1. 解释"mysql state creating sort index"的含义 在MySQL中,state creating sort index表示当前线程正在处理一个SELECT语句,这个SELECT语句需要通过创建一个内部临时表来进行排序操作。这通常发生在ORDER BY子句没有利用索引进行排序,需要执行filesort操作的情况下。filesort是MySQL对查询结果进行排
1, limit a,b 在a值过大时,也会导致性能严重下降,解决方案是获取到一批数据之后拿到最大的ID,然后在查询条件中加入>该ID 这样只需要limit一次获取的数量即可 2,条件更新时,如果数据量过大,先使用该条件进行查询得到要修改的列主键,再以主键为条件进行更新条件能提高性能...
Aurora MySQL version 2 up to 2.09.2 Context Thecreating sort indexstate appears when a query with anORDER BYorGROUP BYclause can't use an existing index to perform the operation. In this case, MySQL needs to perform a more expensivefilesortoperation. This operation is typically performed in...
My problem is the "Creating sort index 0.473379" in the first query execution. A lot of my queries go up to 20 seconds, only because of the "ORDER BY" part in the query. I can't believe is cost half a second to sort 6000 rows… As it is a bulletin board with thousands of use...
Description:excute query statements: select *from t1 where task_statu=0 order by create_time result: There is no suitable result , no rows return use profiling find “Creating sort index” i think this a bug; when no data have ,profiling no have "Creating sort index"How to repeat:mysql>...
SHOW FIELDS是SHOW COLUMNS一个同义词,SHOW KEYS是SHOW INDEX一个同义词。你也可以用mysqlshow db_name tbl_name或mysqlshow -k db_name tbl_name 列出一张表的列或索引。 SHOW INDEX以非常相似于ODBC的SQLStatistics调用的格式返回索引信息。下面的列被返回: ...
mysql版本:5.6 先用optimize table 试试。 也执行了很久。但是结束后,data_free 没有变化。 再用alter table table_name force。 也等了很久,回来一看,居然报错了:Creating index 'PRIMARY' required more than 'innodb_online_alter_log_max_size' bytes of modification log. Please try again ...
该参数是MySQL5.6.6新加入的一个参数,用以指定对InnoDB表做在线DDL操作时所使用的临时日志文件的最大大小(以字节为单位,默认128M)。在创建索引或者ALTER表时会使用该临时文件。该文件记录了DDL操作期间插入、更新、删除的数据。在必要的时候该日志文件的大小会根据innodb_sort_buffer_size的值增加容量直至达到innodb_...
mysql tables in use 5, locked 5 1715 lock struct(s), heap size 210472, 33507 row lock(s) MySQL thread id 3374206, OS thread handle 0x7f699e75b700, query id 118652327 testdb x.x.x.x user1 Creating sort index SET @var_tmp_start_date = ...
I am running on MYSQL SERVER 5.6.15 and when select from a table with 100k row with sorting and limit as query below, there have a process of creating sort index which is very slow around 20 seconds for the first time and around 5 seconds for the second time. It only happen to myis...