🕷️ Crawler Inspector

URL Lookup

Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 39 (from laksa014)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa039.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 = 15 AND (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.studysmarter.co.uk/explanations/math/discrete-mathematics/error-correcting-codes/\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.studysmarter.co.uk/explanations/math/discrete-mathematics/error-correcting-codes/\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.studysmarter.co.uk\/explanations\/math\/discrete-mathematics\/error-correcting-codes\/","crawl_time":1775988702,"first_indexed_time":1710360521,"http_code":200,"src_unparsed":"uk,co,studysmarter!www,\/explanations\/math\/discrete-mathematics\/error-correcting-codes\/ s443","src_root_hash":"3738670086249643039","history_drop_reason":null,"meta_title":"Error Correcting Codes: Types & Applications | StudySmarter","meta_descriptions":["Error Correcting Codes: ✓ Basic Principles ✓ Applications ✓ StudySmarterOriginal!"],"meta_canonical":null,"ml_categories_json":"{\"\/Computers_and_Electronics\":648,\"\/Computers_and_Electronics\/Software\":352,\"\/Science\":303,\"\/Computers_and_Electronics\/Software\/Educational_Software\":296,\"\/Science\/Computer_Science\":189,\"\/Science\/Computer_Science\/Other\":134,\"\/Jobs_and_Education\":117,\"\/Jobs_and_Education\/Education\":117}","ml_types_json":"{\"\/Article\":977,\"\/Article\/Tutorial_or_Guide\":767}","ml_intent_types_json":"{\"Informational\":999}","meta_language":"en-gb","attrs_author":null,"attrs_publish_time":0,"attrs_original_publish_time":1710360521,"attrs_is_republished":0,"attrs_nr_words":"4389","attrs_boilerpipe_nr_words":"3056","body_ext_links_number":39,"body_int_links_number":116,"meta_nofollow":0,"meta_noarchive":0,"props_was_rendered":1,"src_redirect":"","download_time_msec":448,"download_ttfb_msec":428,"download_size":92427}

3. Robots.txt Check

Query:

Response:

4. Spam/Ban Check

Query:

Response:

5. Seen Status Check

ℹ️ Skipped - page is already crawled

📍

LOCATION

Host 39 · Partition 15

laksa039

3738670086249643039

📄

INDEXABLE

✅

CRAWLED

1 month 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`	1.7 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://www.studysmarter.co.uk/explanations/math/discrete-mathematics/error-correcting-codes/

Last Crawled

2026-04-12 10:11:42 (1 month ago)

First Indexed

2024-03-13 20:08:41 (2 years ago)

HTTP Status Code

200

Content

Meta Title

Error Correcting Codes: Types & Applications | StudySmarter

Meta Description

Error Correcting Codes: ✓ Basic Principles ✓ Applications ✓ StudySmarterOriginal!

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		64.8%
/Computers_and_Electronics/Software		35.2%
/Science		30.3%
/Computers_and_Electronics/Software/Educational_Software		29.6%
/Science/Computer_Science		18.9%
/Science/Computer_Science/Other		13.4%
/Jobs_and_Education		11.7%
/Jobs_and_Education/Education		11.7%

Raw JSON

{
    "/Computers_and_Electronics": 648,
    "/Computers_and_Electronics/Software": 352,
    "/Science": 303,
    "/Computers_and_Electronics/Software/Educational_Software": 296,
    "/Science/Computer_Science": 189,
    "/Science/Computer_Science/Other": 134,
    "/Jobs_and_Education": 117,
    "/Jobs_and_Education/Education": 117
}

ML Page Types

/Article		97.7%
/Article/Tutorial_or_Guide		76.7%

Raw JSON

{
    "/Article": 977,
    "/Article/Tutorial_or_Guide": 767
}

ML Intent Types

Informational

99.9%

Raw JSON

{
    "Informational": 999
}

Content Metadata

Language

en-gb

Author

null

Publish Time

not set

Original Publish Time

2024-03-13 20:08:41 (2 years ago)

Republished

Word Count (Total)

4,389

Word Count (Content)

3,056

Links

External Links

Internal Links

116

Technical SEO

Meta Nofollow

Meta Noarchive

JS Rendered

Yes

Redirect Target

null

Performance

Download Time (ms)

448

TTFB (ms)

428

Download Size (bytes)

92,427

Location

Host ID

39 (laksa039)

Partition ID

Root Hash

3738670086249643039

Unparsed URL

uk,co,studysmarter!www,/explanations/math/discrete-mathematics/error-correcting-codes/ s443