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Overview
Comment:Further enhancements to the change log for 3.20.0.
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: 4e0e4a8084327c63ff4f1aa06a530a524c520d79f1ab648dea9d39ec726c52b2
User & Date: drh 2017-07-21 19:39:53
Context
2017-07-23
20:57
Improved documentation on the pointer-passing interfaces. check-in: 9bf45f99e1 user: drh tags: trunk
2017-07-21
19:39
Further enhancements to the change log for 3.20.0. check-in: 4e0e4a8084 user: drh tags: trunk
19:32
Add the enhanced ability for date/time functions to be deterministic to the change log and to the "deterministic function" documentation. check-in: e27224b526 user: drh tags: trunk
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     done for top-level loops.
<li> The query planner examines the values of bound parameters to help
     determine if a partial index is usable.
<li> When deciding between two plans with the same estimated cost, bias 
     the selection toward the one that does not use the sorter.
<li> Evaluate WHERE clause constraints involving correlated subqueries
     last, in the hope that they never have be evaluated at all.




</ul>
<li> Add [SQLITE_STMTSTATUS_REPREPARE], [SQLITE_STMTSTATUS_RUN], 
     and [SQLITE_STMTSTATUS_MEMUSED] options for the
     [sqlite3_stmt_status()] interface.
<li> Provide [PRAGMA functions] for
     [PRAGMA integrity_check], [PRAGMA quick_check], and
     [PRAGMA foreign_key_check].
................................................................................
     the number of bytes of metadata on btree pages.
<li> The [SQLITE_DBCONFIG_ENABLE_QPSG] run-time option and the
     [SQLITE_ENABLE_QPSG] compile-time option enable the
     [query planner stability guarantee].  See also ticket
     [https://www.sqlite.org/src/info/892fc34f173e99d8|892fc34f173e99d8]
<li> Miscellaneous optimizations result in a 2% reduction in CPU cycles.
<p><b>Bug Fixes:</b>



<li> Ensure that the query planner knows that any column of a 
     [flattening optimization|flattened] LEFT JOIN can be NULL even 
     if that column is labeled with "NOT NULL". Fix for ticket 
     [https://sqlite.org/src/info/892fc34f173e99d8|892fc34f173e99d8].
<li> Fix rare false-positives in [PRAGMA integrity_check] when run on a database connection
     with [ATTACH|attached databases]. Ticket
     [https://sqlite.org/src/info/a4e06e75a9ab61a12|a4e06e75a9ab61a12]







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     done for top-level loops.
<li> The query planner examines the values of bound parameters to help
     determine if a partial index is usable.
<li> When deciding between two plans with the same estimated cost, bias 
     the selection toward the one that does not use the sorter.
<li> Evaluate WHERE clause constraints involving correlated subqueries
     last, in the hope that they never have be evaluated at all.
<li> Do not use the [flattening optimization] for a sub-query on the RHS 
     of a LEFT JOIN if that subquery reads data from a [virtual table] as
     doing so prevents the query planner from creating [automatic indexes]
     on the results of the sub-query, which can slow down the query.
</ul>
<li> Add [SQLITE_STMTSTATUS_REPREPARE], [SQLITE_STMTSTATUS_RUN], 
     and [SQLITE_STMTSTATUS_MEMUSED] options for the
     [sqlite3_stmt_status()] interface.
<li> Provide [PRAGMA functions] for
     [PRAGMA integrity_check], [PRAGMA quick_check], and
     [PRAGMA foreign_key_check].
................................................................................
     the number of bytes of metadata on btree pages.
<li> The [SQLITE_DBCONFIG_ENABLE_QPSG] run-time option and the
     [SQLITE_ENABLE_QPSG] compile-time option enable the
     [query planner stability guarantee].  See also ticket
     [https://www.sqlite.org/src/info/892fc34f173e99d8|892fc34f173e99d8]
<li> Miscellaneous optimizations result in a 2% reduction in CPU cycles.
<p><b>Bug Fixes:</b>
<li> Fix the query planner so that it knows not to use [automatic indexes]
     on the right table of LEFT JOIN if the WHERE clause uses the [IS operator].
     Fix for [https://sqlite.org/src/info/ce68383bf6aba|ce68383bf6aba].
<li> Ensure that the query planner knows that any column of a 
     [flattening optimization|flattened] LEFT JOIN can be NULL even 
     if that column is labeled with "NOT NULL". Fix for ticket 
     [https://sqlite.org/src/info/892fc34f173e99d8|892fc34f173e99d8].
<li> Fix rare false-positives in [PRAGMA integrity_check] when run on a database connection
     with [ATTACH|attached databases]. Ticket
     [https://sqlite.org/src/info/a4e06e75a9ab61a12|a4e06e75a9ab61a12]