in aggregation code
The patch disables padding that forces hasher to calculate over the whole 2k buffer. This patch also moves hashing code
into the common place where it belongs.
This change fixes:
MCOL-4462 CAST(varchar_expr AS DECIMAL(M,N)) returns a wrong result
MCOL-4500 Bit functions processing throws internally trying to cast char into decimal representation
MCOL-4532 CAST(AS DECIMAL) returns a garbage for large values
Also, this change makes string-to-decimal conversion 5-10 times faster,
depending on exact data.
Performance implemenent is achieved by the fact that (unlike in the old
implementation), the new version does not do any "string" object copying.
A non-JOIN condition like `WHERE c1=c2` (with c1 and c2 being columns of the
same table) was not collation-aware yet after the main patches for MCOL-4064.
Additionally fixing StrFilterCmd::compare*() to address this.
