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RE: identify CTAS from v$ tables

From: Joseph Amalraj <>
Date: Tue, 25 Apr 2006 19:19:35 -0700 (PDT)
Message-ID: <>

I tried the sql against v$sql and v$sqlarea and it did not return any rows.    

  Agreed, dictionary managed temporary tablespaces are a bad thing. Conversion to locally managed temporary tablespaces is to take place very soon.    

  During the period when ST enqueue blocking lock occurs, many times there have been "no rows" from v$sort_usage table.    



ramick <> wrote:

        v\:* {behavior:url(#default#VML);}  o\:* {behavior:url(#default#VML);}  w\:* {behavior:url(#default#VML);}  .shape {behavior:url(#default#VML);}                You should be able to get the sql text from v$sqlarea and v$sqltext.
  Something like:
  select hash_value, sql_text from v$sqlarea where   upper(sql_text) like 'CREATE TABLE%AS SELECT%';   if the SQL statement is less than 1000 characters.    

  If the statement is longer, use the hash_value above to get the pieces   from v$sqltext.    

  Are any of the CTAS doing sorting, merge or hash joins or grouping as part of their select? If so, they may be using a dictionary managed tablespace of type temporary or a permanent tablespace for their sort areas – this would require an ST enqueue for every allocation and de-allocation of extents. Permanent tablespaces are the worst for sort type operations as the sort segments are not reused – every process doing a disk sort will create and then drop it’s own sort segment.    



  From: [] On Behalf Of Joseph Amalraj Sent: Tuesday, April 25, 2006 4:00 PM
To: ramick
Cc:; Subject: RE: identify CTAS from v$ tables    

    In this case, dictionary managed tablespaces are being used, but the extents

    are properly sized. CTAS and drop table are the only sql that need space management. I have suggested, to move towards delete/insert and use of global temporary table where possible.      

    Most of the scripts use CTAS and run once in 30 minutes or 1 hour.      

    Any suggestions are welcome.      



ramick <> wrote:

      Apologies if I missed something, but are you sure the ST enqueue locks are the result of CTAS?      

    They could be anything that requires the allocation or deallocation of extents for any space management that is dictionary-managed.? Could be ?tablespaces of type temporary or permanent tablespaces.             


    From: [] On Behalf Of Joseph Amalraj Sent: Tuesday, April 25, 2006 2:15 PM
To: Stephane Faroult
Cc:; Subject: Re: identify CTAS from v$ tables      

      In this database, there are 'ST' enqueue locks and i have to identify the SQL statements issued by blocking and blocked sessions. I cannot use DDL triggers.        



Stephane Faroult <> wrote:


Would a DDL trigger be an acceptable solution to you? I haven't tried it recently, but I *think* that you can catch the statement text in the trigger. I am not fully certain about that, because since DDL statements are nothing else (ultimately) than DML statements applied to dictionary tables some are broken into their constituent DML components so fast that they let no track in the SGA. Otherwise perhaps that V$object_dependency could help too ...

HTH Sté°¨ane Faroult

Joseph Amalraj wrote:

> After going thru' the v$fixed_view_definition for v$sql, v$open_cursor
> and
> v$sqltext, I could only get the name of the table being created by the
> following query.
> sys_at_clfypurg > select kglnaobj from x$kgllk where
> kgllkmod = 3;
> ------------------------------------------------------------
> if "alter session set sql_trace = true" is run before executing CTAS
> the trace
> does generate the CTAS sql statement.
> Can the sql be found from any x$ table ??
> Thanks
> Joseph
> */Michael McMullen /* wrote:
> Here's what TOAD uses but as I recall you can't get the underlying
> DDL statement for CTAS. Maybe changed in 10g.
> SELECT sql_text
> FROM v$sqltext_with_newlines
> WHERE hash_value = TO_NUMBER (:HASH)
> ORDER BY piece

Received on Tue Apr 25 2006 - 21:19:35 CDT

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