SQL>showparametershared_pool NAMETYPEVALUE --- --- --- shared_pool_sizebiginteger41943040 SQL>select*fromv$sga_dynamic_free_memory; CURRENT_SIZE --- 8388608 1.1.3.数据库缓冲区(Database Buffers) Buffer Cache是SGA区中专门用于存放从数据文件中读取的的数据块拷贝的区域。Oracle进程如果发现需要访问的...
概念2:逻辑读指的就是从Buffer Cache中读取数据块。按照访问数据块的模式不同,可以分为当前模式读(Current Read)和一致性读(Consistent Read)。 这两个概念本质是一样的,只是措辞不一样。 一致性读(Consistant Get) ORACLE是一个多用户系统。当一个会话开始读取数据还未结束读取之前,可能会有其他会话修改了它将...
一文搞懂Oracle锁相关视图及相关操作 本文主要研究锁的相关视图,以及锁的相关操作,通过视图查锁的问题。 一、v$transaction视图 第一个视图是v$transaction,就是Oracle数据库所有活动的事务数,所有活动的事务每一个活动的事务在这里有一行。 v$transaction XIDUSN表示当前事务使用的回滚段的编号 XIDSLOT说明该事务在回滚...
sequence#, a.status, a.archived, a.bytes / 1024 / 1024 size_mb from v$log a ,v$logfile b where a.group# = b.group# order by 1,2; #查看表空间是不是自动扩展 select tablespace_name,AUTOEXTENSIBLE,INCREMENT_BY from dba_data_files; #设置自动扩展 alter database datafile '/u01/app/...
ORA-17160 execution context id sequence number out of range 执行上下文 ID 序列号超出范围。 ORA-17161 Invalid transaction mode used 使用的交易模式无效。 ORA-17162 Unsupported holdability value 不支持的 holdability 值。 ORA-17163 Can not use getXAConnection() when connection caching is enabled 无法在...
The installer installs the files in the proper system directories, regardless of the value you enter in this field. Click Next. 3. Warning: System Reboot If you see this screen, the installer will reboot your computer automatically at the Required end of this installation to complete the ...
In Oracle Database 10gRelease 2 (10.2) theCONNECTrole only contains theCREATE SESSIONprivilege. Making this change enables new and existing database customers to enforce good security practices more easily. Applications that rely on theCONNECTrole to create tables, views, sequences, synonyms, cluster...
再看一个sql语句 select name,value from v$parameter where name in(‘transactions’,’dml_locks’); 可以获得的TX锁定的总个数由初始化参数transactions决定,而可以获得的TM锁定的个数则由初始化参数dml_locks决定 transactions参数表示Oracle一个实例最多可有的事务数 ...
Current status: In recovery[1]: At EOF Current read position: Sequence #: 24 RBA: 6921352 Timestamp: 2011-11-17 20:17:20.000000 Current write position: Sequence #: 0 RBA: 0 Timestamp: 2011-11-17 16:56:31.777616 Extract Trail: /u01/ggate/dirdat/lt ...
Step 1 – change nth_value() to the appropriate first/last. Step 2 – get rid of the “from last” which won’t be needed with last_value() Step 3 – move the “ignore nulls” to the spot that Oracle wants to see it with first/last Here’s the resulting SQL – I’ve left th...