🕷️ Crawler Inspector

URL Lookup

Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 18 (from laksa070)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa018.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, meta_canonical AS meta_canonical, ml_categories_json AS ml_categories_json, ml_types_json AS ml_types_json, ml_intent_types_json AS ml_intent_types_json, meta_language AS meta_language, attrs_author AS attrs_author, ifNull(toUnixTimestamp(attrs_publish_time), 0) AS attrs_publish_time, ifNull(toUnixTimestamp(attrs_original_publish_time), 0) AS attrs_original_publish_time, ifNull(attrs_is_republished, 0) AS attrs_is_republished, ifNull(attrs_nr_words, 0) AS attrs_nr_words, ifNull(attrs_boilerpipe_nr_words, 0) AS attrs_boilerpipe_nr_words, ifNull(body_ext_links_number, 0) AS body_ext_links_number, ifNull(body_int_links_number, 0) AS body_int_links_number, ifNull(meta_nofollow, 0) AS meta_nofollow, ifNull(meta_noarchive, 0) AS meta_noarchive, ifNull(props_was_rendered, 0) AS props_was_rendered, ifNull(src_redirect, \'\') AS src_redirect, ifNull(download_time_msec, 0) AS download_time_msec, ifNull(download_ttfb_msec, 0) AS download_ttfb_msec, ifNull(download_size, 0) AS download_size FROM crawler3.page_info_local FINAL PREWHERE int_partition_id = 1 AND (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://math.stackexchange.com/questions/974228/error-correcting-codes-used-in-real-life\')), getAhrefsUnparsedNoserviceFromURL(\'https://math.stackexchange.com/questions/974228/error-correcting-codes-used-in-real-life\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/math.stackexchange.com\/questions\/974228\/error-correcting-codes-used-in-real-life","crawl_time":1775157465,"first_indexed_time":1438475208,"http_code":200,"src_unparsed":"com,stackexchange!math,\/questions\/974228\/error-correcting-codes-used-in-real-life s443","src_root_hash":"8045678284012640218","history_drop_reason":null,"meta_title":"coding theory - Error-correcting codes used in real life - Mathematics Stack Exchange","meta_descriptions":[],"meta_canonical":null,"ml_categories_json":"{\"\/Computers_and_Electronics\":818,\"\/Computers_and_Electronics\/Programming\":597,\"\/Science\":262,\"\/Computers_and_Electronics\/Programming\/Other\":188,\"\/Science\/Computer_Science\":159}","ml_types_json":"{\"\/Article\":965,\"\/Article\/Tutorial_or_Guide\":685}","ml_intent_types_json":"{\"Informational\":999}","meta_language":"en","attrs_author":null,"attrs_publish_time":1413334457,"attrs_original_publish_time":1413334457,"attrs_is_republished":0,"attrs_nr_words":"2374","attrs_boilerpipe_nr_words":"425","body_ext_links_number":46,"body_int_links_number":114,"meta_nofollow":0,"meta_noarchive":0,"props_was_rendered":1,"src_redirect":"","download_time_msec":187,"download_ttfb_msec":157,"download_size":43313}

3. Robots.txt Check

Query:

Response:

4. Spam/Ban Check

Query:

Response:

5. Seen Status Check

ℹ️ Skipped - page is already crawled

📍

LOCATION

Host 18 · Partition 1

laksa018

8045678284012640218

📄

INDEXABLE

✅

CRAWLED

2 months ago

🤖

ROBOTS ALLOWED

Page Info Filters

Filter	Status	Condition	Details
HTTP status	PASS	`download_http_code = 200`	HTTP 200
Age cutoff	PASS	`download_stamp > now() - 6 MONTH`	2.1 months ago
History drop	PASS	`isNull(history_drop_reason)`	No drop reason
Spam/ban	PASS	`fh_dont_index != 1 AND ml_spam_score = 0`	ml_spam_score=0
Canonical	PASS	`meta_canonical IS NULL OR = '' OR = src_unparsed`	Not set

Page Details

Property

Value

URL

https://math.stackexchange.com/questions/974228/error-correcting-codes-used-in-real-life

Last Crawled

2026-04-02 19:17:45 (2 months ago)

First Indexed

2015-08-02 00:26:48 (10 years ago)

HTTP Status Code

200

Content

Meta Title

coding theory - Error-correcting codes used in real life - Mathematics Stack Exchange

Meta Description

null

Meta Canonical

null

Boilerpipe Text

heavy column, fetched on demand

Markdown

heavy column, fetched on demand

Readable Markdown

heavy column, fetched on demand

ML Classification

ML Categories

/Computers_and_Electronics		81.8%
/Computers_and_Electronics/Programming		59.7%
/Science		26.2%
/Computers_and_Electronics/Programming/Other		18.8%
/Science/Computer_Science		15.9%

Raw JSON

{
    "/Computers_and_Electronics": 818,
    "/Computers_and_Electronics/Programming": 597,
    "/Science": 262,
    "/Computers_and_Electronics/Programming/Other": 188,
    "/Science/Computer_Science": 159
}

ML Page Types

/Article		96.5%
/Article/Tutorial_or_Guide		68.5%

Raw JSON

{
    "/Article": 965,
    "/Article/Tutorial_or_Guide": 685
}

ML Intent Types

Informational

99.9%

Raw JSON

{
    "Informational": 999
}

Content Metadata

Language

Author

null

Publish Time

2014-10-15 00:54:17 (11 years ago)

Original Publish Time

2014-10-15 00:54:17 (11 years ago)

Republished

Word Count (Total)

2,374

Word Count (Content)

425

Links

External Links

Internal Links

114

Technical SEO

Meta Nofollow

Meta Noarchive

JS Rendered

Yes

Redirect Target

null

Performance

Download Time (ms)

187

TTFB (ms)

157

Download Size (bytes)

43,313

Location

Host ID

18 (laksa018)

Partition ID

Root Hash

8045678284012640218

Unparsed URL

com,stackexchange!math,/questions/974228/error-correcting-codes-used-in-real-life s443