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michelin / snowflake-grafana-datasource

Snowflake Grafana datasource plugin enables the visual representation of Snowflake data within Grafana dashboards and manages alerts.
Apache License 2.0
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timeseries grafana maxdatapoints limit problem #48

Closed kranthikirang closed 1 year ago

kranthikirang commented 1 year ago

Grafana version: 9.4.7 Plugin Version: 1.4.1

currently we are limiting query size if the query is time series and maxDataPoints is set

https://github.com/michelin/snowflake-grafana-datasource/blob/master/pkg/query.go#LL218C5-L218C34

Below is the problem with an example data:

Given a table with three columns with time series data, the following behavior has been observed with Grafana 9.4.7 with michelin-snowflake-connector 1.4.1 +-----------------------+------------------+--------------------+ | Timestamp | Node | Measurement | +-----------------------+------------------+--------------------+ | 2023-05-17 00:00:00 | node A | 234 | +-----------------------+------------------+--------------------+ | 2023-05-17 00:00:00 | node B | 263 | +-----------------------+------------------+--------------------+ | 2023-05-17 00:00:00 | node C | 213 | +-----------------------+------------------+--------------------+ | 2023-05-17 00:05:00 | node A | 212 | +-----------------------+------------------+--------------------+ | 2023-05-17 00:05:00 | node B | 297 | +-----------------------+------------------+--------------------+ | 2023-05-17 00:05:00 | node C | 243 | +-----------------------+------------------+--------------------+

This results in 2 rows after the grafana timeseries transform: +-----------------------+------------------+-------------------+---------------+ | Timestamp | node A | node B | node C | +-----------------------+------------------+-------------------+---------------+ | 2023-05-17 00:00:00 | 234 | 263 | 213 | +-----------------------+------------------+-------------------+---------------+ | 2023-05-17 00:05:00 | 212 | 297 | 243 | +-----------------------+------------------+-------------------+---------------+

We are expecting 6 rows, but for the sake of example, if MaxDataPoints were set explicity to 4 (or implictly by panel width and timerange) the plugin adds “LIMIT 4” to the query and only fetches 4 rows, which results in missing samples:

+-----------------------+------------------+-------------------+---------------+ | Timestamp | node A | node B | node C | +-----------------------+------------------+-------------------+---------------+ | 2023-05-17 00:00:00 | 234 | 263 | 213 | +-----------------------+------------------+-------------------+---------------+ | 2023-05-17 00:05:00 | 212 | | | +-----------------------+------------------+-------------------+---------------+

kranthikirang commented 1 year ago

Could you please check https://github.com/michelin/snowflake-grafana-datasource/pull/50