3.3 同步数据至完整表中 1mysql>insertintousersselect*fromusers_part;//将1000w数据复制到未分区的完整表users 中2Query OK,10000000rows affected (51.59sec)3Records:10000000Duplicates:0Warnings:0 3.4 测试执行SQL的效率 1mysql>selectcount(
All rows in the table or query result will be partitioned and copied. Type: string (or Expression with resultType string). Parameters: partitionUpperBound - the partitionUpperBound value to set. Returns: the SqlPartitionSettings object itself....
#ERROR 1503 (HY000): A PRIMARY KEY must include all columns in the table's partitioning function mysql> ALTER TABLE np_pk -> PARTITION BY HASH(id) -> PARTITIONS 4; Query OK, 0 rows affected (0.11 sec) Records: 0 Duplicates: 0 Warnings: 0 [方法2] 将原有PK去掉生成新PK mysql> alter...
Partition elimination is very important when SQL Server executes queries against partitioned tables or partitioned views. In general, SQL Server is doing an excellent job of not scanning the partitions that are excluded by some predicates. Recently we have discovered one scenario where the partition ...
The query result of tablemath_gradeshows that the records previously stored in partitionmathhave been moved to tablestudent_grade. SELECT*FROMmath_grade; Figure 3math_grade query result Therow_clauseclause is used to set the row movement switch of a partitioned table. ...
in set (0.00 sec) mysql> UPDATE employees PARTITION (p2) -> SET store_id = 2 WHERE fname = 'Jill'; Query OK, 1 row affected (0.09 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT * FROM employees WHERE fname = 'Jill'; +---+---+---+---+---+ | id | fname...
Ordinarily, SQL Server can only perform an index seek on the second column of a multi-column index if there exists an equality predicate on the first column. Clearly, there is not an equality predicate on the [PtnId] column in this query and yet there is a predicate on column A. What...
2.发送你想要分析的sql语句,例如: select * from employees where first_name <'Bader' order by last_name; 1. 3.分析查询结果 select * from `information_schema`.optimizer_trace where query like '%Bader%'; 1. 得到如下结果: 分析trace结果: ...
Query examples Expression Results SELECT Partition(unitprice,40,240,20) AS PriceRange, count(productsales.unitprice) AS Count FROM productSales GROUP BY Partition(unitprice,40,240,20); Creates a set of ranges for the values in the field "unitprice" from "start"(40) to "stop"(240) ...
In MaxCompute, each value in a partition key column is specified as a partition. You can specify multi-level partitions with multiple partition key columns. Multi-level partitions are similar to multi-level directories in structure. Partitioned tables improve query efficiency. You can specify the ...