amalgamation
- Other performance improvements. Uses about 6.5% fewer CPU cycles

Approximately 25% better performance from the R-Tree extension:
- Uses compiler built-ins (ex: __builtin_bswap32() or _byteswap_ulong()) for byteswapping when available
- Uses the sqlite3_blob key/value access object instead of SQL for pulling content out of R-Tree nodes
- Other miscellaneous enhancements such as loop unrolling

Bug Fixes:
- Throw an error if the ON clause of a LEFT JOIN references tables to the right of the ON clause. This is the same behavior as PostgreSQL. Formerly, SQLite silently converted the LEFT JOIN into an INNER JOIN
- Use the correct affinity for columns of automatic indexes
- Ensure that the sqlite3_blob_reopen() interface can correctly handle short rows