Mysql分区表的管理与维护
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2023-12-19 13:49:58
改变一个表的分区方案只需使用alter table 加 partition_options 子句就可以了。和创建分区表时的create table语句很像。
创建表...
改变一个表的分区方案只需使用alter table 加 partition_options 子句就可以了。和创建分区表时的create table语句很像。
创建表
create table trb3 (id int, name varchar(50), purchased date) partition by range( year(purchased) ) ( partition p0 values less than (1990), partition p1 values less than (1995), partition p2 values less than (2000), partition p3 values less than (2005) );
创建插入数据存储过程
delimiter $$ drop procedure if exists pr_trb3$$ create procedure pr_trb3(in begindate date,in enddate date,in tabname varchar(40)) begin while begindate<enddate 1="" begindate="date_add(begindate,interval" delimiter="" do="" drop="" end="" execute="" from="" insert="" pre="" prepare="" s="concat_ws('" set="" stmt=""><p>调用存储过程插入数据</p><pre class="brush:sql;">call pr_trb3('1985-01-01','2004-12-31','trb3');</pre> <p>查看数据分布</p> <pre class="brush:sql;">select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.00 sec)</pre> <p>改变分区方案</p> <pre class="brush:sql;">mysql> alter table trb3 partition by key(id) partitions 4; query ok, 7304 rows affected (0.07 sec) records: 7304 duplicates: 0 warnings: 0</pre> <p>查看数据</p> <pre class="brush:sql;">select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='trb3'; +------+------+-------+------------+ | part | expr | descr | table_rows | +------+------+-------+------------+ | p0 | `id` | null | 7472 | | p1 | `id` | null | 0 | | p2 | `id` | null | 0 | | p3 | `id` | null | 0 | +------+------+-------+------------+ 4 rows in set (0.00 sec) mysql> select 1826*4; +--------+ | 1826*4 | +--------+ | 7304 | +--------+ 1 row in set (0.00 sec)</pre> <p>count(*)行数一致,说明数据没出问题,但是information_schema.partitions查出来的不对<del>,这就不知道为什么了</del></p> <blockquote> <p>for partitioned innodb tables, the row count given in the table_rows column of the information_schema.partitions table is only an estimated value used in sql optimization, and is not always exact.</p> </blockquote> <pre class="brush:sql;">mysql> select count(*) from trb3; +----------+ | count(*) | +----------+ | 7304 | +----------+ 但是count(*)还是7304,什么鬼</pre> <p>再次改变分区方案</p> <pre class="brush:sql;">alter table trb3 partition by range( year(purchased) ) ( partition p0 values less than (1990), partition p1 values less than (1995), partition p2 values less than (2000), partition p3 values less than (2005) ); mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 0 | | p3 | year(purchased) | 2005 | 0 | +------+------------------+-------+------------+ 4 rows in set (0.00 sec)</pre> <p><del>丢数据了。。</del><br> 更正,实际没丢,这个information_shcema.partitions表有延迟,过一会再查就好了</p> <pre class="brush:sql;">mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.00 sec)</pre> <p>官方文档说:<br> this has the same effect on the structure of the table as dropping the table and re-creating it using create table trb3 partition by key(id) partitions 2;<br> 就是说alter table trb3 partition by与 drop table然后重新create table trb3 partition by key(id) partitions 2一样呢。</p> <h3 id="改存储引擎和普通表没啥区别">改存储引擎,和普通表没啥区别</h3> <pre class="brush:sql;">mysql> drop table trb3; query ok, 0 rows affected (0.01 sec) mysql> create table trb3 (id int, name varchar(50), purchased date) -> partition by range( year(purchased) ) ( -> partition p0 values less than (1990), -> partition p1 values less than (1995), -> partition p2 values less than (2000), -> partition p3 values less than (2005) -> ); query ok, 0 rows affected (0.03 sec) mysql> call pr_trb3('1985-01-01','2004-12-31','trb3'); query ok, 0 rows affected (1.69 sec) mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.01 sec) mysql> alter table trb3 engine=myisam; query ok, 7304 rows affected (0.02 sec) records: 7304 duplicates: 0 warnings: 0 mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.01 sec) mysql> show create table trb3\g *************************** 1. row *************************** table: