thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-11-25 00:52:02 +00:00
Code Issues Packages Projects Releases Wiki Activity

Delete columnar-database.md

Browse Source
This commit is contained in:
AnaUvarova 2020-12-31 13:55:35 +03:00 committed by GitHub
parent 8b03bef74e
commit 6b5a313dd7
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 0 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
docs/ru/faq/general/columnar-database.md
View File

@ -1,25 +0,0 @@
---
title: What is a columnar database?
toc_hidden: true
toc_priority: 101
---
# Что такое колоночная база данных? {#what-is-a-columnar-database}
A columnar database stores data of each column independently. This allows to read data from disks only for those columns that are used in any given query. The cost is that operations that affect whole rows become proportionally more expensive. The synonym for a columnar database is a column-oriented database management system. ClickHouse is a typical example of such a system.
Key columnar database advantages are:
- Queries that use only a few columns out of many.
- Aggregating queries against large volumes of data.
- Column-wise data compression.
Here is the illustration of the difference between traditional row-oriented systems and columnar databases when building reports:
**Traditional row-oriented**
![Traditional row-oriented](https://clickhouse.tech/docs/en/images/row-oriented.gif#)
**Columnar**
![Columnar](https://clickhouse.tech/docs/en/images/column-oriented.gif#)
A columnar database is a preferred choice for analytical applications because it allows to have many columns in a table just in case, but don’t pay the cost for unused columns on read query execution time. Column-oriented databases are designed for big data processing because and data warehousing, they often natively scale using distributed clusters of low-cost hardware to increase throughput. ClickHouse does it with combination of [distributed](../../engines/table-engines/special/distributed.md) and [replicated](../../engines/table-engines/mergetree-family/replication.md) tables.