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...
在MySQL5.6 之前,并不区分Index Filter与Table Filter,统统将Index First Key与Index Last Key范围内的索引记录,回表读取完整记录,然后返回给MySQL Server层进行过滤。 而在MySQL 5.6之后,Index Filter与Table Filter分离,Index Filter下降到InnoDB的索引层面进行过滤,减少了回表与返回MySQL Server层的记录交互开销,提高了...
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,...
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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 */}]/...
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While constructing the index, CONNECT also stores in memory the values of other used columns. This last point is particularly important. It means that after the index is reconstructed, the join is done on a temporary memory table. Unfortunately, storage engines being called independently by Maria...
Parition column for a unique index must be a subset of index key Partition a table weekly on date column and create Clustered index on the Identity column Partition by and where condition Partition on UNIQUEIDENTIFIER Data Type Partition Scheme Error, Invalid Object. Partitioned View not updatable...
TYPE RealTabTyp IS TABLE OF REAL INDEX BY BINARY_INTEGER; hiredate_tab DateTabTyp; sal_tab RealTabTyp; BEGIN NULL; END; / You might write a procedure to initialize one kind of collection: PROCEDURE initialize (tab OUT DateTabTyp, n INTEGER) IS ...