Shulou(Shulou.com)06/01 Report--

1: physical analysis of test environment and formal environment, do not open both test maintenance window and production window

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OS operation

1:rm

A famous "murder of a blank"

-rm-rf / usr/lib/nvidia-current/xorg/xorg + rm-rf / usr/lib/nvidia-current/xorg/xorg

How to avoid: using mv instead of rm to get to the temporary position first

But mv also has a serious problem: if you move a file to an existing target file, the contents of the target file will be overwritten.

Solution mv-I dsw.ora / home/oracle/

This problem also exists in cp-a. Be sure to check whether the target directory has a file with the same name before cp.

Do not write after rm *

2:chmod 755-R / home/oracle

It is also a problem of spaces. To modify permissions, chmod chown must also check whether the file directory is overwritten with spaces.

Decompress 3:tar. If an object with the same name exists, it will be overwritten.

[root@parnassusdata1 ] # lsa1 a2a3 d.tar [root@parnassusdata1 ] # cat a1555555555555555555555558888 [root@parnassusdata1 ] # tar xvf d.tar a1a2a3 [root@parnassusdata1 ] # cat a18888

4: execute the script, be sure to check, the name of the script with log and description

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DB operation

1:dml 's update delete lost where condition

Drop and truncate in 2:ddl are backed up before operation.

3: do not perform ddl during peak business hours

(1) ddl causes a series of database chain reactions such as SQL reparsing and dependent object (procedure) invalidation. Once SQL reparsing occurs, the system

The system is bound to experience a peak load, and if the system is busy, it may hang up.

(2) any change in ddl requires check, an object that may be referenced.

4: carefully collect statistics and create indexes

(1) alter index rebuild online (big watch with caution)

Online failed, and smon was still cleaning up the temporary period during the peak of business during the day, resulting in traffic jams.

5: prevent index failure: index failure caused by partition maintenance

6: forgot to turn off trace disk occupancy resulting in system hang

Use alter system-level tracing with caution

7:kill-9 must confirm that do not kill the background process.

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