Oracle9i allows us to use Record structures during bulk operations so long as we don't reference individual columns of the collection. This restriction means that updates and deletes which have to reference inividual columns of the collection in the where clause are still restricted to the collection-per-column approach used in Oracle8i.
Bulk binds can improve the performance when loading collections from a queries. To test this create the following table. The following code compares the time taken to populate a collection manually and using a bulk bind. The select list must match the collections record definition exactly for this to be successful. Remember that collections are held in memory, so doing a bulk collect from a large query could cause a considerable performance problem.
In actual fact you would rarely do a straight bulk collect in this manner. Instead you would limit the rows returned using the LIMIT clause and move through the data processing smaller chunks.
This gives you the benefits of bulk binds, without hogging all the server memory. The following code shows how to chunk through the data in a large table. So we can see that with a LIMIT we were able to break the data into chunks of 10, rows, reducing the memory footprint of our application, while still taking advantage of bulk binds.
The array size you pick will depend on the width of the rows you are returning and the amount of memory you are happy to use. In my opinion no. Per th question, if you only want to continue updating even if record fails with error logging then i think you should go with the DML error logging clause of Oracle. Hope this helps. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Bulk update with commit in oracle Ask Question. Asked 4 years, 10 months ago. Active 1 year, 7 months ago.
Viewed 22k times. Improve this question. OldProgrammer Thej Thej 2 2 gold badges 5 5 silver badges 17 17 bronze badges. Why do you think you need to do a commit every 5K? Also see here asktom. We can do that using the following logic. The following example shows how to accomplish this. It would make argument passing trivial and avoid that substr trick alltogether. Use numbers between say and to see what works best for you. Don't go overboard!!
The advantage to that is various tools use that table to show progress -- as well, it will estimate the time to completion for you when possible. We might ask for rows -- our last fetch will get say 55 rows -- notfound will be set but we need to process those last 55 FIRST before we exit! Rating 46 ratings Is this answer out of date? You can also catch regular content via Connor's blog and Chris's blog.
Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. And of course, keep up to date with AskTOM via the official twitter account. Question and Answer. You Asked Sorry for the confusion.
For maintainability, and since I'm a lazy typist, I'd make a couple of changes to the code pro-forma. January 04, - pm UTC. Oh, that you could Tom, I plan on sharing this with all of our developers. Hi Tom, Thanks for this explanation. I've tried several times to manage this but couldn't.
January 08, - am UTC. Just a doubt Neeti, January 08, - pm UTC. My question is related to the same in this thread where user wants to collect in bulk and process the data. Why are using an extra step to process the array of records and then updating the data in next step.
January 08, - pm UTC. N update Never knew one could do this using Oracle. Just great! Hi Tom I have a procedure which takes 10 hours to process 1 million rows, I am not sure if it can be optimized with forall array processing. Can this kind of process use array processing? Or conventional cursor is the only bet? August 23, - pm UTC. Lets see the blah blah blahs try to put it in a question, not in a review.
I'll betcha we can avoid a ton of the row by row stuff. Why this gives error? Shaji, May 13, - am UTC. Why this gave such error and in your case not? May 13, - am UTC. I had a record of array's totally different data structures. Tom, If you could, can you highlight the differences between an "record of arrays" and "array of records" with some simple examples.
And when one might use what? May 13, - pm UTC. One would use a record of arrays in 8i to facilitate bulk collects whilst using a record. Hi Tom, Is it possible to bulk append to a collection. Say I have a collection x that already has 5 elements populated. Now I want to add 10 elements to it. Is there a way to avoid, in the case of nested table, doing loop x. May 14, - am UTC. No, not really.
You can optimize the extend by extending all N at once but then you would be doing singleton assignments to move the second collection into the first. Hi Tom, I just overlooked your above emprec definition. Thanks a lot for the clarification. Shaji, May 14, - am UTC. Hi Tom, I just overlooked the emprec definition.
Thanx for the clarification. And does this resolve the lock issue? We have these update statements in our batch jobs that get kicked off every night at same time. The values for the columns come from different sources.
Your help would be much appreciated. May 15, - am UTC. ROWS are locked, not columns. Thanks Tom. I thought so, but just want to confirm.
It works! Bulk updates lakshmi, May 15, - am UTC. Dear Tom, One of my daily night process takes around 12 hours to completes which processes around 6 Lakhs of rows. The logic built was that the number of rows to be processed are inserted into a table which is first truncated. The logic built by the application tea was declare define a cursor begin for cursor loop processing I wanted to use bulk collect feature using records as shown by you in the top.
But when compared to single processing the tieme taken is same in both the cases. Based on the logic developed by our developer, I have created a package with both the options Bulk Fetch and Single Fetch. The check was made for rows.
0コメント