ektravel commented on code in PR #16491: URL: https://github.com/apache/druid/pull/16491#discussion_r1622592187
########## docs/release-info/migr-front-coded-dict.md: ########## @@ -0,0 +1,90 @@ +--- +id: migr-front-coded-dict +title: "Migration guide: front-coded dictionaries" +sidebar_label: Front-coded dictionaries +--- + +<!-- + ~ 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. +--> + +:::info +Front coding is an [experimental feature](../development/experimental.md) introduced in Druid 25.0.0. +::: + +Apache Druid encodes string columns into dictionaries for better compression. +Front coding is an incremental encoding strategy that lets you store STRING and [COMPLEX<json>](../querying/nested-columns.md) columns in Druid with minimal performance impact. +Front-coded dictionaries reduce storage and improve performance by optimizing for strings where the front part looks similar. +For example, if you are tracking website visits, most URLs start with `https://domain.xyz/`, and front coding is able to exploit this pattern for more optimal compression when storing such datasets. + +With front coding enabled, Druid tracks the length of common prefixes of values so that only the suffix is stored. Review Comment: Removed. -- 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: commits-unsubscr...@druid.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@druid.apache.org For additional commands, e-mail: commits-h...@druid.apache.org
