"MacGregor, Ian A." wrote: > > SQL> describe chanarch_nlc.archive_wave_i > Name Null? Type > ----------------------------------------- -------- -------------------------- > PV_ID NUMBER(38) > TIMESTAMP DATE > NANOSECS NUMBER(9) > STAT NUMBER(8) > SEVR NUMBER(8) > OSTAT NUMBER(16) > VALUE CHANARCH_NLC.INT_VALUES > > SQL> describe chanarch_nlc.arch_wave_i > Name Null? Type > ----------------------------------------- -------- -------------------------- > PV_ID NUMBER(38) > TIMESTAMP DATE > NANOSECS NUMBER(9) > STAT NUMBER(8) > SEVR NUMBER(8) > OSTAT NUMBER(16) > VALUE CHANARCH_NLC.INT_VALUES > > SQL> describe chanarch_nlc.int_values > chanarch_nlc.int_values VARRAY(16384) OF NUMBER(38) > > Select * from chanarch_nlc.arch_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > ORDER BY TIMESTAMP, NANOSECONDS > / > > Returns 1 row plus the associated varray data in one second > > Select * from chanarch_nlc.archive_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > ORDER BY TIMESTAMP, NANOSECONDS > > Returns 0 rows in about a second > > Select * from chanarch_nlc.arch_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > Union all > Select * from chanarch_nlc.archive_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > > Returns a single row with the varray data in a second > > However > > Select * from chanarch_nlc.arch_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > Union all > Select * from chanarch_nlc.archive_wave_i > Where pv_id = 433 and > Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' > Order by 2,3 > > Never returns. It waits forever on a sequential dbfile read event of one the files > used by the lob segment which contains the varray data for the value column of > chanarch_nlc.arch_wave_i. Nothing appears to be blocking the session. The query > plan is as one would expect. > > Similar queries against different tables with the same structure proceed without > incident. > > Ian MacGregor > Stanford Linear Accelerator Center > [EMAIL PROTECTED] > --
Ian, Independently from the fact that you have hit a bug, does select * from (Select * from chanarch_nlc.arch_wave_i Where pv_id = 433 and Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00' Union all Select * from chanarch_nlc.archive_wave_i Where pv_id = 433 and Timestamp between '18-SEP-2003:13:48:00' AND '18-SEP-2003:13:49:00') Order by 2,3 return ? (Perhaps /*+ NO_MERGE */ would help) -- Regards, Stephane Faroult Oriole Software -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Stephane Faroult INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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).