"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]

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