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Just click on the left to register today! If you are brand new to Database Technology, then we also have got you covered. Question and Answer Thanks for the question, Pablo. This process will delete 1,5 millons. This process took more than 4 hours to finish and generated a huge amounts of archives. So there is an image of the rows in rollback which are currently not present in the table.

Hence the phrase 'before image'. Now all the rollback blocks are written to the redo log files too. So you have the oracle updating chunks big table blocks with the table without the deleted rows, of course and the rollback blocks with the old image both producing redo, which accounts for additional archive logs.

I cant comment on the ratio of deleted records to ratio of redo produced, though. If you do an insert, only the rowid is stored in the rollback segs, which generates less redo. Depending on the number of rows in your tables, it may be better for you to insert the records you dont want to delete into a temp table, truncate the main table and move the records back to the main.

This would probably generate oracle updating chunks big table redo than delete, but that depends on number of rows. How deallocate extents from the table?

Thanks in Advance and sorry for my english Pablo R. Well, 2 is the slowest way and generates the most amount of redo by far. So, in this case the insert might do as much as the delete. Each partition will use its own rollback segment, each will run in parallel. 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 oracle updating chunks big table, keep up to date with AskTOM via the official twitter account.

Oracle updating chunks big table Deleting many rows from a big table. Question and Answer. Latest Followup. You Asked Tom: We have a 6 millons rows table and we need to clean it. Write a Review.

Tom: Regarding with the 3 methods described above, 1, 2 don't deallocate space extents however the last approach allows redefine the table storage reset HWMso we recover tablespace space.

TomWe faced a similar situationwhere in we had to delete millions of rows based on ceratin date. Since ours is a continuouslu updated table we could not follow approach 1i.

This way we avoid rollback segement contention and at the same time we also avoid frequent commit instead of commit for every row This solution really works fast for us. As a variation on the partitioning and the CTAS options, in the past I have defined the table to have a single partition, used CTAS to create a table of the same structure with the data to be kept, and performed a partition exchange to swap the original and the new data sets.

The advantage for oracle updating chunks big table was that I could use the "excluding indexes" option, and perform index rebuilds instead of coding the index creation scripts. Less maintenance if indexes are added, dropped or modified. Oh, and it also handily kept the old data set handy in case of a screwup. Hi Tom: I have several tables about 1 million rows that I want to delete some of the records 20, to 50, rows for sure. I want a quick DELETE and there is no requirement to generate rollback data because the data are definitely not needed.

What do you think is the best way to delete them? Any thoughts. Sorry, forgot to mention. Some of the tables contain Indexes. Tom, Why do you think that the following approach is not the fastest one? Create a new table with only data that are NOT to be deleted and then drop the original table. Thanks and regards Praveen.

Tom You are extremely oracle updating chunks big table You mentioned somewhere above that if we delete data from muliple partitions, the deletions will happen in parallel per partition. Is this automatic? Thanks so much. I don't understand why Oracle doesn't provide parallel dml update and delete on non-partitioned big table.

Actually, I wrote such a utility using shell and sqlplus and it works fine. The commit limitation on pdml on partitioned table also applies. Currently doing simple timed deletes filtered by date This article presents lots of options. Still not sure which way to go Unable to extent Index while deleting records from a table.

Dear Tom, I have a table partition with around 21 Million Records and based on oracle updating chunks big table condition, I am deleting 1 Million records. While deleting, I am getting ora error. What could be the reason? Thanks and Regards Vivek. Dear Tom, Your above explanation is not clear and convincing. If it does that other oracle updating chunks big table, then why? When I delete a record, it has just got to delete the oracle updating chunks big table from the Index Block then why is it extending the index?

It did not changed. Could it be because of that? Regards Vivek. How to know much have been deleted. I have to delete them during the weekend within 40 hr. The delete has been going on for about 30 hrs.

If I know the deletion takes too long, I will use echte hausgemachte fotos von nackten madchen approach, such as deleting 1 Millions or less for each batch.

By the way, I can not use "create table" method since the table is always in use. My question: Is there any way to know how long the deletion will take or how much have been deleted? Oracle Thanks so much for your help. How much deletion is done.

Hi Tom, The combination of three columns is supposed to be unique, but we never put unique constraint on it. We are in the process to clean up and redesign this table. Thanks so much for your query and it is running now. I still would like to know much have been deleted before it is done.

Since I have setup large undo retention time for this operation, I can not let this operation going on for too long, otherwise my undo tablespace will be full. Are there any dictionary views to monitor this deletion? How to monitor the deletion. Hi Tom, Though my deletion has been running for about 24 hr. Possible new Oracle feature?? What about the data you are NOT deleting, is that data needed???? If not, just truncate and be done nackt indischen desi tantchen bh it.

They don't care if the data is lost or corrupted or whatever, it is garbage and is not needed anymore. So the quicker they can delete the rows, the better. Tom, I think you may have answered this question somewhere. I need a clarification regarding delete statement running in parallel say forcing by hint.

Cases: 1. Similar questions for the update statement too. I need to know how parallelism work on all the 4 cases. Will there be any deadlock issues when running anyone of them in parallel? In oracle updating chunks big table 3, will parallel process executes multiple partitions at a time? Is "alter session enable parallel dml" required for any of the above cases? Thanks a lot. Thanks for the explanation. We have oracle version 9. Parallel DML should not be a problem in this case.

I need some more clarification of you statement


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