# pg\_stat\_statements

{% hint style="info" %}
This extension is a prerequisite when using Datasentinel.
{% endhint %}

Once the settings are configured, there is no further action required. \
Resetting **pg\_stat\_statements** is unnecessary.

Datasentinel collects activity metrics for all queries at regular intervals to allow detailed analyzes on the graphical interface.

## **Installation**

This extension is part of the official PostgreSQL contrib package.\
Refer to the [documentation](https://www.postgresql.org/docs/current/pgstatstatements.html) for more information

{% hint style="danger" %}
To be installed in the internal database named **postgres**
{% endhint %}

### Modify `postgresql.conf`

{% hint style="info" %}
Add **`pg_stat_statements`** to **`shared_preload_libraries`** parameter
{% endhint %}

* Add the following lines

<pre class="language-apache"><code class="lang-apache"><strong>#
</strong><strong># Track all statements
</strong>pg_stat_statements.track = all
#
# Optional, not necessary for Datasentinel to save pg_stat_statements.
pg_stat_statements.save = false
#
# The extension's maximum number of tracked statements should be reduced from its default 5000 value 
# (e.g. 2000) as Datasentinel collects metrics at regular intervals.
pg_stat_statements.max = 2000
#
# Since postgresql 14
compute_query_id = on
#
# log IO timing
track_io_timing=on
</code></pre>

{% hint style="info" %}
A new parameter **`compute_query_id`** has been added since PostgreSQL 14.\
This is a configuration parameter enabling computation of a query identifier, which can be displayed via `pg_stat_activity` , in `EXPLAIN` output or in log output if configured in log\_line\_prefix .&#x20;

For optimal utilization of Datasentinel, we advise configuring this parameter accordingly.

```sql
compute_query_id = on
```

{% endhint %}

{% hint style="info" %}
The **Agent version 3.2, which was released in February 2023**, introduces the [Collection level](about:blank/installation/collection_level.html#collection-level) feature allowing you to filter metrics collected from the extension
{% endhint %}

{% hint style="danger" %}
You see lots of utility commands (other than SELECT, INSERT, UPDATE, DELETE) in `pg_stat_statements,`

Especially  if you are using XA type distributed transactions, PREPARE TRANSACTION, COMMIT TRANSACTION, ROLLBACK TRANSACTION queries are not normalized by pg\_stat\_statements

You can disable their collect by setting this parameter:

```sql
pg_stat_statements.track_utility = off
```

{% endhint %}

### Reload Conf

* connect as a superuser

```sql
SELECT pg_reload_conf();
```

### Create Extension

* connect to the internal database named **postgres** with superuser privileges

```sql
CREATE EXTENSION pg_stat_statements;
```

### Check Extension

```sql
SELECT current_database(), extname from pg_extension where extname ='pg_stat_statements';
current_database |      extname
------------------+--------------------
postgres         | pg_stat_statements
(1 row)
```

```sql
// Ensure the returned count is greater than zero
select count(*) from pg_stat_statements
```


---

# Agent Instructions: Querying This Documentation

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

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.datasentinel.io/manual/getting-started/postgresql-clusters/extensions/pg_stat_statements.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.