trb3 create table: create table `trb3` ( `id` int(11) default null, `name` varchar(50) default null, `purchased` date default null ) engine=myisam default charset=utf8 /*!50100 partition by range ( year(purchased)) (partition p0 values less than (1990) engine = myisam, partition p1 values less than (1995) engine = myisam, partition p2 values less than (2000) engine = myisam, partition p3 values less than (2005) engine = myisam) */ 1 row in set (0.00 sec)</pre> <h3 id="将表由分区表改为非分区表">将表由分区表改为非分区表</h3> <pre class="brush:sql;">mysql> alter table trb3 remove partitioning; query ok, 7304 rows affected (0.01 sec) records: 7304 duplicates: 0 warnings: 0 mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------+-------+------------+ | part | expr | descr | table_rows | +------+------+-------+------------+ | null | null | null | 7304 | +------+------+-------+------------+ 1 row in set (0.00 sec) mysql> show create table trb3\g *************************** 1. row *************************** table: trb3 create table: create table `trb3` ( `id` int(11) default null, `name` varchar(50) default null, `purchased` date default null ) engine=myisam default charset=utf8 1 row in set (0.00 sec)</pre> <h3 id="range-list分区管理">range list分区管理</h3> <pre class="brush:sql;">mysql> drop table trb3; query ok, 0 rows affected (0.01 sec) mysql> create table trb3 (id int, name varchar(50), purchased date) -> partition by range( year(purchased) ) ( -> partition p0 values less than (1990), -> partition p1 values less than (1995), -> partition p2 values less than (2000), -> partition p3 values less than (2005) -> ); query ok, 0 rows affected (0.03 sec) mysql> call pr_trb3('1985-01-01','2004-12-31','trb3'); query ok, 0 rows affected (1.75 sec) mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.00 sec)</pre> <h4 id="增加分区">增加分区</h4> <pre class="brush:sql;">mysql> alter table trb3 add partition (partition p5 values less than(2010)); query ok, 0 rows affected (0.00 sec) records: 0 duplicates: 0 warnings: 0</pre> <h4 id="合并分区">合并分区</h4> <pre class="brush:sql;">mysql> alter table trb3 reorganize partition p3,p5 into(partition p5 values less than(2010)); query ok, 1826 rows affected (0.03 sec) records: 1826 duplicates: 0 warnings: 0 mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p5 | year(purchased) | 2010 | 1826 | +------+------------------+-------+------------+ 4 rows in set (0.00 sec)</pre> <h4 id="分裂分区">分裂分区</h4> <pre class="brush:sql;">mysql> alter table trb3 reorganize partition p5 into ( -> partition p3 values less than (2005), -> partition p4 values less than (2010) -> ); query ok, 1826 rows affected (0.04 sec) records: 1826 duplicates: 0 warnings: 0 select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | 1990 | 1826 | | p1 | year(purchased) | 1995 | 1826 | | p2 | year(purchased) | 2000 | 1826 | | p3 | year(purchased) | 2005 | 1826 | | p4 | year(purchased) | 2010 | 0 | +------+------------------+-------+------------+ 5 rows in set (0.00 sec)</pre> <h3 id="hash-key分区">hash key分区</h3> <pre class="brush:sql;">create table trb3 (id int, name varchar(50), purchased date) partition by hash( year(purchased) ) partitions 12; mysql>call pr_trb3('1985-01-01','2004-12-31','trb3'); select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | null | 731 | | p1 | year(purchased) | null | 365 | | p2 | year(purchased) | null | 365 | | p3 | year(purchased) | null | 365 | | p4 | year(purchased) | null | 366 | | p5 | year(purchased) | null | 730 | | p6 | year(purchased) | null | 730 | | p7 | year(purchased) | null | 730 | | p8 | year(purchased) | null | 732 | | p9 | year(purchased) | null | 730 | | p10 | year(purchased) | null | 730 | | p11 | year(purchased) | null | 730 | +------+------------------+-------+------------+ 12 rows in set (0.00 sec)</pre> <h4 id="缩建分区从12个到8个">缩建分区从12个到8个</h4> <pre class="brush:sql;">mysql> alter table trb3 coalesce partition 4; query ok, 7304 rows affected (0.13 sec) records: 