Number of sort operations that were performed completely in memory and did not require any disk writes You cannot do much better than memory sorts, except maybe no sorts at all. Sorting is usually caused by selection criteria specifications within table join SQL operations. Sorts(disk): 在磁盘...
2).在用start命令执行一个sql脚本时,是否显示脚本中正在执行的SQL语句 SQL> SET ECHO 3).是否显示当前sql语句查询或修改的行数 SQL> SET FEED[BACK] 默认只有结果大于6行时才显示结果的行数。如果set feedback 1 ,则不管查询到多少行都返回。当为off 时,一律不显示查询的行数 4).是否显示列标题 SQL> SET...
SQL>select sid,id1,id2,type,lmode,request from v$lock where sidin(161,189)order by sid;SIDID1ID2TYLMODEREQUEST---161655471930TX60161885390TM30--sid1的表级锁为31611000AE40161798331TO301891966122185TX60189885390TM30--sid2的表级锁为31891000AE40189885390OD60189655471930TX04189798331TO30SQL>select sid,...
Number of sort operations that were performed completely in memory and did not require any disk writes You cannot do much better than memory sorts, except maybe no sorts at all. Sorting is usually caused by selection criteria specifications within table join SQL operations. Sorts(disk): 在磁盘...
高负载SQL语句:是否有任何SQL语句正在消耗过多的系统资源? 高负荷的PL/SQL的执行和编译,和高负荷的java使用? Oracle RAC问题:全局缓存热块和对象是什么;有任何互连延迟的问题? 应用程序最优使用Oracle数据库:如糟糕的连接管理,过度解析析,或应用程序级锁争的问题吗?
ORDER BY 1 This query finds the dates (year and month only) and the employee names that are the same for changes made to thePRODUCTtable and log entries made to thePET_CARE_LOG. The following paragraphs below describe the intersect, union, and minus operations in greater detail. ...
在一个并行服务进程需要做两件事情的时候,它会再启用一个进程来配合当前的进程完成一个工作,比如这样的一条SQL语句: Select * from employees order by last_name; 假设employees表中last_name列上没有索引,并且并行度为4,此时并行协调进程会分配4个并行服务进程对表employees进行全表扫描操作,因为需要对结果集进行...
SQL> alter system set open_cursors=1000 scope=both; 关闭密码过期 --1、查看用户的proifle是哪个,一般是default: (DBSNMP=》MONITORING_PROFILE) SELECT username,PROFILE FROMdba_users; --2、查看指定概要文件(如default)的密码有效期设置: SELECT * FROM dba_profiles s WHERE resource_name='PASSWORD_LIFE...
列表信息v$tablespace表空间信息v$tempfile暂时文件信息v$filestat数据文件的I/O统计信息v$undostatUndo数据信息v$rollname在线回滚段信息v$session会话信息v$transaction事务信息v$rollstat回滚段统计信息v$pwfile_users特权用户信息v$sqlarea当前查询过的sql语句访问过的资源及相关的信息v$sql与v$sqlarea根本一样的相关信息v$...
OracleSQLOracleSQL第一章SELECT查询第一章SELECT查询本章目标写一条SELECT查询语句在查询中使用表达式、运算符对空值的处理对查询字段起别名查询字段的连接本章目标写一条SELECT查询语句SELECT查询基本语法SELECT<列名>FROM<表名>SQL>SELECT*FROMs_emp请查询出s_emp表中所有的员工信息:SELECT查询基本语法SELECT<列名>SQL...