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Sorry if this is obvious, but... What is ClickHouse?

by andridk 5y ago

dm33tri 5y ago
In a nutshell: like MySQL but for analytic applications
rapsey 5y ago
You could clink on the link and find out.
amyjess 5y ago
Officially, it's a column-oriented database. This means that, internally, it stores columns together rather than rows together. In practice, it means that it's optimized for calculating analytics over large datasets. I've found, from personal experience, that it makes a good replacement for time-series databases, even though it's technically not a time-series database. My employer migrated our KPIs and other metrics from InfluxDB to ClickHouse a couple of years ago, and the drastic improvements in performance were well worth the time it took to migrate our data. It also helped that ClickHouse uses a subset of SQL, unlike InfluxDB which uses a superficially SQL-like but practically very different proprietary language.
- andridk 5y ago
  Thanks! Very informative
- ithkuil 5y ago
  You may be interested in https://github.com/influxdata/influxdb_iox https://github.com/influxdata/influxdb_iox Column store db, using the DataFusion SQL engine. Persistence using parquet files directly on object stores (e.g. S3) Still under development
  - swasheck 5y ago
    Every high-volume Influx/Grafana implementation I’ve used has been a disaster. I’m now at a place that uses ClickHouse and I can now see the utility of Grafana
    - sofixa 5y ago
      How so? I run a moderately sized InfluxDB stack (2x~2TB data) with Grafana, and it works pretty well.
    - ithkuil 5y ago
      The shape of the data matters. In particular the cardinality of the tags. If clickhouse works well for you, chances are that your use case will be well served by influxdb_iox too
- fnord77 5y ago
  from what I've read, it is not a column-oriented db. It's more like druid or pinot.
  - manigandham 5y ago
    Clickhouse/Druid/Pinot are all columnstores/column-oriented databases. Clickhouse is a relational engine while Druid/Pinot are a different (and older) design using heavy indexing and pre-aggregation. All of them store table data as per-column segments though which is a defining feature leading to high compression and I/O performance. There's also the badly named wide-column database type like Cassandra, but this is really just advanced or nested key/value rather than what people would consider "columns".

Sorry if this is obvious, but... What is ClickHouse?

dm33tri 5y ago

In a nutshell: like MySQL but for analytic applications

rapsey 5y ago

You could clink on the link and find out.

amyjess 5y ago

Officially, it's a column-oriented database. This means that, internally, it stores columns together rather than rows together. In practice, it means that it's optimized for calculating analytics over large datasets. I've found, from personal experience, that it makes a good replacement for time-series databases, even though it's technically not a time-series database. My employer migrated our KPIs and other metrics from InfluxDB to ClickHouse a couple of years ago, and the drastic improvements in performance were well worth the time it took to migrate our data. It also helped that ClickHouse uses a subset of SQL, unlike InfluxDB which uses a superficially SQL-like but practically very different proprietary language.

andridk 5y ago
Thanks! Very informative
ithkuil 5y ago
You may be interested in https://github.com/influxdata/influxdb_iox https://github.com/influxdata/influxdb_iox Column store db, using the DataFusion SQL engine. Persistence using parquet files directly on object stores (e.g. S3) Still under development
- swasheck 5y ago
  Every high-volume Influx/Grafana implementation I’ve used has been a disaster. I’m now at a place that uses ClickHouse and I can now see the utility of Grafana
  - sofixa 5y ago
    How so? I run a moderately sized InfluxDB stack (2x~2TB data) with Grafana, and it works pretty well.
  - ithkuil 5y ago
    The shape of the data matters. In particular the cardinality of the tags. If clickhouse works well for you, chances are that your use case will be well served by influxdb_iox too
fnord77 5y ago
from what I've read, it is not a column-oriented db. It's more like druid or pinot.
- manigandham 5y ago
  Clickhouse/Druid/Pinot are all columnstores/column-oriented databases. Clickhouse is a relational engine while Druid/Pinot are a different (and older) design using heavy indexing and pre-aggregation. All of them store table data as per-column segments though which is a defining feature leading to high compression and I/O performance. There's also the badly named wide-column database type like Cassandra, but this is really just advanced or nested key/value rather than what people would consider "columns".