Optimize Mysql update query performance with
Asked By: mohit
Originally Asked On: 2014-01-02 09:50:26
Asked Via: stackoverflow
I have a table in which i need to add a column, The table has millions of record. For existing record i have to update the column value(which will be different for each record). Running individual update query will take lots of time. Is there a way where this can be achieved with minimum amount of locking time for the table.
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All Answers For: Optimize Mysql update query performance with
Nachiket Kate’s answer to
Optimize Mysql update query performance with
in your case there can be two ways,
if your additional column is a derived column (values can be derived from existing columns) then simple update query will be enough
if its not derived one then write all the values in file (probably scripts) and import that file as new column in your table. (or export existing table and modify that file with new column values and then import)
in above two ways, import is faster with less amount of locking.
hope that helps
Joni’s answer to
Optimize Mysql update query performance with
When the hash value cannot be generated in the database, the only thing you can do is run individual updates. You may get some performance improvements by batching several updates into one transaction.
Of course, you should really check out the original question.
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