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The following commit(s) were added to refs/heads/master by this push:
new 4290e5a Cache selectors in QueryableIndexColumnSelectorFactory.
(#7216)
4290e5a is described below
commit 4290e5ae7a9be0cfff68bddae0501602c5ed1c73
Author: Gian Merlino <[email protected]>
AuthorDate: Mon Mar 11 11:33:02 2019 -0700
Cache selectors in QueryableIndexColumnSelectorFactory. (#7216)
For selectors with internal caches (like SingleScanTimeDimensionSelector,
SingleLongInputCachingExpressionColumnValueSelector, etc) we can get a perf
boost and memory usage decrease by sharing selectors.
---
.../QueryableIndexColumnSelectorFactory.java | 93 +++++++++++++---------
1 file changed, 57 insertions(+), 36 deletions(-)
diff --git
a/processing/src/main/java/org/apache/druid/segment/QueryableIndexColumnSelectorFactory.java
b/processing/src/main/java/org/apache/druid/segment/QueryableIndexColumnSelectorFactory.java
index c0b5ee5..ec5ee1d 100644
---
a/processing/src/main/java/org/apache/druid/segment/QueryableIndexColumnSelectorFactory.java
+++
b/processing/src/main/java/org/apache/druid/segment/QueryableIndexColumnSelectorFactory.java
@@ -30,6 +30,7 @@ import org.apache.druid.segment.column.ValueType;
import org.apache.druid.segment.data.ReadableOffset;
import javax.annotation.Nullable;
+import java.util.HashMap;
import java.util.Map;
/**
@@ -45,8 +46,14 @@ class QueryableIndexColumnSelectorFactory implements
ColumnSelectorFactory
private final Closer closer;
protected final ReadableOffset offset;
+ // Share Column objects, since they cache decompressed buffers internally,
and we can avoid recomputation if the
+ // same column is used by more than one part of a query.
private final Map<String, BaseColumn> columnCache;
+ // Share selectors too, for the same reason that we cache columns (they may
cache things internally).
+ private final Map<DimensionSpec, DimensionSelector> dimensionSelectorCache;
+ private final Map<String, ColumnValueSelector> valueSelectorCache;
+
QueryableIndexColumnSelectorFactory(
QueryableIndex index,
VirtualColumns virtualColumns,
@@ -62,16 +69,23 @@ class QueryableIndexColumnSelectorFactory implements
ColumnSelectorFactory
this.closer = closer;
this.offset = offset;
this.columnCache = columnCache;
+ this.dimensionSelectorCache = new HashMap<>();
+ this.valueSelectorCache = new HashMap<>();
}
@Override
public DimensionSelector makeDimensionSelector(DimensionSpec dimensionSpec)
{
- if (virtualColumns.exists(dimensionSpec.getDimension())) {
- return virtualColumns.makeDimensionSelector(dimensionSpec, this);
- }
-
- return
dimensionSpec.decorate(makeDimensionSelectorUndecorated(dimensionSpec));
+ return dimensionSelectorCache.computeIfAbsent(
+ dimensionSpec,
+ spec -> {
+ if (virtualColumns.exists(spec.getDimension())) {
+ return virtualColumns.makeDimensionSelector(spec, this);
+ }
+
+ return spec.decorate(makeDimensionSelectorUndecorated(spec));
+ }
+ );
}
private DimensionSelector makeDimensionSelectorUndecorated(DimensionSpec
dimensionSpec)
@@ -93,20 +107,10 @@ class QueryableIndexColumnSelectorFactory implements
ColumnSelectorFactory
return
type.makeNumericWrappingDimensionSelector(makeColumnValueSelector(dimension),
extractionFn);
}
- BaseColumn column = columnCache.computeIfAbsent(dimension, d -> {
- BaseColumn col = columnHolder.getColumn();
- if (col instanceof DictionaryEncodedColumn) {
- return closer.register(col);
- } else {
- // Return null from the lambda in computeIfAbsent() results in no
recorded value in the columnCache and
- // the column variable is set to null.
- return null;
- }
- });
-
- if (column instanceof DictionaryEncodedColumn) {
- //noinspection unchecked
- return ((DictionaryEncodedColumn<String>)
column).makeDimensionSelector(offset, extractionFn);
+ final DictionaryEncodedColumn column = getCachedColumn(dimension,
DictionaryEncodedColumn.class);
+
+ if (column != null) {
+ return column.makeDimensionSelector(offset, extractionFn);
} else {
return DimensionSelector.constant(null, extractionFn);
}
@@ -115,24 +119,41 @@ class QueryableIndexColumnSelectorFactory implements
ColumnSelectorFactory
@Override
public ColumnValueSelector<?> makeColumnValueSelector(String columnName)
{
- if (virtualColumns.exists(columnName)) {
- return virtualColumns.makeColumnValueSelector(columnName, this);
- }
-
- BaseColumn column = columnCache.computeIfAbsent(columnName, name -> {
- ColumnHolder holder = index.getColumnHolder(name);
- if (holder != null) {
- return closer.register(holder.getColumn());
- } else {
- return null;
- }
- });
+ return valueSelectorCache.computeIfAbsent(
+ columnName,
+ name -> {
+ if (virtualColumns.exists(columnName)) {
+ return virtualColumns.makeColumnValueSelector(columnName, this);
+ }
+
+ BaseColumn column = getCachedColumn(columnName, BaseColumn.class);
+
+ if (column != null) {
+ return column.makeColumnValueSelector(offset);
+ } else {
+ return NilColumnValueSelector.instance();
+ }
+ }
+ );
+ }
- if (column != null) {
- return column.makeColumnValueSelector(offset);
- } else {
- return NilColumnValueSelector.instance();
- }
+ @Nullable
+ @SuppressWarnings("unchecked")
+ private <T extends BaseColumn> T getCachedColumn(final String columnName,
final Class<T> clazz)
+ {
+ return (T) columnCache.computeIfAbsent(
+ columnName,
+ name -> {
+ ColumnHolder holder = index.getColumnHolder(name);
+ if (holder != null &&
clazz.isAssignableFrom(holder.getColumn().getClass())) {
+ return closer.register(holder.getColumn());
+ } else {
+ // Return null from the lambda in computeIfAbsent() results in no
recorded value in the columnCache and
+ // the column variable is set to null.
+ return null;
+ }
+ }
+ );
}
@Override
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