RE: SQL*Net message from client

From: Subbiah, Stalin <SSubbiah_at_netopia.com>
Date: Thu, 3 Jun 2004 18:16:16 -0700
Message-ID: <F1F84A2E5F9EBD46A9BDB905EB5B10393A48@mxca1.netopia.com>

Thanks Stephane.

This is exactly what I wanted to do rather doing all individual insert/updated statements from a loop, just have one insert select and update to sync the data and generates less redo/undo too.

---

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Stephane Faroult
Sent: Thursday, June 03, 2004 2:19 AM
To: oracle-l_at_freelists.org
Subject: Re: SQL*Net message from client

Stalin,

    I recognize a familiar pattern ... Could it be the dreaded usual

    select count(*) into boink
    from yaddayadda
    where ...
    if (boink = 0)
    then
      insert into yaddayadda ..
   else

      update yaddayadda ...
  end if;

The bad news is that you won't get much improvement (if any) without touching the code.
The good news is that you can probably improve performance by a magical factor with not much rewriting.
The myopic advice would be to use UPDATE/test ROWCOUNT/INSERT if 0. However, in your special case, that would mean running the GROUP BY one the HITS_FACT table twice for INSERTs (because you would do it for the failed UPDATE first). It can be viable if INSERTs are few relative to UPDATEs - since SQL*Net latency is your problem, it would reduce database calls by a factor of almost two.
However, I feel more concerned by your :p1 and :p2 parameter. I fear that you are running all this in a loop.
If I were you, I would get rid of the loop and execute first

UPDATE summary_hits_fact shf
SET (hit_count) =
(SELECT count(*)

FROM hits_fact hf
WHERE shf.page_hit_key = hf.page_hit_key AND shf.hit_date_key = hf.hit_date_key);

(assuming that there is no (page_hit_key, hit_date_key) pair in the summary
table which cannot be found in the main table) - not stellar, but definitely not worse than what you currently have -

then

INSERT into summary_hits_fact
SELECT hf.page_hit_key, hf.hit_date_key, count(*) FROM hits_fact hf
WHERE (hf.page_hit_key, hf.hit_date_key)

          not in (select /*+ MERGE_AJ */
                                page_hit_key, hit_date_key
                     from summary_hits_fact)

GROUP BY hf.page_hit_key, hf.hit_date_key

Only two statements, and no more network problem ...

A pity you are on 8.1.7, on 9.X you could have used MERGE and a single statement.

HTH, Stephane Faroult

On Wed, 2 Jun 2004 19:15 , 'Subbiah, Stalin' <SSubbiah_at_netopia.com> sent:

	SELECT count (*) from summary_hits_fact shf where
	shf.page_hit_key = :p1 AND shf.hit_date_key = :p2
	
	INSERT INTO summary_hits_fact
	(page_hit_key, hit_date_key, hit_count)
	SELECT hf.page_hit_key, hf.hit_date_key, count(*)
	FROM hits_fact hf
	WHERE hf.page_hit_key = :p1
	AND hf.hit_date_key = :p2
	GROUP BY hf.page_hit_key, hf.hit_date_key
	
	UPDATE summary_hits_fact shf
	SET (hit_count) = 
	(SELECT count(*)
	FROM hits_fact hf
	WHERE shf.page_hit_key = hf.page_hit_key
	AND shf.hit_date_key = hf.hit_date_key)
	WHERE shf.page_hit_key = :p1
	AND shf.hit_date_key = :p2
	


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Received on Thu Jun 03 2004 - 20:13:16 CDT