best new dating sites in the world Updating large tables

The interesting thing about this method is that it performs a context-switch between PL/SQL and SQL for every FETCH; this is less efficient.I include it here because it allows us to compare the cost of context-switches to the cost of updates.

The large update has to be broken down to small batches, like 10,000, at a time. It is also easy to restart in case of interruption.

WAITFOR DELAY can be included to slow down the batch processing.

Instead of updating the table in single shot, break it into groups as shown in the above example.

What I love about writing SQL Tuning articles is that I very rarely end up publishing the findings I set out to achieve. We have a table containing years worth of data, most of which is static; we are updating selected rows that were recently inserted and are still volatile. For the purposes of the test, we will assume that the target table of the update is arbitrarily large, and we want to avoid things like full-scans and index rebuilds.

Then a merge my temp table with t_wrong_ids but how exchange this temp table back?

begin -- 1 and 11 - hardcoded values, -- since your t_participants table has 11 000 000 rows for i in 1..11 loop merge t_contact c using (select * from t_participants where id between (i - 1) * 1000000 and i * 1000000) p on (= p.id) when matched then update ...; commit; end loop; end; I took size of a part 1000000 records, but you can choose another size. Query - 1: 0) BEGIN BEGIN TRANSACTION UPDATE Table Name SET Value = 'abc1' WHERE Parameter1 = 'abc' AND Parameter2 = 123 PRINT (@@ROWCOUNT) IF @@ROWCOUNT = 0 BEGIN COMMIT TRANSACTION BREAK END COMMIT TRANSACTION END SET ROWCOUNT 0 I've updated this from 1000 to 4000 and seems to be working fine so far.In one table I'm updating 5 million records (seems to be updating about 744,000 records every 10 mins). The where predicates would prevent this from working correctly.After that, the WHILE condition is dependent on the UPDATE statement’s row count.The WHERE clauses in callout B prevent the same row from being updated twice.I want to test on a level playing field and remove special factors that unfairly favour one method, so there are some rules: TEST (Update Source) - 100K rows TEST (Update target) - 10M rows Name Type Name Type ------------------------------ ------------ ------------------------------ ------------ PK NUMBER PK NUMBER FK NUMBER FK NUMBER FILL VARCHAR2(40) FILL VARCHAR2(40) Not many people code this way, but there are some Pro*C programmers out there who are used to Explicit Cursor Loops (OPEN, FETCH and CLOSE commands) and translate these techniques directly to PL/SQL.