SQL语句执行结束后,会调用函数 TimingIterator<RealIterator>::TimingString 打印算子执行耗时信息,调用堆栈信息如下表所示: dispatch_command mysql_parse mysql_execute_command Sql_cmd_dml::execute Sql_cmd_dml::execute_inner explain_query ExplainI
The EXPLAIN command will fail if you use it for other SQL commands, such as data definition language (DDL) or database operations. The EXPLAIN output relative unit costs are used by Amazon Redshift to choose a query plan. Amazon Redshift compares the sizes of various resource estimates to ...
SQL语句执行结束后,会调用函数TimingIterator<RealIterator>::TimingString打印算子执行耗时信息,调用堆栈信息如下表所示: dispatch_command mysql_parse mysql_execute_command Sql_cmd_dml::execute Sql_cmd_dml::execute_inner explain_query ExplainIterator PrintQueryPlan ExplainAccessPath TimingIterator<RealIterator>:...
做一个完美的程序猿 2017-10-30 08:01 explain • explain是解释SQL语句的执行计划,即显示该SQL语句怎么执行的 ◦ 使用 explain 的时候,也可以使用 desc • 5.6 版本支持DML语句进行explain解释 • 5.6 版本开始支持 JSON格式 的 注意:EXPLAIN查看的是执行计划,做SQL解析,不会去真的执行;且...SQL...
ERROR: cannot execute create_hypertable() in a read-only transaction 52 changes: 52 additions & 0 deletions 52 tsl/test/sql/read_only.sql Original file line numberDiff line numberDiff line change @@ -12,8 +12,59 @@ -- CREATE TABLE test_table(time bigint NOT NULL, device int); -...
Parameter Value : SQLC2H21 Parameter Name : SOURCE_SCHEMA Parameter Value : NULLID Parameter Name : SOURCE_VERSION Parameter Value : You can now examine the explain information, either by examining the explain tables using SQL, or using thedb2exfmtcommand to format the inform...
Action: Refresh the materialized view or alter the rewrite integrity mode with ALTER SESSION QUERY_REWRITE_INTEGRITY = STALE TOLERATED command. QSM-01030 materialized view, string, has PL/SQL functions in ENFORCED integrity mode Cause: A materialized view with PL/SQL functions in its definition cann...
Description: The assert happens in sql_error.cc:360 : void Diagnostics_area::set_ok_status(THD *thd, ulonglong affected_rows_arg, ulonglong last_insert_id_arg, const char *message_arg) { DBUG_ENTER("set_ok_status"); DBUG_ASSERT(! is_set()); <--- /* In production, refuse to ...
These are the methods under Command Object ExecuteReader : Used to execute SQL Select Command ExecuteScalar : Used to execute SQL Select command which is used to return a single value. Example the group function output ExecuteNonQuery : USed to execute SQL Insert, Delete and Update Commands. ...
SQL:Structured Query Language used to manipulate the data with help of queries. The SQL uses some operators to throw queries like SELECT uses to selects a data value and shown on the output screen, Where uses for conditions, Group by use...