This message was deleted.
# troubleshootings
Slackbot
01/31/2023, 1:30 AMThis message was deleted.
c
Clint Wylie
01/31/2023, 1:35 AMwe switched to using roaring bitmaps for indexes by default in druid 0.18, it could be related to that if you have lots of super high cardinality columns
👍 1
Clint Wylie
01/31/2023, 1:36 AMClint Wylie
01/31/2023, 1:36 AMperformance is like a ton better with roaring though so the size is probably worth it unless you were never filtering by those columns
d
Didip Kerabat
01/31/2023, 1:38 AMyeah, roaring bitmap is definitely preferable. I don’t want to switch it off
c
Clint Wylie
01/31/2023, 1:39 AMactually if you’re never filtering on the column, the better option is to not write indexes for it, there is a flag on dimension schema to control
d
Didip Kerabat
01/31/2023, 1:40 AMyes, that is what we usually do
c
Clint Wylie
01/31/2023, 1:40 AM👍
d
Didip Kerabat
02/01/2023, 12:46 AMAnother related question, could imperfect rollup impacted the smoosh file?
c
Clint Wylie
02/01/2023, 4:02 AMyeah totally
Clint Wylie
02/01/2023, 4:02 AMalso column order can play a pretty big role
Clint Wylie
02/01/2023, 4:06 AMif you’re on the latest version of druid and feeling adventurous and looking to make segments smaller, i did a thing that seems pretty cool in tests so far that added an option at ingest time to make the strings stored in segments smaller, particularly if they have lots of shared prefixes, such as urls
Clint Wylie
02/01/2023, 4:06 AMClint Wylie
02/01/2023, 4:07 AMits not really backwards compatible, so only make segments like that if you don’t need to read them on any older versions of druid
Clint Wylie
02/01/2023, 4:08 AMalso definitely experiment with your workload to ensure there are no performance regressions that i’ve missed before using in production
d
Didip Kerabat
02/03/2023, 6:14 AMah… thank you for your information!