@title Cluster: Search
@group cluster

Overview
========

You can configure Phabricator to connect to one or more fulltext search
services.

By default, Phabricator will use MySQL for fulltext search. This is suitable
for most installs. However, alternate engines are supported.


Configuring Search Services
===========================

To configure search services, adjust the `cluster.search` configuration
option. This option contains a list of one or more fulltext search services,
like this:

```lang=json
[
  {
    "type": "...",
    "hosts": [
      ...
    ],
    "roles": {
      "read": true,
      "write": true
    }
  }
]
```

When a user makes a change to a document, Phabricator writes the updated
document into every configured, writable fulltext service.

When a user issues a query, Phabricator tries configured, readable services
in order until it is able to execute the query successfully.

These options are supported by all service types:

| Key | Description |
|---|---|
| `type` | Constant identifying the service type, like `mysql`.
| `roles` | Dictionary of role settings, for enabling reads and writes.
| `hosts` | List of hosts for this service.

Some service types support additional options.

Available Service Types
=======================

These service types are supported:

| Service | Key | Description |
|---|---|---|
| MySQL | `mysql` | Default MySQL fulltext index.
| Elasticsearch | `elasticsearch` | Use an external Elasticsearch service


Fulltext Service Roles
======================

These roles are supported:

| Role | Key | Description
|---|---|---|
| Read | `read` | Allows the service to be queried when users search.
| Write | `write` | Allows documents to be published to the service.


Specifying Hosts
================

The `hosts` key should contain a list of dictionaries, each specifying the
details of a host. A service should normally have one or more hosts.

When an option is set at the service level, it serves as a default for all
hosts. It may be overridden by changing the value for a particular host.


Service Type: MySQL
==============

The `mysql` service type does not require any configuration, and does not
need to have hosts specified. This service uses the builtin database to
index and search documents.

A typical `mysql` service configuration looks like this:

```lang=json
{
  "type": "mysql"
}
```


Service Type: Elasticsearch
======================

The `elasticsearch` sevice type supports these options:

| Key | Description |
|---|---|
| `protocol` | Either `"http"` (default) or `"https"`.
| `port` | Elasticsearch TCP port.
| `version` | Elasticsearch version, either `2` or `5` (default).
| `path` | Path for the index. Defaults to `/phabriator`. Advanced.

A typical `elasticsearch` service configuration looks like this:

```lang=json
{
  "type": "elasticsearch",
  "hosts": [
    {
      "protocol": "http",
      "host": "127.0.0.1",
      "port": 9200
    }
  ]
}
```

Monitoring Search Services
==========================

You can monitor fulltext search in {nav Config > Search Servers}. This
interface shows you a quick overview of services and their health.

The table on this page shows some basic stats for each configured service,
followed by the configuration and current status of each host.


Rebuilding Indexes
==================

After adding new search services, you will need to rebuild document indexes
on them. To do this, first initialize the services:

```
phabricator/ $ ./bin/search init
```

This will perform index setup steps and other one-time configuration.

To populate documents in all indexes, run this command:

```
phabricator/ $ ./bin/search index --force --background --type all
```

This initiates an exhaustive rebuild of the document indexes. To get a more
detailed list of indexing options available, run:

```
phabricator/ $ ./bin/search help index
```


Advanced Example
================

This is a more advanced example which shows a configuration with multiple
different services in different roles. In this example:

  - Phabricator is using an Elasticsearch 2 service as its primary fulltext
    service.
  - An Elasticsearch 5 service is online, but only receiving writes.
  - The MySQL service is serving as a backup if Elasticsearch fails.

This particular configuration may not be very useful. It is primarily
intended to show how to configure many different options.


```lang=json
[
  {
    "type": "elasticsearch",
    "version": 2,
    "hosts": [
      {
        "host": "elastic2.mycompany.com",
        "port": 9200,
        "protocol": "http"
      }
    ]
  },
  {
    "type": "elasticsearch",
    "version": 5,
    "hosts": [
      {
        "host": "elastic5.mycompany.com",
        "port": 9789,
        "protocol": "https"
        "roles": {
          "read": false,
          "write": true
        }
      }
    ]
  },
  {
    "type": "mysql"
  }
]
```
