In this release, parallel hash join becomes the default join strategy, WITH FILL gets a STALENESS modifier, you can pre-warm the marks cache, and vec

ClickHouse Release 24.11

submited by

Style Pass

2024-12-14 10:30:05

In this release, parallel hash join becomes the default join strategy, WITH FILL gets a STALENESS modifier, you can pre-warm the marks cache, and vector search gets faster with the BFloat16 data type.

As always, we send a special welcome to all the new contributors in 24.11! ClickHouse's popularity is, in large part, due to the efforts of the community that contributes. Seeing that community grow is always humbling.

0xMihalich, Max Vostrikov, Payam Qorbanpour, Plasmaion, Roman Antonov, Romeo58rus, Zoe Steinkamp, kellytoole, ortyomka, qhsong, udiz, yun, Örjan Fors, Андрей

The parallel hash join algorithm is a variation of a hash join that splits the input data to build several hash tables concurrently in order to speed up the join at the expense of higher memory overhead. You can see a diagram of the algorithm's query pipeline below:

You can learn more about parallel hash join in the ClickHouse Joins Under the Hood - Hash Join, Parallel Hash Join, Grace Hash Join blog post.