From oak-issues-return-67713-archive-asf-public=cust-asf.ponee.io@jackrabbit.apache.org Wed Jan 16 12:42:14 2019 Return-Path: X-Original-To: archive-asf-public@cust-asf.ponee.io Delivered-To: archive-asf-public@cust-asf.ponee.io Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by mx-eu-01.ponee.io (Postfix) with SMTP id 2FC98180675 for ; Wed, 16 Jan 2019 12:42:14 +0100 (CET) Received: (qmail 82783 invoked by uid 500); 16 Jan 2019 11:42:08 -0000 Mailing-List: contact oak-issues-help@jackrabbit.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: oak-dev@jackrabbit.apache.org Delivered-To: mailing list oak-issues@jackrabbit.apache.org Received: (qmail 82755 invoked by uid 99); 16 Jan 2019 11:42:08 -0000 Received: from pnap-us-west-generic-nat.apache.org (HELO spamd3-us-west.apache.org) (209.188.14.142) by apache.org (qpsmtpd/0.29) with ESMTP; Wed, 16 Jan 2019 11:42:08 +0000 Received: from localhost (localhost [127.0.0.1]) by spamd3-us-west.apache.org (ASF Mail Server at spamd3-us-west.apache.org) with ESMTP id CACFD180D9F for ; Wed, 16 Jan 2019 11:42:07 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at spamd3-us-west.apache.org X-Spam-Flag: NO X-Spam-Score: -109.501 X-Spam-Level: X-Spam-Status: No, score=-109.501 tagged_above=-999 required=6.31 tests=[ENV_AND_HDR_SPF_MATCH=-0.5, KAM_ASCII_DIVIDERS=0.8, RCVD_IN_DNSWL_MED=-2.3, SPF_PASS=-0.001, USER_IN_DEF_SPF_WL=-7.5, USER_IN_WHITELIST=-100] autolearn=disabled Received: from mx1-lw-eu.apache.org ([10.40.0.8]) by localhost (spamd3-us-west.apache.org [10.40.0.10]) (amavisd-new, port 10024) with ESMTP id pU2KqUxu2Krj for ; Wed, 16 Jan 2019 11:42:05 +0000 (UTC) Received: from mailrelay1-us-west.apache.org (mailrelay1-us-west.apache.org [209.188.14.139]) by mx1-lw-eu.apache.org (ASF Mail Server at mx1-lw-eu.apache.org) with ESMTP id EE89D60F75 for ; Wed, 16 Jan 2019 11:42:04 +0000 (UTC) Received: from jira-lw-us.apache.org (unknown [207.244.88.139]) by mailrelay1-us-west.apache.org (ASF Mail Server at mailrelay1-us-west.apache.org) with ESMTP id E2B33E2678 for ; Wed, 16 Jan 2019 11:42:03 +0000 (UTC) Received: from jira-lw-us.apache.org (localhost [127.0.0.1]) by jira-lw-us.apache.org (ASF Mail Server at jira-lw-us.apache.org) with ESMTP id ED6822564A for ; Wed, 16 Jan 2019 11:42:02 +0000 (UTC) Date: Wed, 16 Jan 2019 11:42:02 +0000 (UTC) From: "Davide Giannella (JIRA)" To: oak-issues@jackrabbit.apache.org Message-ID: In-Reply-To: References: Subject: [jira] [Closed] (OAK-7379) Lucene Index: per-column selectivity, assume 5 unique entries MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-JIRA-FingerPrint: 30527f35849b9dde25b450d4833f0394 [ https://issues.apache.org/jira/browse/OAK-7379?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Davide Giannella closed OAK-7379. --------------------------------- bulk close 1.10.0 > Lucene Index: per-column selectivity, assume 5 unique entries > ------------------------------------------------------------- > > Key: OAK-7379 > URL: https://issues.apache.org/jira/browse/OAK-7379 > Project: Jackrabbit Oak > Issue Type: Improvement > Components: lucene, query > Reporter: Thomas Mueller > Assignee: Thomas Mueller > Priority: Major > Labels: candidate_oak_1_8 > Fix For: 1.9.0, 1.10.0 > > > Currently, if a query has a property restriction of the form "property = x", and the property is indexed in a Lucene property index, the estimated cost is the index is the number of documents indexed for that property. This is a very conservative estimate, it means all documents have the same value. So the cost is relatively high for that index. > In almost all cases, there are many distinct values for a property. Rarely there are few values, or a skewed distribution where one value contains most documents. But in almost all cases there are more than 5 distinct values. > I think it makes sense to use 5 as the default value. It is still conservative (cost of the index is high), but much better than now. -- This message was sent by Atlassian JIRA (v7.6.3#76005)