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phorge-phorge/src/applications/search/engineextension/PhabricatorNgramsIndexEngineExtension.php
epriestley 96fe8c0b83 Implement basic ngram search for Owners Package names
Summary:
Ref T9979. This uses ngrams (specifically, trigrams) to build a reasonably efficient index for substring matching. Specifically, for a package like "Example", with ID 123, we store rows like this:

```
< ex, 123>
<exa, 123>
<xam, 123>
<amp, 123>
<mpl, 123>
<ple, 123>
<le , 123>
```

When the user searches for `exam`, we join this table for packages with tokens `exa` and `xam`. MySQL can do this a lot more efficiently than it can process a `LIKE "%exam%"` query against a huge table.

When the user searches for a one-letter or two-letter string, we only search the beginnings of words. This is probably what they want, the only thing we can do quickly, and a reasonable/expected behavior for typeaheads.

Test Plan:
  - Ran storage upgrades and search indexer.
  - Searched for stuff with "name contains".
  - Used typehaead and got sensible results.
  - Searched for `aabbccddeeffgghhiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz` and saw only 16 joins.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9979

Differential Revision: https://secure.phabricator.com/D14846
2015-12-22 08:00:33 -08:00

34 lines
762 B
PHP

<?php
final class PhabricatorNgramsIndexEngineExtension
extends PhabricatorIndexEngineExtension {
const EXTENSIONKEY = 'ngrams';
public function getExtensionName() {
return pht('Ngrams Engine');
}
public function getIndexVersion($object) {
$ngrams = $object->newNgrams();
$map = mpull($ngrams, 'getValue', 'getNgramKey');
ksort($map);
$serialized = serialize($map);
return PhabricatorHash::digestForIndex($serialized);
}
public function shouldIndexObject($object) {
return ($object instanceof PhabricatorNgramsInterface);
}
public function indexObject(
PhabricatorIndexEngine $engine,
$object) {
foreach ($object->newNgrams() as $ngram) {
$ngram->writeNgram($object->getID());
}
}
}