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Implement approx_distinct for CHAR type #11101

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Merged
arhimondr merged 1 commit into from
Jul 20, 2018
Merged

Implement approx_distinct for CHAR type #11101

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9 changes: 9 additions & 0 deletions presto-main/src/main/java/com/facebook/presto/type/CharOperators.java
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@
import static com.facebook.presto.spi.function.OperatorType.LESS_THAN;
import static com.facebook.presto.spi.function.OperatorType.LESS_THAN_OR_EQUAL;
import static com.facebook.presto.spi.function.OperatorType.NOT_EQUAL;
import static com.facebook.presto.spi.function.OperatorType.XX_HASH_64;
import static com.facebook.presto.spi.type.Chars.compareChars;

public final class CharOperators
Expand Down Expand Up @@ -101,6 +102,14 @@ public static long hashCode(@SqlType("char(x)") Slice value)
return XxHash64.hash(value);
}

@LiteralParameters("x")
@ScalarOperator(XX_HASH_64)
@SqlType(StandardTypes.BIGINT)
public static long xxHash64(@SqlType("char(x)") Slice slice)
{
return XxHash64.hash(slice);
}

@LiteralParameters({"x"})
@ScalarOperator(IS_DISTINCT_FROM)
@SqlType(StandardTypes.BOOLEAN)
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4 changes: 4 additions & 0 deletions presto-tests/src/main/java/com/facebook/presto/tests/AbstractTestAggregations.java
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Expand Up @@ -720,6 +720,10 @@ public void testApproximateCountDistinct()
assertQuery("SELECT approx_distinct(CAST(custkey AS VARCHAR)) FROM orders", "SELECT 1036");
assertQuery("SELECT approx_distinct(CAST(custkey AS VARCHAR), 0.023) FROM orders", "SELECT 1036");

// test char
assertQuery("SELECT approx_distinct(CAST(CAST(custkey AS VARCHAR) AS CHAR(20))) FROM orders", "SELECT 1036");
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@findepi findepi Jul 20, 2018

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i guess CAST(custkey AS CHAR(20)) is not enough?

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@arhimondr arhimondr Jul 20, 2018

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No, there is no direct cast operator

assertQuery("SELECT approx_distinct(CAST(CAST(custkey AS VARCHAR) AS CHAR(20)), 0.023) FROM orders", "SELECT 1036");

// test varbinary
assertQuery("SELECT approx_distinct(to_utf8(CAST(custkey AS VARCHAR))) FROM orders", "SELECT 1036");
assertQuery("SELECT approx_distinct(to_utf8(CAST(custkey AS VARCHAR)), 0.023) FROM orders", "SELECT 1036");
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