Re: is an explicit lock necessary?

On Thu, May 04, 2006 at 11:10:56AM -0700, Ash Grove wrote:
> Hi,
>
> Does beginning a transaction put locks on the tables
> queried within the transaction?

You mean like a table lock? No. A transaction does entail some
locks: for instance, an access exclusive lock will block behind your
share lock while you're looking at the table (because the exclusive
lock wants to be exclusive, of course). See the concurrency control
section of the manual.

> In the example below, is #2 necessary? My thought was

No. currval() is local to your _session_ (not even your
transaction). The docs explain how this works.

A

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