Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/1060#discussion_r158196813
--- Diff: exec/vector/src/main/codegen/templates/NullableValueVectors.java
---
@@ -51,6 +57,17 @@
public final class ${className} extends BaseDataValueVector implements
<#if type.major == "VarLen">VariableWidth<#else>FixedWidth</#if>Vector,
NullableVector {
private static final org.slf4j.Logger logger =
org.slf4j.LoggerFactory.getLogger(${className}.class);
+ /**
+ * Optimization to set contiguous values nullable state in a bulk
manner; cannot define this array
+ * within the Mutator class as Java doesn't allow static initialization
within a non static inner class.
+ */
+ private static final int DEFINED_VALUES_ARRAY_LEN = 1 << 10;
--- End diff --
This array is to set the "bits" vector to a set value? Nullable vectors can
be used only in in the top level (or in an array of maps). At the top level, a
batch can have, at most, 64K values. Do we need an array of 10,000,000,000
bytes if our limit is 64K?
Also, how long a run of set values do we expect? Can we use a shorter
array, but use it multiple times in the (very rare) cases in which we use a
nullable type to represent long runs on non-null values?
(Granted that, to be conservative, *ALL* vectors should be nullable since
we never know if the next file in a scan might be missing some column and we
need to fill in a long run of nulls...)
---
