> ## 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

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*                                                                                      |