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Diffstat (limited to 'doc/development/elasticsearch.md')
| -rw-r--r-- | doc/development/elasticsearch.md | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/doc/development/elasticsearch.md b/doc/development/elasticsearch.md index c8c70fa7216..94b3796f6e9 100644 --- a/doc/development/elasticsearch.md +++ b/doc/development/elasticsearch.md @@ -64,20 +64,25 @@ All indexing after the initial one is done via `ElasticIndexerWorker` (sidekiq j Search queries are generated by the concerns found in [ee/app/models/concerns/elastic](https://gitlab.com/gitlab-org/gitlab-ee/tree/master/ee/app/models/concerns/elastic). These concerns are also in charge of access control, and have been a historic source of security bugs so please pay close attention to them! ## Existing Analyzers/Tokenizers/Filters + These are all defined in https://gitlab.com/gitlab-org/gitlab-ee/blob/master/ee/lib/elasticsearch/git/model.rb ### Analyzers + #### `path_analyzer` + Used when indexing blobs' paths. Uses the `path_tokenizer` and the `lowercase` and `asciifolding` filters. Please see the `path_tokenizer` explanation below for an example. #### `sha_analyzer` + Used in blobs and commits. Uses the `sha_tokenizer` and the `lowercase` and `asciifolding` filters. Please see the `sha_tokenizer` explanation later below for an example. #### `code_analyzer` + Used when indexing a blob's filename and content. Uses the `whitespace` tokenizer and the filters: `code`, `edgeNGram_filter`, `lowercase`, and `asciifolding` The `whitespace` tokenizer was selected in order to have more control over how tokens are split. For example the string `Foo::bar(4)` needs to generate tokens like `Foo` and `bar(4)` in order to be properly searched. @@ -85,15 +90,19 @@ The `whitespace` tokenizer was selected in order to have more control over how t Please see the `code` filter for an explanation on how tokens are split. #### `code_search_analyzer` + Not directly used for indexing, but rather used to transform a search input. Uses the `whitespace` tokenizer and the `lowercase` and `asciifolding` filters. ### Tokenizers + #### `sha_tokenizer` + This is a custom tokenizer that uses the [`edgeNGram` tokenizer](https://www.elastic.co/guide/en/elasticsearch/reference/5.5/analysis-edgengram-tokenizer.html) to allow SHAs to be searcheable by any sub-set of it (minimum of 5 chars). -example: +Example: `240c29dc7e` becomes: + - `240c2` - `240c29` - `240c29d` @@ -102,21 +111,26 @@ example: - `240c29dc7e` #### `path_tokenizer` + This is a custom tokenizer that uses the [`path_hierarchy` tokenizer](https://www.elastic.co/guide/en/elasticsearch/reference/5.5/analysis-pathhierarchy-tokenizer.html) with `reverse: true` in order to allow searches to find paths no matter how much or how little of the path is given as input. -example: +Example: `'/some/path/application.js'` becomes: + - `'/some/path/application.js'` - `'some/path/application.js'` - `'path/application.js'` - `'application.js'` ### Filters + #### `code` -Uses a [Pattern Capture token filter](https://www.elastic.co/guide/en/elasticsearch/reference/5.5/analysis-pattern-capture-tokenfilter.html) to split tokens into more easily searched versions of themselves. + +Uses a [Pattern Capture token filter](https://www.elastic.co/guide/en/elasticsearch/reference/5.5/analysis-pattern-capture-tokenfilter.html) to split tokens into more easily searched versions of themselves. Patterns: + - `"(\\p{Ll}+|\\p{Lu}\\p{Ll}+|\\p{Lu}+)"`: captures CamelCased and lowedCameCased strings as separate tokens - `"(\\d+)"`: extracts digits - `"(?=([\\p{Lu}]+[\\p{L}]+))"`: captures CamelCased strings recursively. Ex: `ThisIsATest` => `[ThisIsATest, IsATest, ATest, Test]` @@ -126,6 +140,7 @@ Patterns: - `'\/?([^\/]+)(?=\/|\b)'`: separate path terms `like/this/one` #### `edgeNGram_filter` + Uses an [Edge NGram token filter](https://www.elastic.co/guide/en/elasticsearch/reference/5.5/analysis-edgengram-tokenfilter.html) to allow inputs with only parts of a token to find the token. For example it would turn `glasses` into permutations starting with `gl` and ending with `glasses`, which would allow a search for "`glass`" to find the original token `glasses` ## Gotchas @@ -140,13 +155,13 @@ Uses an [Edge NGram token filter](https://www.elastic.co/guide/en/elasticsearch/ You might get an error such as ``` -[2018-10-31T15:54:19,762][WARN ][o.e.c.r.a.DiskThresholdMonitor] [pval5Ct] - flood stage disk watermark [95%] exceeded on - [pval5Ct7SieH90t5MykM5w][pval5Ct][/usr/local/var/lib/elasticsearch/nodes/0] free: 56.2gb[3%], +[2018-10-31T15:54:19,762][WARN ][o.e.c.r.a.DiskThresholdMonitor] [pval5Ct] + flood stage disk watermark [95%] exceeded on + [pval5Ct7SieH90t5MykM5w][pval5Ct][/usr/local/var/lib/elasticsearch/nodes/0] free: 56.2gb[3%], all indices on this node will be marked read-only ``` -This is because you've exceeded the disk space threshold - it thinks you don't have enough disk space left, based on the default 95% threshold. +This is because you've exceeded the disk space threshold - it thinks you don't have enough disk space left, based on the default 95% threshold. In addition, the `read_only_allow_delete` setting will be set to `true`. It will block indexing, `forcemerge`, etc @@ -158,16 +173,16 @@ Add this to your `elasticsearch.yml` file: ``` # turn off the disk allocator -cluster.routing.allocation.disk.threshold_enabled: false +cluster.routing.allocation.disk.threshold_enabled: false ``` _or_ ``` # set your own limits -cluster.routing.allocation.disk.threshold_enabled: true +cluster.routing.allocation.disk.threshold_enabled: true cluster.routing.allocation.disk.watermark.flood_stage: 5gb # ES 6.x only -cluster.routing.allocation.disk.watermark.low: 15gb +cluster.routing.allocation.disk.watermark.low: 15gb cluster.routing.allocation.disk.watermark.high: 10gb ``` |