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摘要： Question:What is between between "unique index vs non-unique index". Which one is faster. The customer using non-unique and sql is getting delay If we change tp non-unique. Is it work ?Answer:Indexes ... 阅读全文

摘要： OPROCD introduced in 10.2.0.4 Linux and other Unix platform. Fencing Cluster handling of nodes that should not have access to shared resources STONITH – Power cycle the node PCW – nodes fence themselv... 阅读全文

摘要： Active Session History (ASH) performed an emergency flush. This may mean that ASH is undersized. If emergency flushes are a recurring issue, you may consider increasing ASH size by setting the value o... 阅读全文

摘要： Single resource deadlock: blocking enqueue which blocks itself, f 0Single resource deadlock: blocking enqueue which blocks itself, f 0Granted global enqueue 0xd8578490----------enqueue 0xd8578490-----... 阅读全文

摘要： 在分布式事务环境中数据库的SCN可能瞬间暴增，这种行为被称作SCN jump in distributed transaction，注意这种现象是正常的。在发生分布式事务的2个数据库中，SCN较低的DB会将SCN和较高的那个数据库同步，这有时候会造成我们的一些误解认为可能是Hot backup等操作引起了SCN的猛增。我们来具体看一下这种现象:SQL> select * from v$versio... 阅读全文

摘要： 1. The Total size of the log buffer is determined by LOG_BUFFER parameter.2. Only Server process may pin a data block in exclusive mode.3. LGWR writes to the redo log files when: The redo log buff... 阅读全文

摘要： Scriptset echo offset feedback offcolumn timecol new_value timestampcolumn spool_extension new_value suffixselect to_char(sysdate,'Mondd_hh24mi') timecol,'.out' spool_extension from sys.dual;column ou... 阅读全文

摘要： 通过下图定义的规则，可确定分区索引类型:Hash Global分区索引介绍HASH-Partitioned Global索引是Oracle 10g开始提供的新特性。而在以前的版本中，Oracle只支持Range-Partitioned Global索引。HASH-Partitioned Global索引的好处如下：比Range-Partitioned Global索引易于实施。HASH-Part... 阅读全文

摘要： 以下脚本用于列出Oracle Buffer Cache的详细信息:REM List Buffer Cache DetailsSET LINESIZE 200 PAGESIZE 1400SELECT /*+ ORDERED USE_HASH(o u) MERGE */ DECODE(obj#, NULL, to_char(bh.obj), u.name ||... 阅读全文

摘要： 以下脚本用以列出Database-instance-session的NLS参数和所在时区:REM List NLS Parametersset linesize 90 pagesize 1400col Parameter for a40col Value for a40SELECT Parameter, Value FROM NLS_DATABASE_PARAMETERS/SELECT P... 阅读全文