After table partitioning(Hash by partition 4) observed increased in total memory consumption on memory on disk. Earlier we did the partition (Hash by partition 12) observed decreased in total memory consumption on memory on disk.
Both tables are SLT tables and memory dumps are taken before resuming slt replication.
What is the reason of either increase or decrease in memory can anyone explain?
Without the table and column details (i.e. from system view
M_CS_ALL_COLUMNS) we can only speculate about the reasons in this case.My guess is that the compression of the individual columns now (with 4 partitions) is less efficient than before (12 partitions).
Since HANA does perform compression optimisation - that is, it tries to find the best compression algorithm for every column in a table, given all other columns - this might have changed after the re-partitioning.
Another option is that this compression optimisation actually hasn't been done yet. In that case, you can run
UPDATE <table name> WITH PARAMETERS ('OPTIMIZE_COMPRESSION' = 'FORCE)to manually trigger it.