Mysql myisamchk fixes Common Database Command records

If a problem occurs in the database or data table in mysql, we can use the myisamchk command to modify it. Next I will introduce the usage of the myisamchk command.

Instance

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# Locate myisamchk # Ln-s/usr/local/mysql/bin/myisamchk/usr/bin/myisamchk # Myisamchk tablename. MYI # Myisamchk-r-q tablename

If-r doesn't work, execute the following command forcibly:

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# Myisamchk-r-o-f

Now, let's share an instance.

MyISAM is the default storage engine. MyISAM table of MySQL ).
This article will teach you how to check/repair? What kind of information can I do if I'm a camgirl? YISAM tables.

Every time you go to MySQL DB? Create a table, which will be stored in the file system at the same time? Create files in three formats: *. frm, *. MYD, and *. MYI.

*. Frm = file to store table format)
*. MYD (MyData) = used to store data (file to store data)
*. MYI (MyIndex) = used to store the index (file to store index)

How to check the database? Which table needs to be repaired? Stop? /P>

Run the following command with root: Check the tables in DB1

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# Myisamchk/var/lib/mysql/DB1/*. MYI & gt;/tmp/myisamchk. log

In the screen output, if the following words are found, the data table should be repaired ?? /P>

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Myisamchk: error: Keypointers and record positions doesn't match MyISAM-table '/var/lib/mysql/DB1/news_post_comment.myi' is already upted Fix it using switch "-r" or "-o" Myisamchk: warning: 1 client is using or hasn' t closed the table properly MyISAM-table '/var/lib/mysql/DB1/news_post.myi' is usable but shoshould be fixed Myisamchk: warning: 1 client is using or hasn' t closed the table properly MyISAM-table '/var/lib/mysql/DB1/news_post_push_log.myi' is usable but shoshould be fixed

More information is displayed in the Redirect File. As follows:

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Checking MyISAM file:/var/lib/mysql/DB1/yam_bbauth.MYI Data records: 14 Deleted blocks: 0 -Check file-size -Check record delete-chain -Check key delete-chain -Check index reference -Check data record references index: 1 -Check record links

How to Use myisamchk for repair? Tu Meizhen? Ables:

Run the following command to repair the corrupted table? Stop? /P>

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# Myisamchk-r/var/lib/mysql/DB1/news_post_comment.MYI -Recovering (with sort) MyISAM-table '/var/lib/mysql/DB1/news_post_comment.MYI Data records: 1 -Fixing index 1

If the table is being used by an application, you may see that clients are using or haven'tclosed the table properly.
So it is recommended to repair? Too many? Disable ysqld or use flush tables to lock TABLES to prevent repair? Shadow? Pplication changes the database TABLE.

How to check and repair? Tun? Benzene? School? /P>

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# Myisamchk -- silent -- force -- fast -- update-state/var/lib/mysql/DB1/*. MYI Myisamchk: MyISAM file/var/lib/mysql/DB1/groups. MYI Myisamchk: warning: 1 client is using or hasn' t closed the table properly Myisamchk: MyISAM file/var/lib/mysql/DB1/profiles. MYI Myisamchk: warning: 1 client is using or hasn' t closed the table properly

The meaning of options is as follows:
? S,-silent option: Prints only errors. You can use two-s to make myisamchk very silent.
? -F,-force option: Restart myisamchk automatically with repair option-r, if there are any errors in the table.
? -F,-fast option: Check only tables that haven'tbeen closed properly.
? -U-update-state option: Marks tables as crashed, when it finds any error.

Repair? Fading? Are there any other problems? Yo? B

Large table, repair? Token? Why? Are you sure you want to continue? Why ?? /P>

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# Myisamchk -- silent -- force -- fast -- update-state -- key_buffer_size = 512 M -- sort_buffer_size = 512 M -- Read_buffer_size = 4 M -- write_buffer_size = 4 M/var/lib/mysql/DB1/*. MYI

Use myisamchk to obtain table information

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# Myisamchk-dvv profiles. MYI MyISAM file: profiles. MYI Record format: Packed Character set: latin1_swedish_ci (8) File-version: 1 Creation time: 2007-08-16 18:46:59 Status: open, changed, analyzed, optimized keys, sorted index pages Auto increment key: 1 Last value: 88 Data records: 88 Deleted blocks: 0 Datafile parts: 118 Deleted data: 0 Datafile pointer (bytes): 4 Keyfile pointer (bytes): 4 Datafile length: 6292 Keyfile length: 6144 Max datafile length: 4294967294 Max keyfile length: 4398046510079 Recordlength: 2124 Table description: Key Start Len Index Type Rec/key Root Blocksize 1 2 3 unique int24 1 1024 1024 2 5 765 unique char packed stripped 1 2048 4096 Field Start Length Nullpos Nullbit Type