ignite-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Vladimir Ozerov (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (IGNITE-6079) SQL: implement base table statistics
Date Wed, 16 Aug 2017 11:55:00 GMT

     [ https://issues.apache.org/jira/browse/IGNITE-6079?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Vladimir Ozerov updated IGNITE-6079:
------------------------------------
    Labels: performance  (was: )

> SQL: implement base table statistics
> ------------------------------------
>
>                 Key: IGNITE-6079
>                 URL: https://issues.apache.org/jira/browse/IGNITE-6079
>             Project: Ignite
>          Issue Type: Task
>          Components: sql
>    Affects Versions: 2.1
>            Reporter: Vladimir Ozerov
>              Labels: performance
>             Fix For: 2.2
>
>
> Ignite lacks cost-based optimizer what doesn't allow us to build efficient execution
plans. Let's start moving in this direction.
> The ticket is about creating local statistics for tables. In the first phase they will
not be shared between nodes, neither they will participate in query optimization. The ultimate
goal of this ticket is to start gathering some info in the background and provide necessary
internal infrastructure and APIs for that.
> *1. API*
> Let's start with a single method {{GridQueryProcessor.rebuildStatistics()}}, which will
build stats for all existing tables.
> *2. Infrastructure*
> - Statistics are transient, not persisted
> - We need a background worker which will re-build them on regular basis and replace old
with new using copy-on-write approach
> - Statistics are created for indexed (i.e. sorted) columns 
> - Sampling should be used to avoid full table scan
> *3. Statistics types*
> - Height-based: the whole range is split into N pieces, so that exactly M/N entries are
located between X and X+1 piece, where M is number of records
> One statistics type should be enough in the first iteration.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Mime
View raw message