Hi! How do you verify that your session is still waiting on sequential read? >From v$session_event? Is the status column saying WAITING there? (if it says WAITED%, then your CPU is doing something else already, and this record in session wait just shows the last wait).
Tanel. ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Saturday, September 20, 2003 12:54 AM > 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] > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: MacGregor, Ian A. > 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). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Tanel Poder 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).
