Problem

In PR #14897 streamMoveIdmpKeys() was implemented such that it takes in int slot as input parameter and iterates over server.db[0].stream_idmp_keys and moves the keys which belong to slot into stream_idmp_keys.

Therefore asmTriggerBackgroundTrim() was calling streamMoveIdmpKeys() for each slot in trim ranges.

Time Complexity

Lets say number of slots be S (it could be 16,384 in worst case)
and let K be number of keys in server.db[0].stream_idmp_keys
then the total time complexity would be O(S x K)

Suggested Fix

we have changed the implementation of streamMoveIdmpKeys() such that it now takes in slotRangeArray *slots as an input parameter and iterates over server.db[0].stream_idmp_keys once, catching all the keys which fall in the slots range and moving them to stream_idmp_keys

Therefore asmTriggerBackgroundTrim() would now call streamMoveIdmpKeys() just once.

Time Complexity

say R is number of ranges in slots and let K be number of keys in server.db[0].stream_idmp_keys
then the total time complexity would be O(R x K)

since O(R x K) is better than O(S x K) because number of slots would almost always be greater than number of ranges in slotRangeArray *slots
(for a single merged range like 0–16383, R = 1 but S = 16 384).