3 ms·
Where clause is the worst possible use case for GPU: GPUs don't tolerate branches or non-coalesced memory access all that well, and WHERE executes a ton of bran
by throwaway-1209 9y ago
Where clause is the worst possible use case for GPU: GPUs don't tolerate branches or non-coalesced memory access all that well, and WHERE executes a ton of branches. Even so, things seem to be faster. Go figure.
- ris 9y agoI think it hugely depends on what your WHERE clause is.
- throwaway-1209 9y agoI guess if your where clause is very selective, you could avoid the hit since the same branch is taken by all threads in a warp. But then there are better approaches such as BRIN indexes, RLE and dictionary encoding with which you don't even touch the data that doesn't match your clause.