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SQL: Remove "useFallback" feature.#7567

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fjy merged 1 commit intoapache:masterfrom
gianm:sql-no-fallback
Apr 29, 2019
Merged

SQL: Remove "useFallback" feature.#7567
fjy merged 1 commit intoapache:masterfrom
gianm:sql-no-fallback

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@gianm gianm commented Apr 28, 2019

This feature allows Calcite's Bindable interpreter to be bolted on
top of Druid queries and table scans. I think it should be removed for
a few reasons:

  1. It is not recommended for production anyway, because it generates
    unscalable query plans (e.g. it will plan a join into two table scans
    and then try to do the entire join in memory on the broker).
  2. It doesn't work with Druid-specific SQL functions, like TIME_FLOOR,
    REGEXP_EXTRACT, APPROX_COUNT_DISTINCT, etc.
  3. It makes the SQL planning code needlessly complicated.

With SQL coming out of experimental status soon, it's a good opportunity
to remove this feature.

This feature allows Calcite's Bindable interpreter to be bolted on
top of Druid queries and table scans. I think it should be removed for
a few reasons:

1. It is not recommended for production anyway, because it generates
unscalable query plans (e.g. it will plan a join into two table scans
and then try to do the entire join in memory on the broker).
2. It doesn't work with Druid-specific SQL functions, like TIME_FLOOR,
REGEXP_EXTRACT, APPROX_COUNT_DISTINCT, etc.
3. It makes the SQL planning code needlessly complicated.

With SQL coming out of experimental status soon, it's a good opportunity
to remove this feature.
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2 participants