2 ms·
ack that anonymous user in internet said he couldn't make CLickhouse joins perform well in his case which he didn't describe
by riku_iki 3y ago
ack that anonymous user in internet said he couldn't make CLickhouse joins perform well in his case which he didn't describe
- biggestdummy 3y agoNot "that anonymous user." In my experience, avoiding Join statements is a common best practice for Clickhouse users seeking performant queries on large datasets. A couple examples... https://medium.com/datadenys/optimizing-star-schema-queries-with-in-queries-and-denormalization-cc281bbe19a5 https://medium.com/datadenys/optimizing-star-schema-queries-... https://posthog.com/blog/secrets-of-posthog-query-performance#whats-next https://posthog.com/blog/secrets-of-posthog-query-performanc...
- riku_iki 3y ago> avoiding Join statements is a common best practice for Clickhouse users seeking performant queries on large datasets its common best practice on any database, because if both joined tables don't fit memory, then merge join is O(nlogn) operation which indeed many times slower than querying denormalized schema, which will have linear execution time.