right! silly me (regarding "can't have null for clustering column") :-)
OK code is modified, we stopped using NULL on that column. In a few days
we will see if this was the cause.
Thanks for the useful info eveyrone! Helped a lot!
Attila Wind
http://www.linkedin.com/in/attilaw
Mobile: +49 176 43556932
21.08.2020 11:04 keltezéssel, Alex Ott írta:
inserting null for any column will generate the tombstone (and you
can't have null for clustering column, except case when it's an empty
partition with static column).
if you're really inserting the new data, not overwriting existing one
- use UNSET instead of null
On Fri, Aug 21, 2020 at 10:45 AM Attila Wind <attilaw@swf.technology>
wrote:
Thanks a lot! I will process every pointers you gave - appreciated!
1. we do have collection column in that table but that is (we have
only 1 column) a frozen Map - so I guess "Tombstones are also
implicitly created any time you insert or update a row which has
an (unfrozen) collection column: list<>, map<> or set<>. This has
to be done in order to ensure the new write replaces any existing
collection entries." does not really apply here
2. "Isn’t it so that explicitly setting a column to NULL also
result in a tombstone"
Is this true for all columns? or just clustering key cols?
Because if for all cols (which would make sense maybe to me more)
then we found the possible reason.. :-)
As we do have an Integer coulmn there which is actually NULL often
(and so far in all cases)
Attila Wind
http://www.linkedin.com/in/attilaw
Mobile: +49 176 43556932
21.08.2020 09:49 keltezéssel, Oleksandr Shulgin írta:
On Fri, Aug 21, 2020 at 9:43 AM Tobias Eriksson
<tobias.eriks...@qvantel.com
<mailto:tobias.eriks...@qvantel.com>> wrote:
Isn’t it so that explicitly setting a column to NULL also
result in a tombstone
True, thanks for pointing that out!
Then as mentioned the use of list,set,map can also result in
tombstones
See
https://www.instaclustr.com/cassandra-collections-hidden-tombstones-and-how-to-avoid-them/
And A. Ott has already mentioned both these possible reasons :-)
--
Alex
--
With best wishes, Alex Ott
http://alexott.net/
Twitter: alexott_en (English), alexott (Russian)
