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

# General questions about ClickHouse

> Index page listing general questions about ClickHouse

| Page | Description |
| - | - |
| [What is a columnar database?](/docs/resources/support-center/knowledge-base/general-faqs/columnar-database) | Explainer on what a columnar database is. |
| [Does ClickHouse support frequent, concurrent queries?](/docs/resources/support-center/knowledge-base/general-faqs/concurrency) | Information about concurrent query support in ClickHouse. |
| [Does ClickHouse have a cost-based optimizer?](/docs/resources/support-center/knowledge-base/general-faqs/cost-based) | Information about ClickHouse's query optimizer. |
| [Does ClickHouse support data lakes?](/docs/resources/support-center/knowledge-base/general-faqs/datalake) | Information about ClickHouse data lake support. |
| [What does "ClickHouse" mean?](/docs/resources/support-center/knowledge-base/general-faqs/dbms-naming) | Explainer on the meaning of the name "ClickHouse". |
| [What are the 3rd-party dependencies for running ClickHouse?](/docs/resources/support-center/knowledge-base/general-faqs/dependencies) | Information about ClickHouse third-party dependencies. |
| [Does ClickHouse support distributed JOIN?](/docs/resources/support-center/knowledge-base/general-faqs/distributed-join) | Information about distributed JOIN support in ClickHouse. |
| [Does ClickHouse support federated queries?](/docs/resources/support-center/knowledge-base/general-faqs/federated) | Information about federated query support in ClickHouse. |
| [How do I contribute code to ClickHouse?](/docs/resources/support-center/knowledge-base/general-faqs/how-do-i-contribute-code-to-clickhouse) | How to contribute code to the ClickHouse project. |
| [Why not use something like MapReduce?](/docs/resources/support-center/knowledge-base/general-faqs/mapreduce) | Why MapReduce implementations aren't appropriate for OLAP scenarios. |
| [What does "Не тормозит" mean?](/docs/resources/support-center/knowledge-base/general-faqs/ne-tormozit) | Explainer on what "не тормозит" means. |
| [What is OLAP?](/docs/resources/support-center/knowledge-base/general-faqs/olap) | Explainer on Online Analytical Processing. |
| [What SQL syntax does ClickHouse support?](/docs/resources/support-center/knowledge-base/general-faqs/sql) | Information about ClickHouse SQL syntax support. |
| [Does ClickHouse support real-time updates?](/docs/resources/support-center/knowledge-base/general-faqs/updates) | Information about real-time updates in ClickHouse. |
| [Who is using ClickHouse?](/docs/resources/support-center/knowledge-base/general-faqs/who-is-using-clickhouse) | Learn about who is using ClickHouse. |
| [Why is ClickHouse Keeper recommended over ZooKeeper?](/docs/resources/support-center/knowledge-base/general-faqs/why-recommend-clickhouse-keeper-over-zookeeper) | Why ClickHouse Keeper is recommended over ZooKeeper. |

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