Re: Will Oracle support file compression under NT3.51?
Date: 1995/07/29
Message-ID: <3ved6p$gsn_at_news.pi.se>#1/1
But if you are aware of this side effect, and refrain from adding all those "extra" files to the disk where the table space was allocated, then it should work. I'm personally excited by this possibility; we have a large database (currently around 50 Gig) that grows by 5 to 10 Gig per year. This is sales data that is very static in nature, and is only used to run queries against. If it can be stored on compressed disks, then that would save us a bit in hardware costs. We are currently looking at gradualy moving over to an NT platform from Unix, and compressed disks would be a nice bonus.
/Anders
skanga_at_us.oracle.com (Shiraz Kanga) wrote:
:>In article <3uj267$8ea_at_helios.vanderbilt.edu> Randy Fought
<FOUGHTRL_at_CTRVAX.VANDERBILT.EDU> writes:
:>> The new release of the Windows NT3.51 OS has added file compression
:>>as an optional feature. Will Oracle operate correctly using a disk or
:>>disks that use an operating system level file compression?
:>>
:>> Does Oracle support file compression on any other platforms?
:>>
:>>Thanks Randy
:>
:>All current implementations of Oracle will NOT support compressed file
systems
:>on ANY operating system (but support is rumored to be coming). The
reason for
:>not supporting compression is because Oracle pre-creates data files
:when
:you
:>create tablespaces and NOT dynamically as data is inserted.
:>
:>Assume the following scenario:
:>
:>I have a 1 gig disk and I create a 500 M tablespace in a datafile on
this disk.
:>Initially this file is almost empty and therefore highly compressable.
:>Lets say it compresses to 10 megs. Now I happily keep adding other
:files
:onto
:>this disk until it's almost full. Assume only 1 meg of free space is
:now
:left.
:>
:>Now I go ahead and insert 450 megs into my Oracle table on that disk.
Oracle
:>thinks that's okay since it "knows" it has a 500 meg tablespace. The OS
gave
:>it to Oracle. But the disk has no room to expand and accomodate the
growing
:>compressed file. So BOOM it just blows up in your face. The results are
:>obviously going to be unpredictable but really bad.
:>
:>Hence Oracle cant support compressed filesystems.
:>
:>Could someone please add this to the FAQ (which never seems to get
posted)
:>
:>shiraz
:>
Received on Sat Jul 29 1995 - 00:00:00 CEST