[CALCITE-3954] Always compare types using equals#1942
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danny0405 merged 1 commit intoapache:masterfrom Apr 27, 2020
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[CALCITE-3954] Always compare types using equals#1942danny0405 merged 1 commit intoapache:masterfrom
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hsyuan
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You must also change RelDataTypeImpl.equals.
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Yep, thanks for the reminder ~ |
Current interning of types use weak references. Change from MUST intern to SHOULD intern, and always compare types using equals. We clearly want to do some interning, especially within a query, so that there aren't hundreds of copies of the same record type all over the place. But if people don't intern, or intern in different query-specific caches, then the logic will still work. If equals is written using the standard template ```java return this == o || o instanceof TheType && field1 == o.field1 && field2 == o.field2 ``` (that is, avoiding deep comparison if possible) then the performance will be pretty much the same.
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Current interning of types use weak references.
Change from MUST intern to SHOULD intern, and always
compare types using equals.
We clearly want to do some interning, especially within a query, so that
there aren't hundreds of copies of the same record type all over the
place. But if people don't intern, or intern in different query-specific
caches, then the logic will still work.
If equals is written using the standard template
(that is, avoiding deep comparison if possible) then the performance
will be pretty much the same.