Github user s1monw commented on a diff in the pull request:
https://github.com/apache/lucene-solr/pull/513#discussion_r239136654
--- Diff:
lucene/core/src/java/org/apache/lucene/index/FieldUpdatesBuffer.java ---
@@ -0,0 +1,280 @@
+/*
+ * 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.
+ */
+
+package org.apache.lucene.index;
+
+import java.io.IOException;
+import java.util.Arrays;
+
+import org.apache.lucene.util.ArrayUtil;
+import org.apache.lucene.util.Bits;
+import org.apache.lucene.util.BytesRef;
+import org.apache.lucene.util.BytesRefArray;
+import org.apache.lucene.util.BytesRefIterator;
+import org.apache.lucene.util.Counter;
+import org.apache.lucene.util.FixedBitSet;
+import org.apache.lucene.util.RamUsageEstimator;
+
+/**
+ * This class efficiently buffers numeric and binary field updates and
stores
+ * terms, values and metadata in a memory efficient way without creating
large amounts
+ * of objects. Update terms are stored without de-duplicating the update
term.
+ * In general we try to optimize for several use-cases. For instance we
try to use constant
+ * space for update terms field since the common case always updates on
the same field. Also for docUpTo
+ * we try to optimize for the case when updates should be applied to all
docs ie. docUpTo=Integer.MAX_VALUE.
+ * In other cases each update will likely have a different docUpTo.
+ * Along the same lines this impl optimizes the case when all updates have
a value. Lastly, if all updates share the
+ * same value for a numeric field we only store the value once.
+ */
+final class FieldUpdatesBuffer {
+ private static final long SELF_SHALLOW_SIZE =
RamUsageEstimator.shallowSizeOfInstance(FieldUpdatesBuffer.class);
+ private static final long STRING_SHALLOW_SIZE =
RamUsageEstimator.shallowSizeOfInstance(String.class);
+ private final Counter bytesUsed;
+ private int numUpdates = 1;
+ // we use a very simple approach and store the update term values
without de-duplication
+ // which is also not a common case to keep updating the same value more
than once...
+ // we might pay a higher price in terms of memory in certain cases but
will gain
+ // on CPU for those. We also save on not needing to sort in order to
apply the terms in order
+ // since by definition we store them in order.
+ private final BytesRefArray termValues;
+ private final BytesRefArray byteValues; // this will be null if we are
buffering numerics
+ private int[] docsUpTo;
+ private long[] numericValues; // this will be null if we are buffering
binaries
+ private FixedBitSet hasValues;
+ private String[] fields;
+ private final boolean isNumeric;
+
+ private FieldUpdatesBuffer(Counter bytesUsed, DocValuesUpdate
initialValue, int docUpTo, boolean isNumeric) {
+ this.bytesUsed = bytesUsed;
+ this.bytesUsed.addAndGet(SELF_SHALLOW_SIZE);
+ termValues = new BytesRefArray(bytesUsed);
+ termValues.append(initialValue.term.bytes);
+ fields = new String[] {initialValue.term.field};
+ bytesUsed.addAndGet(sizeOfString(initialValue.term.field));
+ docsUpTo = new int[] {docUpTo};
+ if (initialValue.hasValue == false) {
+ hasValues = new FixedBitSet(1);
+ bytesUsed.addAndGet(hasValues.ramBytesUsed());
+ }
+ this.isNumeric = isNumeric;
+ byteValues = isNumeric ? null : new BytesRefArray(bytesUsed);
+ }
+
+ private static long sizeOfString(String string) {
+ return STRING_SHALLOW_SIZE + (string.length() * Character.BYTES);
+ }
+
+ FieldUpdatesBuffer(Counter bytesUsed,
DocValuesUpdate.NumericDocValuesUpdate initialValue, int docUpTo) {
+ this(bytesUsed, initialValue, docUpTo, true);
+ if (initialValue.hasValue()) {
+ numericValues = new long[] {initialValue.getValue()};
+ } else {
+ numericValues = new long[] {0};
+ }
+ bytesUsed.addAndGet(Long.BYTES);
+ }
+
+ FieldUpdatesBuffer(Counter bytesUsed,
DocValuesUpdate.BinaryDocValuesUpdate initialValue, int docUpTo) {
+ this(bytesUsed, initialValue, docUpTo, false);
+ if (initialValue.hasValue()) {
+ byteValues.append(initialValue.getValue());
+ }
+ }
+
+ void add(String field, int docUpTo, int ord, boolean hasValue) {
+ if (fields[0].equals(field) == false || fields.length != 1 ) {
+ if (fields.length <= ord) {
+ String[] array = ArrayUtil.grow(fields, ord+1);
+ if (fields.length == 1) {
+ Arrays.fill(array, 1, ord, fields[0]);
+ }
+ bytesUsed.addAndGet((array.length - fields.length) *
RamUsageEstimator.NUM_BYTES_OBJECT_REF);
+ fields = array;
+ }
+ if (field != fields[0]) { // that's an easy win of not accounting if
there is an outlier
+ bytesUsed.addAndGet(sizeOfString(field));
+ }
+ fields[ord] = field;
+ }
+
+ if (docsUpTo[0] != docUpTo || docsUpTo.length != 1) {
+ if (docsUpTo.length <= ord) {
+ int[] array = ArrayUtil.grow(docsUpTo, ord+1);
+ if (docsUpTo.length == 1) {
+ Arrays.fill(array, 1, ord, docsUpTo[0]);
+ }
+ bytesUsed.addAndGet((array.length-docsUpTo.length) *
Integer.BYTES);
+ docsUpTo = array;
+ }
+ docsUpTo[ord] = docUpTo;
+ }
+
+ if (hasValue == false || hasValues != null) {
+ if (hasValues == null) {
+ hasValues = new FixedBitSet(ord+1);
+ hasValues.set(0, ord);
+ bytesUsed.addAndGet(hasValues.ramBytesUsed());
+ } else {
+ FixedBitSet fixedBitSet = FixedBitSet.ensureCapacity(hasValues,
ArrayUtil.oversize(ord + 1, 1));
--- End diff --
++ good catch
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