How to do it
Select the table you want to maintain, then click either
Optimize Table, Analyze Table, Check Table or Repair Table
from the Table menu to start the operation. Navicat will show
all the resulting output of the operation.
NOTE: Navicat maintains
the tables by issuing standard OPTIMIZE TABLE, CHECK TABLE,
ANALYZE TABLE and REPAIR TABLE statements to the MySQL server.
This is not supported in all versions of MySQL and is only
applicable to MyISAM table types at this moment. Please refer
to the MySQL documentations for more details on the isamchk
and myisamchk command line utilities.
Optimize tables
The main reason for optimizing your table is to reclaim unused
space in the table. You should optimize a table if you have
deleted a large part of a table or if you have made many changes
to a table with variable-length rows (tables that have VARCHAR,
BLOB, or TEXT columns). Deleted records are maintained in
a linked list and subsequent INSERT operations reuse old record
positions.
Check tables
Check the table(s) for errors and update the key statistics
for the table. The operation will have the following output:
| Column |
Value |
| Table |
Table name. |
| Op |
Always "check". |
| Msg type |
One of status, error, info, or warning. |
| Msg text |
The message. |
Note that you can get many rows of information for each
checked table. The last row will be of Msg_type status and
should normally be OK. If you don't get OK, or Not checked
you should normally run a repair of the table. Not checked
means that the table the given TYPE told MySQL that there
wasn't any need to check the table. The different check types
stand for the following:
| Type |
Meaning |
| QUICK |
Don't scan the rows to check for wrong links. |
| FAST |
Only check tables which haven't been closed properly. |
| CHANGED |
Only check tables which have been changed since last
check or haven't been closed properly. |
| EXTENDED |
Do a full key lookup for all keys for each row. This
ensures that the table is 100 % consistent, but will take
a long time! |
Analyze tables
Analyze and store the key distribution for the table. During
the analyze the table is locked with a read lock. This is
equivalent of running myisamchk -a on the table. MySQL uses
the stored key distribution to decide in which order tables
should be joined when one does a join on something else than
a constant.
The command returns a table with the following columns:
| Column |
Value |
| Table |
Table name. |
| Op |
Always "analyze" |
| Msg type |
One of status, error, info, or warning. |
| Msg text |
The message. |
You can check the stored key distribution with the SHOW
INDEX command. If the table hasn't changed since the last
ANALYZE TABLE command, the table will not be analyzed again.
Repair tables
Repair the corrupted table. The operation returns a table
with the following columns:
| Column |
Value |
| Table |
Table name. |
| Op |
Always "repair" |
| Msg type |
One of status, error, info, or warning. |
| Msg text |
The message. |
Note that you can get many rows of information for each repaired
table. The last one row will be of Msg type status and should
normally be OK. If you don't get OK, you should try repairing
the table with myisamchk -o, as REPAIR TABLE does not yet
implement all the options of myisamchk. In the near future,
we will make it more exible.
If you use QUICK then MySQL will try to do a repair of only
the index tree.
If you use EXTENDED then MySQL will create the index row
by row instead of creating one index at a time with sorting;
This may be better than sorting on fixed length keys if you
have long char() keys that compress very good.
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