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Message Posted: Wed, 18 Feb 2009 @ 17:53:15 GMT


     
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Subj:   Views and locking
 
From:   craig_wilson

Hi All,

We have several sets of views that we access our data through, to control access etc, and all have 'locking row for access' modified before the select. We added this modifier to allow reading and writing to the same table when we issue queries i.e. to stop read locks blocking our writes.

This works fine for normal select queries for our reporting but we seem to be having funny behaviour when accessing the table doing an insert select into another table, performing aggregations. It has been suggested that even through a view with 'locking row for access' modifier that the insert select upgrades the access lock to a read lock instead, which then blocks our write operations.

However an explain on the query shows the source table is locked for access. Can anyone confirm that the lock is upgraded to a read when issuing an insert select Vs a straight select?


Thanks in advance,

Craig



     
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