Imprints for Joining
From MonetDBJump to navigationJump to search
- Use same binning method as in Column Imprints paper
- Perform initial join on two tables R, S. Make "join imprint" on smallest table R.
- For each cache line of data in R, create an imprint of S with bits set for the bins of S which join with that cache line.
- Compress and construct dictionary as in Column Imprints paper
Performing a Join Operation
- Join "join imprint" of R with column imprint of S with equality being bitwise or.
- Use result as input to final join
- Maybe this is cheaper overall?
- If the tables are nicely correlated, the imprint should be compressible
- Size of index should be much less than even the size of R
- Should be possibly to efficiently combine original column imprints with "join imprint" in select + join operations
- Updateability: simple as in column imprints.