CODEWITHSUNDEEP
mysqlsql
Sridhar DD
Sridhar DD

Reputation: 1980

Will MYSQL update query with non indexed column locks entire table?

I have a table with millions of records.

For simplicity let say table is bank and the schema is below,

bank_id int(Primary Key), bank_name varchar, bank_address varchar.

Now if i run a query

update bank set bank_name=NULL where bank_name='null'

My question here is will my query locks the entire table? or only the records that matches the where condition?

Note: I understand as I am querying with non-indexed column the query will take more time and Its a one time execution so I am not worried much about time taken by the query.

Upvotes: 1

Views: 1492

Answers (1)

Vatev
Vatev

Reputation: 7590

It will lock the entire table.

It locks every row it examines while evaluating the where clause.

Depending on the transaction isolation setting, it may also lock gaps between values, preventing inserts.

Upvotes: 3

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