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Oracle SQL database In-Memory - compare compressions sizes

I'm playing with in-memory storage in oracle sql. I would like to compare the results of compression, I meant the amount of used space. For example, I'm running these queries:

ALTER TABLE RENTING INMEMORY MEMCOMPRESS FOR QUERY LOW(RETURN_DATE);

vs

ALTER TABLE RENTING INMEMORY MEMCOMPRESS FOR CAPACITY HIGH(RETURN_DATE);

Is there any easy way to check the size used by these compressions in SQL developer?

I found this article https://blogs.oracle.com/in-memory/database-in-memory-compression, there is a table containing 'space used' for each type of compression. This exactly what I am trying to do on my own. Thanks for any advices.

Solution

  • Querying v$im_segments after population will show you how many bytes from the table were loaded and how much of the in-memory store was utilised.