asl3 commented on code in PR #53625: URL: https://github.com/apache/spark/pull/53625#discussion_r2651326873
########## common/utils/src/main/scala/org/apache/spark/util/UUIDv7Generator.scala: ########## @@ -0,0 +1,62 @@ +/* + * 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.spark.sql.util + +import java.time.Instant +import java.util.UUID + +import scala.util.Random + +object UUIDv7Generator { + + /** + * Follow the UUIDv7 specification defined in + * https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format#section-5.2 + */ + + private val random = new Random() + + /** + * Generate a UUIDv7 from the current time. + */ + def generate(): UUID = { + val now = Instant.now() + generateFrom(now.toEpochMilli, now.getNano) + } + + /** + * Deterministic UUIDv7 generation from epochMilli and nanos. + * Called by generate() and used for testing. + */ + def generateFrom(epochMilli: Long, nano: Int): UUID = { Review Comment: I updated to follow the same official RFC (originally had followed the [draft spec](https://datatracker.ietf.org/doc/html/draft-peabody-dispatch-new-uuid-format#section-5.2)). The major change, besides `nano`, is added monotonicity guarantee here: ``` public static UUID generate() { long timestamp = lastTimestamp.updateAndGet(last -> { long now = System.currentTimeMillis(); return now > last ? now : last + 1; }); return buildUUID(timestamp, ThreadLocalRandom.current().nextInt() & 0xFFF); } ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
