Re: Bitmap vs btree - how to tell? how to test?
low cardinality -- good candidate for bitmap. little or no updates to the column being indexed -- good candidate for bitmap low cardinality is relative -- 10,000 distinct values in a 300m row table is low, 100 distinct values in a 10K row table might be high but the main criteria I have found is whether or not the column is updated because when you update the values in a bitmap index, it's not just the one row in the index that is updated but the entire segment of the bitmap. And THAT can lock the index on you. Rachel --- Jack Silvey [EMAIL PROTECTED] wrote: Listers, We are creating indexes on a 300m row fact table today. I am researching bitmap versus btree (again) to see where the latest info points. Anyone care to comment on the way to determine whether an index should be a btree or a bitmap? Anyone even know a good way to test this? thx, /jack __ Do You Yahoo!? LAUNCH - Your Yahoo! Music Experience http://launch.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jack Silvey INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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). __ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Rachel Carmichael INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
Re: Bitmap vs btree - how to tell? how to test?
On 2002.05.25 17:38 Rachel Carmichael wrote: low cardinality -- good candidate for bitmap. little or no updates to the column being indexed -- good candidate for bitmap low cardinality is relative -- 10,000 distinct values in a 300m row table is low, 100 distinct values in a 10K row table might be high but the main criteria I have found is whether or not the column is updated because when you update the values in a bitmap index, it's not just the one row in the index that is updated but the entire segment of the bitmap. And THAT can lock the index on you. Rachel Well, it doesn't exactly lock the whole index, it locks only the rows that have the same bitmap value as the row that is being updated. For a low cardinality column, that may mean locking down a significant portion of the index (and the underlying table, of course). That makes bitmap indexes (and indices) completely unsuitable for the OLTP environment. -- Mladen Gogala -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Mladen Gogala INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
Re: Bitmap vs btree - how to tell? how to test?
I am on leave from May 29 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
Re: Bitmap vs btree - how to tell? how to test?
I am on leave from May 29 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
Re: Bitmap vs btree - how to tell? how to test?
LOL Autoreply. I hope that they can block this guy PDQ or we'll be swamped. Anand Prakash AnandPrakashTo: Multiple recipients of list ORACLE-L @firsthealth.[EMAIL PROTECTED] com cc: Sent by: rootSubject: Re: Bitmap vs btree - how to tell? how to test? 05/24/2002 02:00 PM Please respond to ORACLE-L I am on leave from May 29 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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: http://www.orafaq.com -- Author: Thomas Day INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
RE: Bitmap vs btree - how to tell? how to test?
Either that, or we can contact Jaspreet. Tom Mercadante Oracle Certified Professional -Original Message- Sent: Friday, May 24, 2002 2:29 PM To: Multiple recipients of list ORACLE-L LOL Autoreply. I hope that they can block this guy PDQ or we'll be swamped. Anand Prakash AnandPrakashTo: Multiple recipients of list ORACLE-L @firsthealth.[EMAIL PROTECTED] com cc: Sent by: rootSubject: Re: Bitmap vs btree - how to tell? how to test? 05/24/2002 02:00 PM Please respond to ORACLE-L I am on leave from May 29 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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: http://www.orafaq.com -- Author: Thomas Day INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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: http://www.orafaq.com -- Author: Mercadante, Thomas F INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
RE: Bitmap vs btree - how to tell? how to test?
I am on leave from May 27 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
Re: Bitmap vs btree - how to tell? how to test?
He's just been put in digest mode. It's good to be king. ;) Jared On Friday 24 May 2002 11:28, Thomas Day wrote: LOL Autoreply. I hope that they can block this guy PDQ or we'll be swamped. Anand Prakash AnandPrakashTo: Multiple recipients of list ORACLE-L @firsthealth.[EMAIL PROTECTED] com cc: Sent by: rootSubject: Re: Bitmap vs btree - how to tell? how to test? 05/24/2002 02:00 PM Please respond to ORACLE-L I am on leave from May 29 to July 15. Please contact Jaspreet Jajj at x4338 for any query. Thanks. Anand Prakash -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Anand Prakash INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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: http://www.orafaq.com -- Author: Jared Still INET: [EMAIL PROTECTED] 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: [EMAIL PROTECTED] (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).
