# Performance Monitor Data Archiving

**Which are the database tables to be queried for performance data?**

Here are the details that might help you extract reports by connecting to the database:

- The resources polled for data collection are stored in the table **polleddata**, and each polled data is assigned an **ID**. The name of the device in which these resources are polled is stored in the **AGENT** field. The following query will list the resource name (which is the polled-data), the resource id, and the agent (device) name:

  ```sql
  select name,id,agent from polleddata;
  ```

- The data collected on polling these resources is stored in the **STATSDATA** tables. The data is periodically archived for easy reporting and maintenance. The value of ID field in polleddata is stored as **POLLID** in the STATSDATA table. So, for a given device, the data collected for a particular resource can be retrieved using the following query assuming the POLLID is 413:

  ```sql
  select * from STATSDATA3_5_2018 where pollid=413;
  ```

- The data archiving is structured as follows:

  All the collected raw data is in a table called `STATSDATA`. Assume the data collection interval is 15 mins. So, in an hour, there are 4 values collected. Once every hour, these 4 values are averaged to one value in the `STATSDATA_HOURLY` table. Every day, the values in the `STATSDATA_HOURLY` table are averaged to the `STATSDATA_DAILY` table.

The data in the raw table, i.e., `STATSDATA` table, is maintained for 7 days by default and can be incremented to a maximum of 15 days. In the `_HOURLY` table, the data is maintained for 30 days by default and can be incremented to a maximum of 90 days. Similarly, the data in the `_DAILY` table is maintained for 365 days and can be pushed up to 3650 days maximum. This maintenance can be configured from **Settings → General Settings → Database Maintenance**.

> **Note:**
>
> The data used for displaying performance graphs will be controlled by both the **Database Maintenance Settings** and the **Graph Display Settings**. Make sure the values provided in Graph Display Settings are less than the corresponding value in Database Maintenance settings to ensure graphs are displayed properly.
>
> For example, if the Detailed raw data retention time is set to **7 days** and the Detailed statistics retention limit in the Graph Display Settings is set to **8 days**, there won't be enough data from the Detailed table for OpManager to display graphs, and so the data from the Hourly table will be used instead.