7304 duplicates: 0 warnings: 0 select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='trb3'; +------+------------------+-------+------------+ | part | expr | descr | table_rows | +------+------------------+-------+------------+ | p0 | year(purchased) | null | 732 | | p1 | year(purchased) | null | 1095 | | p2 | year(purchased) | null | 1095 | | p3 | year(purchased) | null | 1095 | | p4 | year(purchased) | null | 1097 | | p5 | year(purchased) | null | 730 | | p6 | year(purchased) | null | 730 | | p7 | year(purchased) | null | 730 | +------+------------------+-------+------------+ 8 rows in set (0.00 sec) mysql> select count(*) from trb3; +----------+ | count(*) | +----------+ | 7304 | +----------+ 1 row in set (0.00 sec)</pre> <p>没丢数据</p> <p>收缩前2004年在p0</p> <pre class="brush:sql;">mysql> select mod(2004,12); +--------------+ | mod(2004,12) | +--------------+ | 0 | +--------------+</pre> <p>收缩后2004年在p4</p> <pre class="brush:sql;">mysql> select mod(2004,8); +-------------+ | mod(2004,8) | +-------------+ | 4 | +-------------+</pre> <h3 id="exchanging-partitions-and-subpartitions-with-tables">exchanging partitions and subpartitions with tables</h3> <h3 id="分区子分区交换">分区(子分区)交换</h3> <pre class="brush:sql;"> alter table pt exchange partition p with table nt</pre> <p>pt是一个分区表,p是pt的分区或子分区,而nt是一个非分区表</p> <h4 id="限制条件">限制条件:</h4> <p>1.表nt不是分区表<br> 2.表nt不是临时表<br> 3.表pt和nt结构在其他方面是相同的<br> 4.表n没有外键约束,也没有其他表引用它的列为外键<br> 5.表nt的所有行都包含在表p的分区范围内(比如p range分区最大values less than 10,那么表nt不能有大于等于10的值)</p> <h4 id="权限">权限:</h4> <p>除了 alter, insert, and create 权限外,你还要有drop权限才能执行alter table … exchange partition.</p> <h4 id="其他注意事项">其他注意事项:</h4> <p>1.执行alter table … exchange partition 不会调用任何在nt表和p表上的触发器<br> 2.在交换表中的任何auto_increment列会被reset<br> 3.ignore关键字在执行alter table … exchange partition时会失效</p> <h4 id="完整实例语句如下">完整实例语句如下:</h4> <pre class="brush:sql;">alter table pt exchange partition p with table nt;</pre> <p>在一次alter table exchange partition 中,只能有一个分区和一个非分区表被交换<br> 想交换多个,就执行多次alter table exchange partition<br> 任何mysql支持的分区类型都可以进行交换</p> <h4 id="交换实例">交换实例</h4> <pre class="brush:sql;">create table e ( id int not null, fname varchar(30), lname varchar(30) ) partition by range (id) ( partition p0 values less than (50), partition p1 values less than (100), partition p2 values less than (150), partition p3 values less than (maxvalue) ); insert into e values (1669, "jim", "smith"), (337, "mary", "jones"), (16, "frank", "white"), (2005, "linda", "black");</pre> <p>创建一个与e结构一样的非分区表e2</p> <pre class="brush:sql;">mysql> create table e2 like e; query ok, 0 rows affected (0.01 sec) mysql> show create table e2\g *************************** 1. row *************************** table: e2 create table: create table `e2` ( `id` int(11) not null, `fname` varchar(30) default null, `lname` varchar(30) default null ) engine=innodb default charset=utf8 /*!50100 partition by range (id) (partition p0 values less than (50) engine = innodb, partition p1 values less than (100) engine = innodb, partition p2 values less than (150) engine = innodb, partition p3 values less than maxvalue engine = innodb) */ 1 row in set (0.00 sec) mysql> alter table e2 remove partitioning; query ok, 0 rows affected (0.02 sec) records: 0 duplicates: 0 warnings: 0 mysql> show create table e2\g *************************** 1. row *************************** table: e2 create table: create table `e2` ( `id` int(11) not null, `fname` varchar(30) default null, `lname` varchar(30) default null ) engine=innodb default charset=utf8 1 row in set (0.00 sec)</pre> <p>查看数据在e表中的分布:</p> <pre class="brush:sql;">select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='e' +------+------+----------+------------+ | part | expr | descr | table_rows | +------+------+----------+------------+ | p0 | id | 50 | 1 | | p1 | id | 100 | 0 | | p2 | id | 150 | 0 | | p3 | id | maxvalue | 3 | +------+------+----------+------------+ 4 rows in set (0.00 sec)</pre> <p>将分区p0与e2表进行交换:</p> <pre