[
https://issues.apache.org/jira/browse/BEAM-11997?focusedWorklogId=721261&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-721261
]
ASF GitHub Bot logged work on BEAM-11997:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 04/Feb/22 23:46
Start Date: 04/Feb/22 23:46
Worklog Time Spent: 10m
Work Description: pabloem commented on a change in pull request #15549:
URL: https://github.com/apache/beam/pull/15549#discussion_r799884605
##########
File path:
sdks/java/io/redis/src/main/java/org/apache/beam/sdk/io/redis/RedisCursor.java
##########
@@ -0,0 +1,161 @@
+/*
+ * 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.beam.sdk.io.redis;
+
+import static
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.Serializable;
+import java.nio.ByteBuffer;
+import java.util.Objects;
+import javax.annotation.Nonnull;
+import org.apache.beam.sdk.coders.BigEndianLongCoder;
+import org.apache.beam.sdk.io.range.ByteKey;
+import
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.annotations.VisibleForTesting;
+import org.checkerframework.checker.nullness.qual.Nullable;
+
+public class RedisCursor implements Comparable<RedisCursor>, Serializable {
+
+ private final String cursor;
+ private final long dbSize;
+ private final boolean isStart;
+
+ public static final ByteKey ZERO_KEY = ByteKey.of(0x00);
+ // The zero cursor that represents the start position is represented as
ByteKey.of(0x00)
+ public static final RedisCursor ZERO_CURSOR = RedisCursor.of("0", 8, true);
+ // The zero cursor that represents the start position is represented as
ByteKey.EMPTY
+ public static final RedisCursor END_CURSOR = RedisCursor.of("0", 8, false);
+
+ public static RedisCursor of(String cursor, long dbSize, boolean isStart) {
+ return new RedisCursor(cursor, dbSize, isStart);
+ }
+
+ private RedisCursor(String cursor, long dbSize, boolean isStart) {
+ this.cursor = cursor;
+ this.dbSize = dbSize;
+ this.isStart = isStart;
+ }
+
+ /**
+ * {@link RedisCursor} implements {@link Comparable
Comparable<RedisCursor>} by transforming
+ * the cursors to an index of the Redis table.
+ */
+ @Override
+ public int compareTo(@Nonnull RedisCursor other) {
+ checkNotNull(other, "other");
+ if ("0".equals(cursor) && "0".equals(other.cursor)) {
+ if (isStart && !other.isStart()) {
+ return -1;
+ } else if (!isStart && other.isStart()) {
+ return 1;
+ } else {
+ return 0;
+ }
+ }
+ return Long.compare(Long.parseLong(cursor), Long.parseLong(other.cursor));
+ }
+
+ @Override
+ public boolean equals(@Nullable Object o) {
+ if (this == o) {
+ return true;
+ }
+ if (o == null || getClass() != o.getClass()) {
+ return false;
+ }
+ RedisCursor that = (RedisCursor) o;
+ return dbSize == that.dbSize && isStart == that.isStart &&
Objects.equals(cursor, that.cursor);
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(cursor, dbSize, isStart);
+ }
+
+ public String getCursor() {
+ return cursor;
+ }
+
+ public long getDbSize() {
+ return dbSize;
+ }
+
+ public boolean isStart() {
+ return isStart;
+ }
+
+ /*
+ In order to write the functions that converts to and from a Redis cursor
and a ByteKey the following article and
+ its sources were used as reference as they explain in detail how a Redis
cursor is formed and how to transform it to
+ a sequential value that represents the current position of the scan cursor
in Redis tables.
+ https://engineering.q42.nl/redis-scan-cursor/
+ */
+ @VisibleForTesting
+ static ByteKey redisCursorToByteKey(RedisCursor cursor) {
+ if ("0".equals(cursor.getCursor())) {
+ if (cursor.isStart()) {
+ return ByteKey.of(0x00);
+ } else {
+ return ByteKey.EMPTY;
+ }
+ }
+ int nBits = getTablePow(cursor.getDbSize());
+ long cursorLong = Long.parseLong(cursor.getCursor());
+ long reversed = shiftBits(cursorLong, nBits);
+ BigEndianLongCoder coder = BigEndianLongCoder.of();
Review comment:
maybe create this coder only once. Perhaps add a member variable
INSTANCE to the class BigEndianLongCoder, so that we will only create one
instance, and have better performance
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Issue Time Tracking
-------------------
Worklog Id: (was: 721261)
Time Spent: 11h 20m (was: 11h 10m)
> Implement RedisIO on top of Splittable DoFn
> -------------------------------------------
>
> Key: BEAM-11997
> URL: https://issues.apache.org/jira/browse/BEAM-11997
> Project: Beam
> Issue Type: Improvement
> Components: io-java-redis
> Reporter: Boyuan Zhang
> Assignee: Miguel Anzo
> Priority: P2
> Time Spent: 11h 20m
> Remaining Estimate: 0h
>
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