After moving from 3.x to 4.x we see the time taken for pfmerge increases from 32 ms to 170 ms, wondering if this could be a side effect of this fix https://github.com/antirez/redis/issues/3819#issuecomment-362529354 and is by design?

thanks

Comment From: deepakverma

@antirez, what do you think about this issue? thanks

Comment From: antirez

Hello @deepakverma, yep, it's basically a tradeoff between space and time apparently :-( Before we used to promote to the sparse representation, that takes a lot more memory, but does not need to be parsed.