Github user jinfengni commented on a diff in the pull request:
https://github.com/apache/drill/pull/805#discussion_r111501238
--- Diff:
exec/java-exec/src/main/codegen/templates/CastVarBinaryInterval.java ---
@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+<@pp.dropOutputFile />
+
+<#list cast.types as type>
+<#if type.major == "VarBinaryInterval"> <#-- Template to convert from
VarBinary to Interval, IntervalYear, IntervalDay -->
+
+<@pp.changeOutputFile
name="/org/apache/drill/exec/expr/fn/impl/gcast/Cast${type.from}To${type.to}.java"
/>
+
+<#include "/@includes/license.ftl" />
+
+package org.apache.drill.exec.expr.fn.impl.gcast;
+
+import io.netty.buffer.ByteBuf;
+
+import org.apache.drill.exec.expr.DrillSimpleFunc;
+import org.apache.drill.exec.expr.annotations.FunctionTemplate;
+import
org.apache.drill.exec.expr.annotations.FunctionTemplate.NullHandling;
+import org.apache.drill.exec.expr.annotations.Output;
+import org.apache.drill.exec.expr.annotations.Param;
+import org.apache.drill.exec.expr.holders.IntervalDayHolder;
+import org.apache.drill.exec.expr.holders.IntervalHolder;
+import org.apache.drill.exec.expr.holders.IntervalYearHolder;
+import org.apache.drill.exec.expr.holders.VarBinaryHolder;
+
+/*
+ * This class is generated using freemarker and the ${.template_name}
template.
+ */
+@SuppressWarnings("unused")
+@FunctionTemplate(name = "cast${type.to?upper_case}",
+ scope = FunctionTemplate.FunctionScope.SIMPLE,
+ nulls = NullHandling.NULL_IF_NULL)
+public class Cast${type.from}To${type.to} implements DrillSimpleFunc {
+
+ @Param ${type.from}Holder in;
+ @Output ${type.to}Holder out;
+
+ public void setup() {
+ }
+
+ public void eval() {
+ final byte[] buf = new byte[in.end - in.start];
+ in.buffer.getBytes(in.start, buf, 0, in.end - in.start);
+ <#if type.to == "Interval">
+ out.months =
org.apache.drill.exec.store.parquet.ParquetReaderUtility.getIntFromLEBytes(buf,
0);
--- End diff --
I'm a bit confused. Are you assuming VarBinary is encoded as 3 int values
: # of months, # of days and # of millisecon? If varbinary is encoded in such
way, which is parquet used to encode logical type "interval", why do we have to
cast ?
My understanding is varbinary looks similar to varchar, except that the
former contains byte while the latter contains character.
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