RE: can/do indexes chain?
Even for inserts, index key values cannot span multiple blocks. An attempt to create an index where a single key value won't fit in a single block will result in an ORA-1450 "maximum key length exceeded". -- Anita --- "Hillman, Alex" <[EMAIL PROTECTED]> wrote: > Update in the index is done as delete and insert, so > there is no chaining. > > Alex Hillman > > -Original Message- > Sent: Thursday, July 05, 2001 5:46 PM > To: Multiple recipients of list ORACLE-L > > > I've been asked to create an index which combines > two fields, date & > location. > For reasons I don't really want to explain, we > need/desire this index to > be in the order of date, location. The minor gotcha > is that while location > will be populated at the time the record is created, > the date field is not > updated until a later point in time. This date is a > document print date. > So this date field will be going from a NULL value > to a non-null value. > I recognize that this can result in record chaining > in the data table. > In thinking about this, I realized this could have a > similar affect > within the index. However, I've never read anything > about index chaining. > > Do/can indexes chain? > Should I be concerned about this? > > > -- > Charlie Mengler Maintenance > Warehouse > [EMAIL PROTECTED] 10641 Scripps > Summit Ct. > 858-831-2229 .NET? Not yet!San Diego, CA > 92131 > -- > Please see the official ORACLE-L FAQ: > http://www.orafaq.com > -- > Author: Charlie Mengler > 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: Hillman, Alex > 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!? Get personalized email addresses from Yahoo! Mail http://personal.mail.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: A. Bardeen 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: can/do indexes chain?
Update in the index is done as delete and insert, so there is no chaining. Alex Hillman -Original Message- Sent: Thursday, July 05, 2001 5:46 PM To: Multiple recipients of list ORACLE-L I've been asked to create an index which combines two fields, date & location. For reasons I don't really want to explain, we need/desire this index to be in the order of date, location. The minor gotcha is that while location will be populated at the time the record is created, the date field is not updated until a later point in time. This date is a document print date. So this date field will be going from a NULL value to a non-null value. I recognize that this can result in record chaining in the data table. In thinking about this, I realized this could have a similar affect within the index. However, I've never read anything about index chaining. Do/can indexes chain? Should I be concerned about this? -- Charlie Mengler Maintenance Warehouse [EMAIL PROTECTED] 10641 Scripps Summit Ct. 858-831-2229 .NET? Not yet!San Diego, CA 92131 -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Charlie Mengler 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: Hillman, Alex 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: can/do indexes chain?
Charlie Mengler wrote: > > I've been asked to create an index which combines two fields, date & location. > For reasons I don't really want to explain, we need/desire this index to > be in the order of date, location. The minor gotcha is that while location > will be populated at the time the record is created, the date field is not > updated until a later point in time. This date is a document print date. > So this date field will be going from a NULL value to a non-null value. > I recognize that this can result in record chaining in the data table. > In thinking about this, I realized this could have a similar affect > within the index. However, I've never read anything about index chaining. > > Do/can indexes chain? > Should I be concerned about this? > > -- > Charlie Mengler Maintenance Warehouse > [EMAIL PROTECTED] 10641 Scripps Summit Ct. > 858-831-2229 .NET? Not yet!San Diego, CA 92131 Charlie, For what I remember of B*Trees (not even the B*+%$# used by Oracle), indexes do not chain, they split. Since the date is the first column, updating it will totally reorder the index each time. I am currently wondering what would be the worst, between this and partitioning by range of date and allowing rows to migrate. Same kind of thing. It is likely to be very ugly. If this is possible, I'd rather drop the index, do the update, and recreate the index. -- Regards, Stephane Faroult Oriole Corporation Voice: +44 (0) 7050-696-269 Fax:+44 (0) 7050-696-449 Performance Tools & Free Scripts -- http://www.oriole.com, designed by Oracle DBAs for Oracle DBAs -- -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Stephane Faroult 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).
