Comments on: Increasing the speed of APEX Collections

By: John Scott

John Scott — Mon, 04 Apr 2011 06:54:08 +0000

Hi Damir,

I’m not entirely sure I understand your question? The two examples call different routines -

CREATE_COLLECTION_FROM_QUERY
CREATE_COLLECTION_FROM_QUERY_B

John.

By: Damir

Damir — Sun, 03 Apr 2011 15:23:58 +0000

Hi!

I do not understand what is the difference in mentioned two examples!??

AFAIK, if parameter is not required then default value is assigned, and in thi scase it is “N” as in your first example…

Any comment?
THX
Damir

By: Denise

Denise — Wed, 16 Feb 2011 14:58:02 +0000

Hi John,
although you posted this a long time ago I just came across this bit of code as faced a problem with my collections. Usually I don’t have any problems with collections but now it hit me. Anyway, I would like to tell you my problem and then maybe you will have a tip or something:
I am having a manually created tabular form with a checkbox as first column. When rows are ticked and button is pressed the page is submitted. A process will run:
1. if collection exists, delete it
2. create collection
3. loop through ticked rows APEX_APPLICATION.G_F01.COUNT
4. add members to collection APEX_COLLECTION.ADD_MEMBER(
p_collection_name => v_coll_name,
p_c001 => apex_application.g_f02(APEX_APPLICATION.G_F01(i)),–id
a few more columns are coming up
5.when I run the page in debug mode the process will run 90!! seconds.
For one week long it ran fine. I don’t know what happened all of a sudden to run so long.
Do you have an idea?
Any help is highly appreciated.
Thanks in advance
Denise

By: Jeff Kemp

Jeff Kemp — Mon, 15 Mar 2010 07:06:40 +0000

Great tip, thanks!\n\n”18 seconds is a long time for an user to wait for something to happen in a web application”\n\nI would have said, “18 seconds is a long time for a user to wait for something to happen in a web application, unless they specifically asked for all 55,000 records to be retrieved and shown on the page.”

By: John Scott

John Scott — Thu, 25 Feb 2010 09:31:21 +0000

Peter,

Thank you, yes I have a few more (draft) posts relating to collections that I should be publishing soon (when I get a chance to finish them).

John.

By: John Scott

John Scott — Thu, 25 Feb 2010 09:30:48 +0000

Joel,

Thank you and thanks for the heads up on the 4.0 improvements, I can see those being *extremely* useful!

John.

By: Olivier Dupont

Olivier Dupont — Thu, 25 Feb 2010 08:43:31 +0000

Hey John,

I use collections a lot but never the CREATE_COLLECTION_FROM_QUERY_B option.

Thanks for the tip.

By: Peter Raganitsch

Peter Raganitsch — Thu, 25 Feb 2010 06:01:09 +0000

Hi John,

thanks for this hint, i’ll try this.

Do you have any further tips or best practices when dealing with collections? When to use and when not?

thanks,

Peter

By: StewS

StewS — Wed, 24 Feb 2010 21:40:45 +0000

John,

Thanks for the good tip and the statistics.

Thanks to Joel for the hint about the new and improved version upcoming.

By: Joel R. Kallman

Joel R. Kallman — Wed, 24 Feb 2010 17:51:56 +0000

Nice post, John. It’s one I’ve always wanted to write.

What you’ll see in APEX 4.0 (and in the upcoming refresh of the Early Adopter’s instance of APEX 4.0) are three new parameters to create_collection_from_query_b, namely p_names and p_values, so you can pass in the bind variable names and values for your query, and p_max_row_count – so you can easily limit the number of rows populated in the collection, instead of having to write our own outer SELECT.

Also, the part about the limitation of 2,000 bytes for VARCHAR2 no longer applies if you’re running DB 11gR2 (where the DBMS_SQL.VARCHAR2_TABLE type was finally resized to a table of VARCHAR2(4000)).

Joel

By: Mark Lancaster

Mark Lancaster — Wed, 24 Feb 2010 10:52:47 +0000

Hi John

That’s a really good tip to remember.

I can’t say I’ve ever used a collection to load 55,000 records, but agree entirely with you that collections are a great feature.

Every time I use them I keep saying I should use collections more often.