Re: Locking concurrency: select for update vs update

Hello,

I have two tables phone_number and phone_number_type

When I start transaction and insert phone_number using FK from phone_number_type. Then I can during another TX update row from phone_number_type, but I can't execute select for update on it.

In db stats I see during inserInto AccessShareLock, during update RowExclusieLock but during select for update AccessExclusieLock.

Why I can't execute 'select for update' but I can update???? We often use 'select for update' to avoid update the same record in differents TX but I don't understand why this block another tx from using this record as FK


Best regards
Mirek


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