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Oracle 11g 针对SQL性能的新特性（三）- SQL Plan Management
【源自网络】SQL Plan Management (SPM)历史SQL的执行效率，取决于它的执行计划是否高效。 优化器的算法是一个平衡，需要收集尽量少的信息，用尽量快的速度试图去得到一个最优的执行计划，这也决...
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rollback的进度
【源自网络】如果一个会话正在回滚，如何知道回滚的进度？如何知道还需要多长时间才能回滚结束？下面做一个简单的总结：=========================一、对于死事务对死事务，可以查询x$ktuxe: [K]er...
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CheckPoint
【源自网络】 目的-----本文帮助DBA更好地理解增量检查点，checkpoint调优的相关参数信息： - FAST_START_MTTR_TARGET - LOG_CHECKPOINT_INTERVAL - LOG_CHECKPOIN...
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权限视图
ALL_COL_PRIVSDescribes all column object grants for which the current user or PUBLIC is the object owner, grantor, or granteeALL_COL_PRIVS_MADELists column object grants for which ...
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monitor impdp/expdp
相关视图：• DBA_DATAPUMP_JOBS - all active Data Pump jobs and the state of each job • USER_DATAPUMP_JOBS – summary of the user’s active Data Pump jobs • DBA_DATAPUMP_SESSIO...
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Creating Physical Standby Using RMAN DUPLICATE FROM ACTIVE DATABASE
Applies to: Oracle Server - Enterprise Edition - Version 11.1.0.6 to 11.2.0.4 [Release 11.1 to 11.2]Information in this document applies to any platform.GoalStep by step guide on how to creat...
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ORA-32000 not able to modify the rdbms spfile which is there in ASM
In this DocumentSymptomsChangesCauseSolutionApplies to: Oracle Server - Enterprise Edition - Version 11.2.0.1 and laterInformation in this document applies to any platform.SymptomsNot able to...
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Oracle IO问题解析
【源自网络】数据库的作用就是实现对数据的管理和查询。任何一个数据库系统，必然存在对数据的大量读或者写或者两中操作都大量存在。IO问题也往往是导致数据库性能问题的重要原因。在这篇文章中，主要帮助大...
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视图杂记8
V$SESSION_BLOCKERSV$SESS_TIME_MODELV$SYS_TIME_MODEL V$SESSION_LONGOPSV$SESSION_WAIT_HISTORYV$SESSION_CONNECT_INFOV$LOCKED_OBJECTDBA_HIST_SNAPSHOTDBA_HIST_SQLSTATV$ARCHIVE_PROCESSESV$ASM_DISK_S...
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SESSION_CACHED_CURSORS，OPEN_CURSORS，CURSOR_SHARING
SESSION_CACHED_CURSORS,就是说的是一个session可以缓存多少个cursor，让后续相同的SQL语句不再打开游标,从而避免软解析的过程来提高性能。(绑定变量是解决硬解析的问题)，软解析同硬解析一样,比较消耗资源....
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缩小表空间，回收磁盘
##缩小表空间select /*+ ordered use_hash(a,c) */ &nb...
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How To Analyze the Wait Statistic: 'enq: HW - contention' [ID 419348.1]
In this Document Goal SolutionApplies to: Oracle Server - Enterprise Edition - Version: 10.2.0.1 and later [Release: 10.2 and later ]Information in this document applies to any plat...
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Wait: log file sync
When a user session commits (or rolls back), the session's redo information must be flushed to the redo logfile by the LGWR background process. This event shows the time that it takes for th...
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Automatic SQL Tuning - SQL Profiles. [ID 271196.1]
Applies to: Oracle Server - Enterprise Edition - Version 10.1.0.2 and laterInformation in this document applies to any platform.PurposeSQL Profiles is a new feature from 10g which is manage...
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ORACLE监听日志的正确删除步骤
【源自网络】1.进入$ORACLE_HOME/network/log,查看日志大小 du -a2. 把 listen log 关闭.lsnrctl set log_status off;3.把日志改名,mv listener.log listener.log_bak4.启动listen log lsnrctl set log_s...
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视图杂记7
ALL_AUDIT_POLICIESALL_AUDIT_POLICY_COLUMNS ALL_CLUSTERSALL_COLL_TYPESALL_COL_COMMENTSALL_COL_PENDING_STATSALL_COL_PRIVS ALL_COL_PRIVS_MADEALL_COL_PRIVS_RECD ALL_CONSTRAINTSALL_CONS_C...
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视图杂记5
•DBA_TABLES and DBA_OBJECT_TABLES•DBA_TAB_STATISTICS and DBA_TAB_COL_STATISTICS•DBA_TAB_HISTOGRAMS•DBA_TAB_COLS•DBA_COL_GROUP_COLUMNS•DBA_INDEXES and DBA_IN...
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视图杂记4
When you specify WITHOUT VALIDATION for the exchange partition operation, this is normally a fast operation because it involves only data dictionary updatesTo avoid the overhead of this valida...
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视图杂记3
DBA_CONSTRAINTS ALL_CONSTRAINTSUSER_CONSTRAINTS DBA view describes all constraint definitions in the database. ALL view describes constraint definitions accessible to current user. USER v...
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视图杂记2
SELECT * FROM V$DIAG_CRITICAL_ERROR;---To find the trace file for your current session:SELECT VALUE FROM V$DIAG_INFO WHERE NAME = 'Default Trace File';---To find all trace files for the curren...