class="brush:sql;">mysql> alter table e exchange partition p0 with table e2; query ok, 0 rows affected (0.01 sec) select partition_name part, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='e'; +------+------+----------+------------+ | part | expr | descr | table_rows | +------+------+----------+------------+ | p0 | id | 50 | 0 | | p1 | id | 100 | 0 | | p2 | id | 150 | 0 | | p3 | id | maxvalue | 3 | +------+------+----------+------------+ 4 rows in set (0.01 sec) mysql> select * from e2; +----+-------+-------+ | id | fname | lname | +----+-------+-------+ | 16 | frank | white | +----+-------+-------+ 1 row in set (0.00 sec) </pre> <p>重做实验,这次在交换前在表e2中插入一些数据</p> <pre class="brush:sql;">mysql> insert into e2 values(16,'fan','boshi'); query ok, 1 row affected (0.00 sec) mysql> insert into e2 values(51,'du','yalan'); query ok, 1 row affected (0.00 sec) mysql> select * from e2; +----+-------+-------+ | id | fname | lname | +----+-------+-------+ | 16 | fan | boshi | | 51 | du | yalan | +----+-------+-------+ 2 rows in set (0.00 sec) mysql> alter table e exchange partition p0 with table e2; error 1737 (hy000): found a row that does not match the partition</pre> <p>报错了,因为51超出了p0的范围。<br> 如之前所说,此时使用ignore也无济于事</p> <pre class="brush:sql;">mysql> alter ignore table e exchange partition p0 with table e2; error 1737 (hy000): found a row that does not match the partition</pre> <p>修改id为49,这样就属于p0的范围了</p> <pre class="brush:sql;">mysql> update e2 set id=49 where id=51; query ok, 1 row affected (0.00 sec) rows matched: 1 changed: 1 warnings: 0 mysql> alter table e exchange partition p0 with table e2; query ok, 0 rows affected (0.01 sec) mysql> select -> partition_name part, -> partition_expression expr, -> partition_description descr, -> table_rows -> from information_schema.partitions where -> table_schema = schema() -> and table_name='e'; +------+------+----------+------------+ | part | expr | descr | table_rows | +------+------+----------+------------+ | p0 | id | 50 | 2 | | p1 | id | 100 | 0 | | p2 | id | 150 | 0 | | p3 | id | maxvalue | 3 | +------+------+----------+------------+ 4 rows in set (0.00 sec) e2的数据被交换到了p0中 mysql> select * from e partition(p0); +----+-------+-------+ | id | fname | lname | +----+-------+-------+ | 16 | fan | boshi | | 49 | du | yalan | +----+-------+-------+ 2 rows in set (0.00 sec) e的p0分区中的数据被交换到了e2中 mysql> select * from e2; +----+-------+-------+ | id | fname | lname | +----+-------+-------+ | 16 | frank | white | +----+-------+-------+ 1 row in set (0.01 sec)</pre> <h4 id="交换subpartition">交换subpartition</h4> <pre class="brush:sql;">create table es ( id int not null, fname varchar(30), lname varchar(30) ) partition by range (id) subpartition by key (lname) subpartitions 2 ( partition p0 values less than (50), partition p1 values less than (100), partition p2 values less than (150), partition p3 values less than (maxvalue) ); insert into es values (1669, "jim", "smith"), (337, "mary", "jones"), (16, "frank", "white"), (2005, "linda", "black"); create table es2 like es; alter table es2 remove partitioning;</pre> <p>尽管我们没有显示的指定每个子分区的名字,我们仍可以通过information_schema.partitions表获取到子分区的名字</p> <pre class="brush:sql;">select partition_name part, subpartition_name, partition_expression expr, partition_description descr, table_rows from information_schema.partitions where table_schema = schema() and table_name='es'; +------+-------------------+------+----------+------------+ | part | subpartition_name | expr | descr | table_rows | +------+-------------------+------+----------+------------+ | p0 | p0sp0 | id | 50 | 1 | | p0 | p0sp1 | id | 50 | 0 | | p1 | p1sp0 | id | 100 | 0 | | p1 | p1sp1 | id | 100 | 0 | | p2 | p2sp0 | id | 150 | 0 | | p2 | p2sp1 | id | 150 | 0 | | p3 | p3sp0 | id | maxvalue | 3 | | p3 | p3sp1 | id | maxvalue | 0 | +------+-------------------+------+----------+------------+</pre> <p>接下来,开始将p3sp0和es进行交换</p> <pre class="brush:sql;">mysql> select * from es partition(p3sp0); +------+-------+-------+ | id | fname | lname | +------+-------+-------+ | 1669 | jim | smith | | 337 | mary | jones | | 2005 | linda | black | +------+-------+-------+ 3 rows in set (0.00 sec) mysql> alter table es exchange partition p3sp0 with table es2; query ok, 0 rows affected (0.00 sec) mysql> select * from es partition(p3sp0); empty set (0.00 sec) mysql> select * from es2; +------+-------+-------+ | id | fname | lname | +------+-------+-------+ | 1669 | jim | smith | | 337 | mary | jones | | 2005 | linda | black | +------+-------+-------+ 3 rows in set (0.00 sec)</pre> <p>如果一个分区表有子分区,那么你只能以子分区为粒度进行交换,而不能直接交换子分区的父分区</p> <pre class="brush:sql;">mysql> alter table es exchange partition p3 with table es2; error 1704 (hy000): subpartitioned table, use subpartition instead of partition</pre> <p>exchange partition有着严格的要求<br> 两个将要交换的表的 列名,列的创建顺序,列的数量,以及索引都要严格一致。当然存储引擎也要一致</p> <pre class="brush:sql;">mysql> desc es2; +-------+-------------+------+-----+---------+-------+ | field | type | null | key | default | extra | +-------+-------------+------+-----+---------+-------+ | id | int(11) | no | | null | | | fname | varchar(30) | yes | | null | | | lname | varchar(30) | yes | | null | | +-------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec) mysql> create index id_name on es2(id,fname); query ok, 0 rows affected (0.01 sec) records: 0 duplicates: 0 warnings: 0 mysql> alter table es exchange partition p3sp0 with table es2; error 1736 (hy000): tables have different definitions</pre> <p>改变es2的存储引擎</p> <pre class="brush:sql;">mysql> drop index id_name on es2; query ok, 0 rows affected (0.00 sec) records: 0 duplicates: 0 warnings: 0 mysql> alter table es2 engine=myisam; query ok, 0 rows affected (0.01 sec) records: 0 duplicates: 0 warnings: 0 mysql> alter table es exchange partition p3sp0 with table es2; error 1497 (hy000): the mix of handlers in the partitions is not allowed in this version of mysql</pre> <h3 id="分区表的维护">分区表的维护</h3> <p>check table, optimize table, analyze table, and repair table可以被用于维护分区表</p> <p>rebuilding partitions.相当于将分区中的数据drop掉再插入回来,对于避免磁盘碎片很有效<br> example:</p> <pre class="brush:sql;">alter table t1 rebuild partition p0, p1;</pre> <p>optimizing partitions.如果你的表增加删除了大量数据,或者进行了大量的边长列的更新操作( varchar, blob, or text columns)。那么optimize partition将回收未使用的空间,并整理分区数据文件。<br> example:</p> <pre class="brush:sql;">alter table t1 optimize partition p0, p1;</pre> <p>运行optimize partition 相当于做了 check partition, analyze partition, and repair partition</p> <blockquote> <p>some mysql storage engines, including innodb, do not support per-partition optimization; in these cases, alter table … optimize partition rebuilds the entire table. in mysql 5.6.9 and later, running this statement on such a table causes the entire table to rebuilt and analyzed, and an appropriate warning to be issued. (bug #11751825, bug #42822) use alter table … rebuild partition and alter table … analyze partition instead, to avoid this issue.</p> </blockquote> <p>analyzing partitions.读取并保存分区的键分布<br> example:</p> <pre class="brush:sql;">alter table t1 analyze partition p3;</pre> <p>repairing partitions.修补被破坏的分区<br> example:</p> <pre class="brush:sql;">alter table t1 repair partition p0,p1;</pre> <p>checking partitions.可以使用几乎与对非分区表使用check table 相同的方式检查分区。<br> example:</p> <pre class="brush:sql;">alter table trb3 check partition p1;</pre> <p>这个命令可以告诉你表trb3的分区p1中的数据或索引是否已经被破坏。如果发生了这种情况,使用“alter table … repair partition”来修补该分区。</p> <h4 id="以上每个命令都支持将分区换成all">以上每个命令都支持将分区换成all</h4> <blockquote> <p>the use of mysqlcheck and myisamchk is not supported with partitioned tables.</p> </blockquote> <p>mysqlcheck和myisamchk不支持分区表</p> <p>你可以使用 alter table … truncate partition. 来删除一个或多个分区中的数据<br> 如:alter table … truncate partition all删除所有数据</p> <p>analyze, check, optimize, rebuild, repair, and truncate 操作不支持 subpartitions.</p> </enddate>
以上所述是小编给大家介绍的mysql分区表的管理与维护,希望对大家有所帮助