Date: 2011-05-09 00:37:46 +0200 (Mon, 09 May 2011)
New Revision: 26153
r47788@dhcp-adc-twvpn-1-vpnpool-10-154-13-87: paul | 2011-05-07 10:52:54 -0500
Some ICP fixups from Olav
Property changes on: trunk
Changed blocks: 0, Lines Added: 0, Lines Deleted: 0; 1277 bytes
--- trunk/refman-5.6/optimization.xml 2011-05-08 06:31:27 UTC (rev 26152)
+++ trunk/refman-5.6/optimization.xml 2011-05-08 22:37:46 UTC (rev 26153)
Changed blocks: 4, Lines Added: 16, Lines Deleted: 17; 3300 bytes
@@ -17897,10 +17897,10 @@
the MySQL server pushes this part of the
<literal>WHERE</literal> condition down to the storage engine.
The storage engine then evaluates the pushed index condition by
- using the index entry and only if this is satisfied is base row
- be read. ICP can reduce the number of accesses the storage
- engine has to do against the base table and the number of
- accesses the MySQL server has to do against the storage engine.
+ using the index entry and only if this is satisfied is the row
+ read from the table. ICP can reduce the number of times the
+ storage engine must access the base table and the number of
+ times the MySQL server must access the storage engine.
@@ -17958,21 +17958,22 @@
Test the part of the <literal>WHERE</literal> condition that
applies to this table and can be checked using only index
columns. If the condition is not satisfied, proceed to the
- next row.
+ index tuple for the next row.
- Use the index tuple to locate and read the full table row.
+ If the condition is satisfied, use the index tuple to locate
+ and read the full table row.
- Test the part of the <literal>WHERE</literal> condition that
- applies to this table. Accept or reject the row based on the
- test result.
+ Test the remaining part of the <literal>WHERE</literal>
+ condition that applies to this table. Accept or reject the
+ row based on the test result.
@@ -17999,7 +18000,7 @@
SELECT * FROM people
AND lastname LIKE '%etrunia%'
- AND address LIKE '%Main Street%'
+ AND address LIKE '%Main Street%';
@@ -18016,18 +18017,16 @@
<literal>lastname LIKE '%etrunia%'</literal> part before reading
the full table row. This avoids reading full rows corresponding
to all index tuples that do not match the
- <literal>lastname</literal> condition. The full-row test is
- <quote>pushed down</quote> to take place later than the
- index-only test.
+ <literal>lastname</literal> condition.
Index Condition Pushdown is enabled by default; it can be
controlled with the
- <literal role="sysvar">engine_condition_pushdown</literal>
- system variable. This variable also controls table Condition
- Pushdown as used for NDB; see
- <xref linkend="condition-pushdown-optimization"/>.
+ <literal role="sysvar">optimizer_switch</literal> system
+ variable by setting the
+ <literal>index_condition_pushdown</literal> flag. See
+ <xref linkend="switchable-optimizations"/>.
|• svn commit - mysqldoc@oter02: r26153 - in trunk: . refman-5.6||paul.dubois||9 May|