> For the complete documentation index, see [llms.txt](https://docs.postgresql.tw/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.postgresql.tw/15/client-interfaces/libpq-c-library/33.16.-the-connection-service-file.md).

# 34.17. The Connection Service File

## 34.17. The Connection Service File

The connection service file allows libpq connection parameters to be associated with a single service name. That service name can then be specified in a libpq connection string, and the associated settings will be used. This allows connection parameters to be modified without requiring a recompile of the libpq-using application. The service name can also be specified using the `PGSERVICE` environment variable.

Service names can be defined in either a per-user service file or a system-wide file. If the same service name exists in both the user and the system file, the user file takes precedence. By default, the per-user service file is named `~/.pg_service.conf`. On Microsoft Windows, it is named `%APPDATA%\postgresql\.pg_service.conf` (where `%APPDATA%` refers to the Application Data subdirectory in the user's profile). A different file name can be specified by setting the environment variable `PGSERVICEFILE`. The system-wide file is named `pg_service.conf`. By default it is sought in the `etc` directory of the PostgreSQL installation (use `pg_config --sysconfdir` to identify this directory precisely). Another directory, but not a different file name, can be specified by setting the environment variable `PGSYSCONFDIR`.

Either service file uses an “INI file” format where the section name is the service name and the parameters are connection parameters; see [Section 34.1.2](/15/client-interfaces/libpq-c-library/database-connection-control-functions.md#LIBPQ-PARAMKEYWORDS) for a list. For example:

```

# comment
[mydb]
host=somehost
port=5433
user=admin
```

An example file is provided in the PostgreSQL installation at `share/pg_service.conf.sample`.

Connection parameters obtained from a service file are combined with parameters obtained from other sources. A service file setting overrides the corresponding environment variable, and in turn can be overridden by a value given directly in the connection string. For example, using the above service file, a connection string `service=mydb port=5434` will use host `somehost`, port `5434`, user `admin`, and other parameters as set by environment variables or built-in defaults.

***

原文：[PostgreSQL 15.19 Documentation](/15/client-interfaces/libpq-c-library/33.16.-the-connection-service-file.md)（英文原文，待翻譯）


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation by asking a question.

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://docs.postgresql.tw/15/client-interfaces/libpq-c-library/33.16.-the-connection-service-file.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.