查看oracle数据库里哪些语句耗时最长或者效率最低

CPU： select * from (select v.sql_id, v.child_number, v.sql_text, v.elapsed_time, v.cpu_time, v.disk_reads, rank() over(order by v.cpu_time desc) elapsed_rank from v$sql v) a where elapsed_rank <= 10; 磁盘： select * from (select v.sql_id, v.child_number, v.sql_text, v.elapsed_time, v.cpu_time, v.disk_reads, rank() over(order by v.disk_reads desc) elapsed_rank from v$sql v) a where elapsed_rank <= 10; 数据库管理员可以执行下述语句来查看SQL语句的解析情况： SELECT * FROM V$SYSSTAT WHERE NAME IN ('parse_time_cpu','parse_time_elapsed','parse_count_ hard'); 这里： ①parse_time_cpu：是系统服务时间。 ②parse_time_elapsed：是响应时间。 而用户等待时间为： waite_time = parse_time_elapsed – parse_time_cpu （2） 数据库管理员还可以通过下述语句，查看低效率的SQL语句： SELECT BUFFER_GETS,EXECUTIONS,SQL_TEXT FROM V$SQLAREA; 优化这些低效率的SQL语句也有助于提高CPU的利用率。 --- 查询每天执行慢的SQL： SELECT S.SQL_TEXT, S.SQL_FULLTEXT, S.SQL_ID, ROUND(ELAPSED_TIME / 1000000 / (CASE WHEN (EXECUTIONS = 0 OR NVL(EXECUTIONS, 1 ) = 1) THEN 1 ELSE EXECUTIONS END), 2) "执行时间'S'", S.EXECUTIONS "执行次数", S.OPTIMIZER_COST "COST", S.SORTS, S.MODULE, --连接模式（JDBC THIN CLIENT：程序） -- S.LOCKED_TOTAL, S.PHYSICAL_READ_BYTES "物理读", -- S.PHYSICAL_READ_REQUESTS "物理读请求", S.PHYSICAL_WRITE_REQUESTS "物理写", -- S.PHYSICAL_WRITE_BYTES "物理写请求", S.ROWS_PROCESSED "返回行数", S.DISK_READS "磁盘读", S.DIRECT_WRITES "直接路径写", S.PARSING_SCHEMA_NAME, S.LAST_ACTIVE_TIME FROM GV$SQLAREA S WHERE ROUND(ELAPSED_TIME / 1000000 / (CASE WHEN (EXECUTIONS = 0 OR NVL(EXECUTIONS, 1 ) = 1) THEN 1 ELSE EXECUTIONS END), 2) > 5 --100 0000微秒=1S AND S.PARSING_SCHEMA_NAME = USER AND TO_CHAR(S.LAST_LOAD_TIME, 'YYYY-MM-DD') = TO_CHAR( SYSDATE, 'YYYY-MM-DD' ) AND S.COMMAND_TYPE IN (2 , 3, 5, 6 , 189) ORDER BY "执行时间'S'" DESC; /* SQL中 COMMAND_TYPE意义: 2：INSERT 3：SELECT 6：UPDATE 7：DELETE 189：MERGE 详情可通过查找V$SQLCOMMAND视图 */ V$SQLAREA 官网解释：http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3064.htm#REFRN30259 V$SQLCOMMAND 官网解释：http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3066.htm#REFRN30632

转载于:https://www.cnblogs.com/chinasui/p/7872712.html