---
title: Overview | Tiger Data Docs
description: Handle missing data in time-series queries
---

Most analytics start by rolling raw events into fixed windows with `time_bucket()`. That works until a window is empty because sampling was irregular or a collector failed. Gapfilling inserts placeholder rows so timelines stay contiguous; you then interpolate or carry values forward as needed.

- For more information about how gapfilling works, read the [gapfilling blog](https://www.tigerdata.com/blog/sql-functions-for-time-series-analysis).
- For more information about gapfilling and interpolation API calls, see the [hyperfunction API documentation](/docs/reference/timescaledb/hyperfunctions/time_bucket_gapfill/time_bucket_gapfill/index.md).