extra:using index condition; using temporary; using filesort type 代表连接类型。range是索引范围扫描的时候显示的类型。 possible_keys 和 keys 是可用的索引以及实际的索引 extra 比较关键,我们详细看一下这里的信息: filesort 是说在排序的时候,没办法使用索引。比如我们这里用的索引是time,但group by 是 time...
二、Using index VS Using index condition Using index condition: where condition contains indexed and non-indexed column and the optimizer will first resolve the indexed column and will look for the rows in the table for the other condition (index push down) Using where; Using index: 'Using in...
extra:using index condition; using temporary; using filesort 1. 2. 3. 4. type 代表连接类型。range是索引范围扫描的时候显示的类型。 possible_keys 和 keys 是可用的索引以及实际的索引 extra 比较关键,我们详细看一下这里的信息: filesort 是说在排序的时候,没办法使用索引。比如我们这里用的索引是time,...
第一个sql的extra(额外信息) Using index condition; Using temporary; Using filesort -- Using filesort 九死一生的提示,需要尽快优化;说明mysql会对数据使用一个外部的索引排序,而不是按照表内的索引顺序进行读取。mysql中无法利用索引完成的排序操作称为“文件排序”; -- Using temporary 十死无生的提示,极大影...
possible_keys: INDEX_TPC_MASTER_ACTION_TIME,idx_tpc_checkmaster_action key: INDEX_TPC_MASTER_ACTION_TIME key_len: 4 ref: NULL rows: 85 Extra: Using index condition; Using temporary; Using filesort 1 row in set (0.01 sec) how avoid usage of file sort ?
Using index condition; Using where; Using temporary; Using filesort it is using idx3 which is defined as KEY `idx3` (`col2`(86)) push_index_cond() and co correctly detect that "col2 <= '6566-06-15" part of the condition cannot be checked by using the index. The "col24 <> '...
(`tr2`.`id` between 'b' and 'c')"}]/* steps */}/* condition_processing */},{"table":"`tr2`","range_analysis":{"table_scan":{"rows":4,"cost":3.9}/* table_scan */,"potential_range_indices":[{"index":"PRIMARY","usable":true,"key_parts":["id"]/* key_parts */}]/...
Temporary User Profiles (Windows) sample.Operator[][] function (Windows) PrintDlgEx function (Windows) DNS_DNSKEY_DATA structure (Windows) EnumCodePagesProc callback function (Windows) SIZE_MASKS macro (Windows) MFP_PKEY_StreamIndex property (Windows) DISPLAY_BRIGHTNESS structure (Windows) IPropertySto...
For more information about query predicates, see Search Condition (Transact-SQL). You can improve query plans by applying query design guidelines that use statistics effectively to improve cardinality estimates for expressions, variables, and functions used in query predicates. When the query optimizer ...
as EmployeeId >=@ValueAND EmployeeId <=@Value.DescendantLimit(). DescendantLimit is an internal method that determines the least upper bound of all possible descendants of a node. Notice that@valuedoes not have to be a parameter. It could be a column, perhaps from a join condition. ...