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This commit is contained in:
Tom Lane 2011-01-09 15:24:22 -05:00
parent 4448917d51
commit 327b257682
1 changed files with 5 additions and 4 deletions
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9
contrib/btree_gin/btree_gin.c
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@ -394,10 +394,11 @@ static TypeInfo TypeInfo_varbit = {true, leftmostvalue_varbit, bitcmp};
GIN_SUPPORT(varbit)
/*
* Numeric type hasn't applicable left-most value, so NULL
* is used for that. NULL will never be an argument for a C-level
* numeric function except gin_numeric_cmp and it will not be stored
* somewhere and it could not be returned in any user SQL query.
* Numeric type hasn't a real left-most value, so we use PointerGetDatum(NULL)
* (*not* a SQL NULL) to represent that. We can get away with that because
* the value returned by our leftmostvalue function will never be stored in
* the index nor passed to anything except our compare and prefix-comparison
* functions. The same trick could be used for other pass-by-reference types.
*/
#define NUMERIC_IS_LEFTMOST(x) ((x) == NULL)