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From "MIYAKAWA Taku (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PIG-3215) [piggybank] Add LTSVLoader to load LTSV (Labeled Tab-separated Values) files
Date Wed, 24 Apr 2013 23:53:14 GMT

    [ https://issues.apache.org/jira/browse/PIG-3215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13641196#comment-13641196

MIYAKAWA Taku commented on PIG-3215:

Jonathan, sorry for the delay. As long as I see, you have not made a post about the issue
at dev@pig.apache.org. May I make a post instead of you?
> [piggybank] Add LTSVLoader to load LTSV (Labeled Tab-separated Values) files
> ----------------------------------------------------------------------------
>                 Key: PIG-3215
>                 URL: https://issues.apache.org/jira/browse/PIG-3215
>             Project: Pig
>          Issue Type: New Feature
>          Components: piggybank
>            Reporter: MIYAKAWA Taku
>            Assignee: MIYAKAWA Taku
>              Labels: piggybank
>         Attachments: LTSVLoader-6.html, LTSVLoader.html, PIG-3215-6.patch, PIG-3215.patch
> LTSV, or Labeled Tab-separated Values format is now getting popular in Japan for log
files, especially of web servers. The goal of this jira is to add LTSVLoader in PiggyBank
to load LTSV files.
> LTSV is based on TSV thus columns are separated by tab characters. Additionally each
of columns includes a label and a value, separated by ":" character.
> Read about LTSV on http://ltsv.org/.
> h4. Example LTSV file (access.log)
> Columns are separated by tab characters.
> {noformat}
> host:host1.example.org	req:GET /index.html	ua:Opera/9.80
> host:host1.example.org	req:GET /favicon.ico	ua:Opera/9.80
> host:pc.example.com	req:GET /news.html	ua:Mozilla/5.0
> {noformat}
> h4. Usage 1: Extract fields from each line
> Users can specify an input schema and get columns as Pig fields.
> This example loads the LTSV file shown in the previous section.
> {code}
> -- Parses the access log and count the number of lines
> -- for each pair of the host column and the ua column.
> access = LOAD 'access.log' USING org.apache.pig.piggybank.storage.LTSVLoader('host:chararray,
> grouped_access = GROUP access BY (host, ua);
> count_for_host_ua = FOREACH grouped_access GENERATE group.host, group.ua, COUNT(access);
> DUMP count_for_host_ua;
> {code}
> The below text will be printed out.
> {noformat}
> (host1.example.org,Opera/9.80,2)
> (pc.example.com,Firefox/5.0,1)
> {noformat}
> h4. Usage 2: Extract a map from each line
> Users can get a map for each LTSV line. The key of a map is a label of the LTSV column.
The value of a map comes from characters after ":" in the LTSV column.
> {code}
> -- Parses the access log and projects the user agent field.
> access = LOAD 'access.log' USING org.apache.pig.piggybank.storage.LTSVLoader() AS (m:map[]);
> user_agent = FOREACH access GENERATE m#'ua' AS ua;
> DUMP user_agent;
> {code}
> The below text will be printed out.
> {noformat}
> (Opera/9.80)
> (Opera/9.80)
> (Firefox/5.0)
> {noformat}

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