Don't push down functions by default#245
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Much better than before. Good to have this cleaned up to avoid the legacy of the fork from postgres_fdw.
Seems like we could use a few more tests though, yes?
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heavily expanded test suite. also fixed deparsing bytea, as ch doesn't support pg bytea syntax for strings |
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Make builtin function pushdown opt-in: Postgres builtins now ship to ClickHouse only when explicitly mapped, so name or signature differences cannot silently alter results. Add explicit mappings for `mod`, `pow`/`power`, `bit_count(bytea)`, and `reverse(text)` (→ `reverseUTF8`) to retain previously working pushdowns. Fix `editDistance`, `length(text)` and `strpos(text, text)` pushdown to map to `lengthUTF8` and `positionUTF8` rather than ClickHouse's byte-counting `length` and `position`, matching Postgres character semantics. Stop pushing down `asin`, `acos`, `atanh`, and `acosh`: Postgres raises an error on out-of-range input where ClickHouse returns `NaN`. Evaluating locally preserves Postgres semantics. Add comprehensive tests for all of these behaviors. Signed-off-by: David E. Wheeler <david.wheeler@clickhouse.com>
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Explicitly add functions which were falling through correctly by default
Include mapping mod/pow/power/bit_count/reverse/bit_and/bit_or/bit_xor
length(text)in PG is actuallylengthUTF8in CHasin/acos/atanh/acosh not pushed down for now since they need range checks: on PG out-of-range is error, whereas on CH out-of-range returns NaN