在Oracle Data Guard环境中,一个备库出现问题,需要重做。因为之前的配置环境都是好的,只需将主库的全库备份恢复到备库即可。但
在Oracle Data Guard环境中,一个备库出现问题,需要重做。因为之前的配置环境都是好的,只需将主库的全库备份恢复到备库即可。但在数据文件还原完成后,介质恢复时在alert.log中提示有gap的日志文件,RFS进程继续去提取主库上的其他的归档日志文件。
alert.log文件中提示信息如下:
TueApr 9 14:20:56 2013
MediaRecovery Log +LOGDG/servdg2/archivelog/2013_04_09/thread_1_seq_71989.3551.812298053
MediaRecovery Waiting for thread 2 sequence 68042
Fetchinggap sequence in thread 2, gap sequence 68042-68094
TueApr 9 14:20:58 2013
RFS[1]:Archived Log:
'+LOGDG/servdg2/archivelog/2013_04_09/thread_2_seq_68052.2968.812298059'
TueApr 9 14:21:31 2013
Fetchinggap sequence in thread 2, gap sequence 68042-68051
TueApr 9 14:22:06 2013
FAL[client]:Failed to request gap sequence
GAP - thread 2 sequence 68042-68051
DBID 3658273059 branch 717104091
FAL[client]:All defined FAL servers have been attempted.
-------------------------------------------------------------
Check thatthe CONTROL_FILE_RECORD_KEEP_TIME initialization
parameteris defined to a value that is sufficiently large
enough tomaintain adequate log switch information to resolve
archiveloggaps.
-------------------------------------------------------------
备库因日志中断而不能继续进行介质恢复。我们的问题就是如何将这些日志文件找回来。
在主库中,判断归档日志状况。
select *from v$archived_log b where b.SEQUENCE#>=68042 and b.THREAD#=2 andb.SEQUENCE#
通过这个SQL,确认这些归档日志已经被删除了。
归档日志文件通过RMAN工具定期删除的,因为还原数据文件过程很长,在还原完成后,归档日志已经备份移走了。
RMAN>list backup of archivelog from sequence 68042 until sequence 68051 thread 2;
在rman备份集中找到结果集,使用restore archivelog还原。
RMAN>restore archivelog from sequence 68042 until sequence 68051 thread 2;
这样,备库上又能继续获取这些归档日志文件了。如果没有,在主库上将指向该备库的log_archive_dest_state_*先defer再enable一下,算是激活这个服务。
因为主库是RAC的,所以会有多个实例会提示这种错误,依次解决即可。

MySQLhandlesconcurrencyusingamixofrow-levelandtable-levellocking,primarilythroughInnoDB'srow-levellocking.ComparedtootherRDBMS,MySQL'sapproachisefficientformanyusecasesbutmayfacechallengeswithdeadlocksandlacksadvancedfeatureslikePostgreSQL'sSerializa

MySQLhandlestransactionseffectivelyusingtheInnoDBengine,supportingACIDpropertiessimilartoPostgreSQLandOracle.1)MySQLusesREPEATABLEREADasthedefaultisolationlevel,whichcanbeadjustedtoREADCOMMITTEDforhigh-trafficscenarios.2)Itoptimizesperformancewithabu

MySQLisbetterforspeedandsimplicity,suitableforwebapplications;PostgreSQLexcelsincomplexdatascenarioswithrobustfeatures.MySQLisidealforquickprojectsandread-heavytasks,whilePostgreSQLispreferredforapplicationsrequiringstrictdataintegrityandadvancedSQLf

MySQL processes data replication through three modes: asynchronous, semi-synchronous and group replication. 1) Asynchronous replication performance is high but data may be lost. 2) Semi-synchronous replication improves data security but increases latency. 3) Group replication supports multi-master replication and failover, suitable for high availability requirements.

The EXPLAIN statement can be used to analyze and improve SQL query performance. 1. Execute the EXPLAIN statement to view the query plan. 2. Analyze the output results, pay attention to access type, index usage and JOIN order. 3. Create or adjust indexes based on the analysis results, optimize JOIN operations, and avoid full table scanning to improve query efficiency.

Using mysqldump for logical backup and MySQLEnterpriseBackup for hot backup are effective ways to back up MySQL databases. 1. Use mysqldump to back up the database: mysqldump-uroot-pmydatabase>mydatabase_backup.sql. 2. Use MySQLEnterpriseBackup for hot backup: mysqlbackup--user=root-password=password--backup-dir=/path/to/backupbackup. When recovering, use the corresponding life

The main reasons for slow MySQL query include missing or improper use of indexes, query complexity, excessive data volume and insufficient hardware resources. Optimization suggestions include: 1. Create appropriate indexes; 2. Optimize query statements; 3. Use table partitioning technology; 4. Appropriately upgrade hardware.

MySQL view is a virtual table based on SQL query results and does not store data. 1) Views simplify complex queries, 2) Enhance data security, and 3) Maintain data consistency. Views are stored queries in databases that can be used like tables, but data is generated dynamically.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

MantisBT
Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

EditPlus Chinese cracked version
Small size, syntax highlighting, does not support code prompt function

SublimeText3 Chinese version
Chinese version, very easy to use

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment

SecLists
SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.
