May 2018
Intermediate to advanced
576 pages
30h 25m
English
The collect_deltas() function simply appends data to the same tables. This should not cause performance problems, as the large log tables are without indexes. Thus, insertions in them are fast, but if you are low on disk space and have many tables, you may want to introduce a rotation scheme for these tables that throws away older data.
In case you experience performance issues with the proposed approach, you might want to either purge the old data from the *_delta_log tables (and keep a window of the last four weeks) or use horizontal partitioning.
In the first approach, you can set a weekly cron job that deletes all records that are older than four weeks from the tables. For this purpose, we have created the rotate_deltas() ...