Re: The mystery of concurrent access

P.V.,

> When 2 processes/people are simultaneously working on a table
> 
> * does Postgres automatically enforce some sort of locking?
> * do the changes made by process A become visible to process B
> immediately 
> (of course, the result of a SELECT wouldn't change dynamically, but
> suppose 
> process B did another SELECT, would it access process A's records?)

Please read:

http://www.postgresql.org/idocs/index.php?mvcc.html

-Josh

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