The second crawl of 2013 is now available! In late November, we published the data from the first crawl of 2013 (see previous blog post for more detail on that dataset). The new dataset was collected at the end of 2013, contains approximately 2.3 billion webpages and is 148TB in size. The new data is located in the commoncrawl bucket at /crawl-data/CC-MAIN-2013-48/
In 2013, we made changes to our crawling and post-processing systems. As detailed in the previous blog post, we switched file formats to the international standard WARC and WAT files. We also began using Apache Nutch to crawl – stay tuned for an upcoming blog post on our use of Nutch. The new crawling method relies heavily on the generous data donations from blekko and we are extremely grateful forongoing support!
In 2014 we plan to crawl much more frequently and publish fresh datasets at least once a month.
Erratum:
WAT data: repeated WARC and HTTP headers are not preserved
Repeated HTTP and WARC headers were not represented in the JSON data in WAT files. When a header was repeated adding a further value of that header, only the last value was stored and other values were lost. This issues was fixed with CC-MAIN-2024-51, see ia-web-commons#18. All WAT files from CC-MAIN-2013-20 until CC-MAIN-2024-46 are affected.
Erratum:
Erroneous title field in WAT records
The "Title" extracted in WAT records to the JSON path `Envelope > Payload-Metadata > HTTP-Response-Metadata > HTML-Metadata > Head > Title` is not the content included in the <title> element in the HTML header (<head> element) if the page contains further <title> elements in the page body. The content of the last <title> element is written to the WAT "Title". This bug was observed if the HTML page includes embedded SVG graphics.
The issue was reported by the user Robert Waksmunski:
- https://groups.google.com/g/common-crawl/c/ZrPFdY3pPA4/m/s5D_8wCJAAAJ
- WAT extractor: Document title bug ia-web-commons#36
...and was fixed for CC-MAIN-2024-42 by commoncrawl/ia-web-commons#37.
This erratum affects all crawls from CC-MAIN-2013-20 until CC-MAIN-2024-38.
Erratum:
Charset Detection Bug in WET Records
The charset detection required to properly transform non-UTF-8 HTML pages in WARC files into WET records didn't work before November 2016 due to a bug in IIPC Web Archive Commons (see the related issue in the CC fork of Apache Nutch). There should be significantly fewer errors in all subsequent crawls. Originally discussed here in Google Groups.
Erratum:
Missing Language Classification
Starting with crawl CC-MAIN-2018-39 we added a language classification field (‘content-languages’) to the columnar indexes, WAT files, and WARC metadata for all subsequent crawls. The CLD2 classifier was used, and includes up to three languages per document. We use the ISO-639-3 (three-character) language codes.
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