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From "Semyon Semyonov (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (NUTCH-2368) Variable generate.max.count and fetcher.server.delay
Date Fri, 03 Nov 2017 14:12:00 GMT

     [ https://issues.apache.org/jira/browse/NUTCH-2368?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Semyon Semyonov updated NUTCH-2368:
-----------------------------------
    Attachment: NUTCH-2368_RESTAPI_Fix.patch

There was a problem with REST API client, because API uses different Run method and this method
didn't include the hostdb parameter.

The path fixes this problem.
It may have some problems with the line offset, because I'm not so fluent with SVN yet.

> Variable generate.max.count and fetcher.server.delay
> ----------------------------------------------------
>
>                 Key: NUTCH-2368
>                 URL: https://issues.apache.org/jira/browse/NUTCH-2368
>             Project: Nutch
>          Issue Type: Improvement
>          Components: generator
>    Affects Versions: 1.12
>            Reporter: Markus Jelsma
>            Assignee: Markus Jelsma
>            Priority: Major
>             Fix For: 1.14
>
>         Attachments: NUTCH-2368.patch, NUTCH-2368.patch, NUTCH-2368.patch, NUTCH-2368.patch,
NUTCH-2368.patch, NUTCH-2368.patch, NUTCH-2368.patch, NUTCH-2368.patch, NUTCH-2368.patch,
NUTCH-2368_RESTAPI_Fix.patch
>
>
> In some cases we need to use host specific characteristics in determining crawl speed
and bulk sizes because with our (Openindex) settings we can just recrawl host with up to 800k
urls.
> This patch solves the problem by introducing the HostDB to the Generator and providing
powerful Jexl expressions. Check these two expressions added to the Generator:
> {code}
> -Dgenerate.max.count.expr='
> if (unfetched + fetched > 800000) {
>   return (conf.getInt("fetcher.timelimit.mins", 12) * 60) / ((pct95._rs_ + 500) / 1000)
* conf.getInt("fetcher.threads.per.queue", 1)
> } else {
>   return conf.getDouble("generate.max.count", 300);
> }'
> -Dgenerate.fetch.delay.expr='
> if (unfetched + fetched > 800000) {
>   return (pct95._rs_ + 500);
> } else {
>   return conf.getDouble("fetcher.server.delay", 1000)
> }'
> {code}
> For each large host: select as many records as possible that are possible to fetch based
on number of threads, 95th percentile response time of the fetch limit. Or: queueMaxCount
= (timelimit / resonsetime) * numThreads.
> The second expression just follows up to that, settings the crawlDelay of the fetch queue.



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