They
way Oracle uses bitmap indexes, they are very poor performance when doing large
writes, or data loads.
Oracle
actually shys away from their use for OLTP environments.
<FONT face=Arial color=#0000ff
size=2>
<FONT face=Arial color=#0000ff
size=2>Although bitmap indexes are very cool and can have very significant
performance gains, you must be very careful with them, they do not perform as
consistent as b-tree indexes and can sometimes pose performance problems due to
their increased complexity on writes.
"Walking on water and developing software from a
specification are easy if both are frozen."
Christopher R. Spence <FONT
face="Comic Sans MS" size=2>Oracle DBA <FONT face="Comic Sans MS"
size=2>Fuelspot
<FONT
face=Tahoma size=2>-----Original Message-----From: Koivu, Lisa
[mailto:lisa.koivu_at_efairfield.com] Sent: Monday, July 30, 2001
10:31 AMTo: Multiple recipients of list ORACLE-LSubject:
RE: bitmap indexes going wild
Hi Stephane,
your data loads will also be much
much quicker if you drop your bitmap indexes prior to the load. But then
you have to weigh the speed increase of your load against the time it will
take to rebuild the bitmaps. I believe the doco discusses why bitmaps
can slow down inserts.
Lisa Koivu Oracle Database
Administrator Fairfield Resorts, Inc.
954-935-4117
-----Original Message----- <FONT
face=Arial size=1>From: <FONT face=Arial
size=1>Deshpande, Kirti [SMTP:kirti.deshpande_at_verizon.com]
Sent: <FONT face=Arial
size=1>Monday, July 30, 2001 10:00 AM <FONT face=Arial
size=1>To: <FONT face=Arial
size=1>Multiple recipients of list ORACLE-L <FONT face=Arial
size=1>Subject: <FONT
face=Arial size=1>RE: bitmap indexes going wild
Stéphane, I
have seen such behaviour with bit mapped index since 7.3.4.x. The
index did not grow as much in 8.x
versions. But it was still unacceptable. We drop <FONT face=Arial
size=2>all bit mapped indexes prior to data loads and rebuild them
afterwards.
Regards,
- Kirti Deshpande <FONT face=Arial
size=2> Verizon Information Services <FONT face=Arial
size=2> <A target=_blank
href="http://www.superpages.com">http://www.superpages.com
> -----Original Message----- <FONT
face=Arial size=2>> From: paquette stephane
[SMTP:stephane_paquette_at_yahoo.com] >
Sent: Monday, July 30, 2001 8:30 AM >
To: Multiple recipients of list ORACLE-L <FONT
face=Arial size=2>> Subject: bitmap indexes
going wild > <FONT
face=Arial size=2>> Hi, >
> 3 bitmap indexes have gone pretty
big during data > insert. Once rebuild
they returned to their normal >
size. > They were previous loads
whitout any problem. >
> This is on Oracle 816 64bit/Solaris
5.7 > I checked on metalink but found
nothing. > Is there any known problems
with bitmap indexes on 816 >
64bit. > <FONT face=Arial
size=2>> I know I can disable the index and use <FONT
face=Arial size=2>> skip_unusable_indexes but since . <FONT
face=Arial size=2>> > =====
> Stéphane Paquette <FONT
face=Arial size=2>> DBA Oracle, consultant entrepôt de données
> Oracle DBA, datawarehouse consultant
> stephane_paquette_at_yahoo.com
> >
___________________________________________________________ <FONT
face=Arial size=2>> Do You Yahoo!? -- Vos albums photos en ligne,
> Yahoo! Photos : <A target=_blank
href="http://fr.photos.yahoo.com">http://fr.photos.yahoo.com
> -- >
Please see the official ORACLE-L FAQ: <A target=_blank
href="http://www.orafaq.com">http://www.orafaq.com <FONT
face=Arial size=2>> -- > Author:
=?iso-8859-1?q?paquette=20stephane?= <FONT face=Arial
size=2>> INET: stephane_paquette_at_yahoo.com <FONT
face=Arial size=2>> > Fat City
Network Services -- (858) 538-5051 FAX: (858)
538-5051 > San Diego,
California -- Public Internet
access / Mailing Lists >
> To REMOVE yourself from this mailing list,
send an E-Mail message > to:
ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
> the message BODY, include a line
containing: UNSUB ORACLE-L > (or the
name of mailing list you want to be removed from). You may
> also send the HELP command for other
information (like subscribing). --
Please see the official ORACLE-L FAQ: <A
target=_blank href="http://www.orafaq.com">http://www.orafaq.com
- Author:
Deshpande, Kirti INET:
kirti.deshpande_at_verizon.com
Fat City Network Services --
(858) 538-5051 FAX: (858) 538-5051 <FONT face=Arial
size=2>San Diego, California --
Public Internet access / Mailing Lists <FONT face=Arial
size=2>--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send
an E-Mail message to:
ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing:
UNSUB ORACLE-L (or the name of mailing
list you want to be removed from). You may <FONT face=Arial
size=2>also send the HELP command for other information (like
subscribing).
Received on Mon Jul 30 2001 - 11:38:12 CDT
