> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chronosphere.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Migration notes for SignalFx (Splunk) to PromQL

> Learn how to translate SignalFx queries to PromQL for Chronosphere Observability Platform.

There are several key differences between SignalFx (Splunk) and PromQL of which to be
aware when migrating queries to Chronosphere:

* *Rollups* in SignalFx are used to aggregate data points within a single time
  series. With Chronosphere, rollups are [defined only on ingest](/control/shaping/shape-metrics/rules),
  and not at query time. However, PromQL offers a
  [set of functions](https://prometheus.io/docs/prometheus/latest/querying/functions/#aggregation_over_time)
  for aggregating individual time series over time.
* *Analytics* in SignalFx are the equivalent to functions in PromQL.

## Equivalent function list

| SignalFx             | PromQL                               | Notes                                                                                       |
| -------------------- | ------------------------------------ | ------------------------------------------------------------------------------------------- |
| Absolute value       | `abs()`                              | *none*                                                                                      |
| Bottom               | `bottomk()`                          | *none*                                                                                      |
| Ceiling              | `ceil()`                             | *none*                                                                                      |
| Count                | `count()`, `count_over_time()`       | *none*                                                                                      |
| Delta                | `delta()`                            | *none*                                                                                      |
| EWMA and Double EWMA | `holt_winters()`                     | `holt_winters()` is similar to, but not exactly like, Exponentially Weighted Moving Average |
| Exclude              | Use comparators                      | *none*                                                                                      |
| Floor                | `floor()`                            | *none*                                                                                      |
| Integrate            | `rate()`                             | *none*                                                                                      |
| LN - Log (natural)   | `ln()`                               | *none*                                                                                      |
| Log10                | `log10()`                            | *none*                                                                                      |
| Maximum              | `max()`, `max_over_time()`           | *none*                                                                                      |
| Mean                 | `avg()`, `avg_over_time()`           | *none*                                                                                      |
| Minimum              | `min()`, `min_over_time()`           | *none*                                                                                      |
| Percentile           | `quantile()`, `quantile_over_time()` | Use histogram\_quantile() with Histograms                                                   |
| Power                | Use operators                        | *none*                                                                                      |
| Rate of change       | `rate()`                             | *none*                                                                                      |
| Scale                | Use operators                        | *none*                                                                                      |
| Square root          | `sqrt()`                             | *none*                                                                                      |
| Standard deviation   | `stddev()`, `stddev_over_time()`     | *none*                                                                                      |
| Sum                  | `sum()`, `sum_over_time()`           | *none*                                                                                      |
| Timeshift            | offset                               | *none*                                                                                      |
| Top                  | `topk()`                             | *none*                                                                                      |
| Variance             | `stdvar()`, `stdvar_over_time()`     | *none*                                                                                      |