How to avoid “ORA-00932: inconsistent datatypes: expected – got CLOB” when distinct CLOB datatypes.
Large objects (LOBs) are not supported in comparison conditions. However, you can use PL/SQL programs for comparisons on CLOB data.
skgpspawn failed:category = 27143 in alert log
skgpspawn failed:category = 27143, depinfo = 24, op = pipe, loc = skgpspawn2
…
oracle 12c new feature 隐藏列(invisible columns)
oracle 12c release 1版本引入新功能可隐藏列(invisible columns),这个特性有很多的争议，不明白为什么ORACLE会推出这个特性，因为这个特性可能会带来很多麻烦..
Adaptive Cursor Sharing in 11R2 performance issues(自适应游标共享问题案例)
今天开发的同事找我说是一个报表系统的SQL执行第一次很快，再执行就慢的几乎查询无响应，找他要来了SQL，也是常见的表关连LIFT JOIN 、GROUP BY的统计报表, 出于篇幅原因不再贴SQL， 把SQL放到TOAD 中问题依然可以再现，..
Adaptive Log File Sync In 11gr2 (_use_adaptive_log_file_sync)
Adaptive Log File sync was introduced in 11.2. the feat […]
How to enable SQL*Net Tracing with Oracle Instant Client 11G
Sometimes we need to enable sql*net trace to diagnose sqlplus connection problems such as ora-125*
Below are the steps to configure Sql*Net verbose Client side tracing:
How to get call stack of oracle processes ?
Each time your program performs a function call, information about the call is generated. That information includes the location of the call in your program, the arguments of the call, and the local variables ..
Script: Display the sessions distribution and top 50 idle sessions
This script displays the top 50 longest idle times and list distribution of sessions on the instance..
I prefer the version 11.2.0.3 parse_calls (我比较喜欢parse_calls在11203版本上的显示)
高parse calls表示这些SQL不可以re-used 并且每次执行都要重新解析，理想的最佳状态是一次解析多次执行，你也知道频繁的解析会给library cache带来沉重的负担， 一个sql的执行必须先parse，解析过程包含sql 加载到shared pool, 语法检查…
Logon Storms on 11g ,audit maybe cause performance issue.(当创建很多连接时审计可能带来性能问题)
When multiple connection created will insert a lot of rows in aud$ table, there may be contention in the segment header for the table. This contention can manifest itself as a buffer busy wait or a freelist wait.
Unable to change MEMORY_MAX_TARGET (无法修改MEMORY_MAX_TARGET)
alter system set memory_max_target=0 scope=spfile;
shutdown immediate
startup
SQL> show parameter target
…
memory_max_target big integer 3824M
Logon Storm and Memory shortage issue ORA-07445 dbgtrReserveSpace (记录一次登录风暴致内存不足的问题)
Exception [type: SIGSEGV, Address not mapped to object] [ADDR:0x10] [PC:0x938E8C5, dbgtrReserveSpace()+99] [flags: 0x0, count: 1]
Errors in file /oracle/diag/rdbms/ora11g/ora11g/trace/ora11g_ora_13864.trc (incident=60801):
ORA-07445: exception encountered: core dump [dbgtrReserveSpace()+99] [SIGSEGV] [ADDR:0x10] [PC:0x938E8C5] [Address not mapped to object] []
Incident details in: /oracle/diag/rdbms/ora11g/ora11g/incident/incdir_60801/ora11g_ora_13864_i60801.trc
Use ADRCI or Support Workbench to package the incident.
scn format (scn格式)
scn(system change number) 结构主要维护 oracle数据库内部的数据一致性，SCN 有两部分组成: Base and wrap，wrap 是16bit的数字，base是32bit的数字,这样其实就可以算scn的有效范围，它的格式(redo dump trace)是wrap.base，当base超过了2的32次方,然后wrap 就会加1，其实用sql 很好验证。
SQL Test Case Builder generate test case automatically(自动生成SQL所需测试数据)
Why SQL Test Case Builder? For most SQL problems, the s […]
ORA-00313,ORA-00312,ORA-27037,ORA-19527 DATAGARD 11G r2
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
DDE: Problem Key ‘ORA 312’ was flood controlled (0x5) (no incident)
ORA-00312: online log 2 thread 1: ‘/oracle/oradata/icme/redo02.log’
Error 19527 creating/clearing online redo logfile 2
Send email using utl_smtp in Oracle 11g (results in ORA-24247)(11g ACL 网络访问控制列表)
ORA-24247: network access denied by access control list (ACL)
ORA-06512: at “SYS.UTL_TCP”, line 17
ORA-06512: at “SYS.UTL_TCP”, line 267
Oradebug Security
DEMO 1,How to use oradebug to call OS commands via the database
DEMO 2,Disable sys audit
How to imp job to another schema in same db(同一数据库导入JOB到另外一用户)
ORA-39083: Object type JOB failed to create with error:
ORA-00001: unique constraint (SYS.I_JOB_JOB) violated
Dynamically Changing shared_pool_size fail!(动态修改Shared pool size失败)
因安装数据库时启用了ASMM,过了几天发现分配不太理想想禁用ASMM，手动调整shared_pool_size, 这是一个动态参数，修改后立即生效无需重启数据库实例，但修改时遇到了比较奇怪的现象。
ORA-07445 [kggchk()+77] [SIGSEGV] [Address not mapped to object]
今天有个项目系统负载突然变大，查到top sql是一个存储过程,执行计划缺少合理的索引，SQL是个update […]
