[NUTCH-721] Fetcher2 Slow

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.0
• Fix Version/s: 1.1
• Component/s: fetcher

Environment

Fedora Core r6, Kernel 2.6.22-14, jdk1.6.0_12

• Assignee: Dogacan Guney
• Reporter: Roger Dunk
• Created: 17/Mar/09 20:29
• Updated: 25/Aug/09 05:46
• Resolved: 25/Aug/09 05:46

Description

Fetcher2 fetches far more slowly than Fetcher1.

Config options:
fetcher.threads.fetch = 80
fetcher.threads.per.host = 80
fetcher.server.delay = 0
generate.max.per.host = 1

With a queue size of ~40,000, the result is:

activeThreads=80, spinWaiting=79, fetchQueues.totalSize=0

with maybe a download of 1 page per second.

Runing with -noParse makes little difference.

CPU load average is around 0.2. With Fetcher1 CPU load is around 2.0 - 3.0

Hosts already cached by local caching NS appear to download quickly upon a re-fetch, so possible issue relating to NS lookups, however all things being equal Fetcher1 runs fast without pre-caching hosts.