Maclean’s Oracle Database Tech Blog Archives

在测试ASMlib的时候出现了oracleasm无法创建磁盘的错误，具体如下: [root@vrh1 yum.repos.d]# /etc/init.d/oracleasm configure Configuring the Oracle ASM library driver. This will configure the on-boot properties of the Oracle ASM library driver. The following questions will determine whether the driver is loaded on boot and what permissions it will have. The current values will be shown in brackets (‘[]’). Hitting [ENTER] without typing an…

——————————————————————————- — — Script: rolling_back.sql — Purpose: to predict when transactions will finish rolling back — For: 9.0+ — — Copyright: (c) Ixora Pty Ltd — Author: Steve Adams — ——————————————————————————- @save_sqlplus_settings set serveroutput on set feedback off prompt prompt Looking for transactions that are rolling back … prompt declare cursor tx is select s.username,…

View: X$KTUXE [K]ernel [T]ransaction [U]ndo Transa[x]tion [E]ntry (table) This view is very useful as it gives an indication of the state of the transaction tables in the rollback segment headers. The information here can be used to see the state of transactions requiring transaction recovery do not show in <View:V$TRANSACTION> <Event:10013> may be useful to…

Error: ORA 10500 Text: turn on traces for SMON ——————————————————————————- Cause: Action: Level: <=5 trace instance recovery > 5 trace posting of SMON To set event 10500: For the instance: a. Shutdown database b. Edit the initialisation parameter file and add: event=”10500 trace name context forever, level <value>” c. restart the database For the SMON…

What is skip scanning?   In prior releases, a composite index would be used to retrieve the records, if the index prefix (leading) column was included in the predicate of the statement. With Oracle9i, the optimizer can use a composite index even if the prefix column value is not known. The optimizer uses an algorithm…

The change vectors as constructed by the transaction layer are used by the cache layer to apply the physical block changes. Redo log ordering and recovery as well as read consistency are the fundamental purposes of SCNs. The change vector: Change vectors are built in the PGA process of the process modifying a block, have…

Event:10211                  See <Note:32969.1> for similar events / parameters ~~~~~~~~~~~                     Version/Use:   7.0 – 8.1.7  Check data block integrity after each modification   9.0+         This event is no longer valid. Use <Parameter:DB_BLOCK_CHECKING>                 instead. 7.0 – 8.1.7 “Check data block integrity after each modification” ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~   NOTE: Events should NEVER be set by customers unless…

Event:10060 Text:   dump predicates in optimizer (kko) ——————————————————————————- Explanation:         This is a special EVENT code.         It should *NOT* be used unless explicitly requested by ST support.         This event can be useful in conjunction with an explain plan         to confirm which operations occur where in the execution plan.         It dumps the…

@23-JAN-01, rpowell.uk, Distribution justification: “Should not be used by @ customers unless told to by support so making noncustomer-viewable.” – dbither.us Event: 10218 Text:  dump uba of applied undo ——————————————————————————- Note:    Events should NEVER be set by customers unless advised to do so by    Oracle Support Services.  See <Note:75713.1> for more details. Description:…

Error: ORA 10226 Text: trace CR applications of undo for data operations ——————————————————————————- Explanation: This is NOT an error but is a special EVENT code. It can be used to signal Oracle to perform SQL_TRACE actions. This event causes application of UNDO for producing CR copies of blocks. It can produce a lot of output…