# Performance Schema file\_instances Table

## Description

The `file_instances` table lists instances of instruments seen by the Performance Schema when executing file I/O instrumentation, and the associated files. Only files that have been opened, and that have not been deleted, will be listed in the table.

The [performance\_schema\_max\_file\_instances](/docs/server/reference/system-tables/performance-schema/performance-schema-system-variables.md#performance_schema_max_file_instances) system variable specifies the maximum number of instrumented file objects.

| Column      | Description                                                                                   |
| ----------- | --------------------------------------------------------------------------------------------- |
| FILE\_NAME  | File name.                                                                                    |
| EVENT\_NAME | Instrument name associated with the file.                                                     |
| OPEN\_COUNT | Open handles on the file. A value of greater than zero means that the file is currently open. |

## Example

```sql
SELECT * FROM performance_schema.file_instances WHERE OPEN_COUNT>0;
+----------------------------------------------------+--------------------------------------+------------+
| FILE_NAME                                          | EVENT_NAME                           | OPEN_COUNT |
+----------------------------------------------------+--------------------------------------+------------+
| /var/log/mysql/mariadb-bin.index                   | wait/io/file/sql/binlog_index        |          1 |
| /var/lib/mysql/ibdata1                             | wait/io/file/innodb/innodb_data_file |          2 |
| /var/lib/mysql/ib_logfile0                         | wait/io/file/innodb/innodb_log_file  |          2 |
| /var/lib/mysql/ib_logfile1                         | wait/io/file/innodb/innodb_log_file  |          2 |
| /var/lib/mysql/mysql/gtid_slave_pos.ibd            | wait/io/file/innodb/innodb_data_file |          3 |
| /var/lib/mysql/mysql/innodb_index_stats.ibd        | wait/io/file/innodb/innodb_data_file |          3 |
| /var/lib/mysql/mysql/innodb_table_stats.ibd        | wait/io/file/innodb/innodb_data_file |          3 |
...
```

<sub>*This page is licensed: CC BY-SA / Gnu FDL*</sub>

{% @marketo/form formId="4316" %}


---

# 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://mariadb.com/docs/server/reference/system-tables/performance-schema/performance-schema-tables/performance-schema-file_instances-table.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.