Re: Db2, Oracle, SQL Server

From: Mark A <nobody_at_nowhere.com>
Date: Sun, 6 Feb 2005 00:56:51 -0700
Message-ID: <g_udnUtZ26rIUJjfRVn-2Q@comcast.com>

"Mark D Powell" <Mark.Powell_at_eds.com> wrote in message
>
> The online logging is very different. In DB2 the onlne logs are not
> circular and are used for rolling back transactions.
>

In DB2 the default logging is circular when a database is created, but most people use log retain (non-circular) in production so that they can perform on-line backups and other on-line utilities. Sometimes circular logging is sufficient for data warehouses when a backup can be performed right after the data load. Log retain is used for rolling back transactions, roll-forward recovery, and replication.

> DB2 UDB keeps track of row level locks in memory.
>

DB2 keeps track of all locks (row or table) in memory. The size of the locklist memory is configurable. If the locklist memory becomes full, DB2 will start doing dynamic lock escalation from row locks to table locks, and log this event in a diagnostic log file.

> That is more than I want to remember until I have to pick up the
> project again.
>
> HTH -- Mark D Powell --
>
Received on Sun Feb 06 2005 - 01:56:51 CST