Re: Exchange Partitions

In theory (viz in the manuals) the data set remains read-consistent for all current queries.
i.e. a query that started before the exchange partition would see the data in the previous
incarnation of the partition.

In practice I have had a couple of catastrophic bugs appear such as:

	queries aborting
	queries stopping instantly and returning the wrong results
	

BTW - when you exchange a partition, the entire table definition is invalidated,
so all relevant dictionary cache entries (partition, indexes, index partitions,
constraints etc.) are flushed and reloaded - this can be quite expensive if you
have a large number of partitions.

Jeff Anderson <janderson_at_iname.com> wrote in article <6qfcl2$m1o$1_at_ash.prod.itd.earthlink.net>...
> We are considering using the EXCHANGE PARTITION command in Oracle8
to do
> mass updates to specific table partitions. The database needs to be
up 24x7.
> What effect would exchanging the partition have on active queries
across the
> partition that is being exchanged? Does Oracle allow you to
exchange the
> partition when the partitioned table is online and in use? Would
the users
> query just return unstable results or would it error out? If anyone
has had
> experience with this issue I would appreciate your input.
Received on Sun Aug 09 1998 - 16:32:02 CDT