Re: this is in plain text (row level locks)
From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Jenny -" <nat_lazy@hotmail.com>
Subject: Re: [HACKERS] this is in plain text (row level locks) Date: Sat,
02 Aug 2003 23:28:30 -0400if row-level locks are not recorded in proclock or any other shared
memory
datastructuers, then why does lockmode (array or ints) of proclock
indicate
that an AccessShareLock is acquired when a row is locked by
application.?
That's a table lock --- it's independent of row locks. It's there
mostly to ensure someone doesn't delete the whole table out from under
you.regards, tom lane
so even though the application locks a row in a table, table-level locks are
automatically taken by postgesql ? why is that?
thanks
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"Jenny -" <nat_lazy@hotmail.com> writes:
so even though the application locks a row in a table, table-level locks are
automatically taken by postgesql ? why is that?
So that the table doesn't disappear while you're trying to scan it. (Or
afterwards --- a row-level lock wouldn't be noticed by DROP TABLE.)
Note that AccessShareLock is a pretty weak kind of lock, and holding it
does not prevent most other operations.
regards, tom lane