thevar1able/ClickHouse
1
0
Fork 0
mirror of https://github.com/ClickHouse/ClickHouse.git synced 2024-09-21 01:00:48 +00:00
Code Issues Packages Projects Releases Wiki Activity

update

Browse Source
This commit is contained in:
Anna 2021-03-11 13:06:32 +03:00
parent 7bc6368776
commit be47ad325e
1 changed files with 10 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
docs/en/engines/database-engines/atomic.md
View File

@ -8,26 +8,21 @@ toc_title: Atomic
- What the Database/Table engine does.
- Relations with other engines if they exist.
All tables in DatabaseAtomic have persistent UUID and store data in `/clickhouse_path/store/xxx/xxxyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy/` where `xxxyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy` is UUID of the table.
RENAMEs are performed without changing UUID and moving table data.
Tables in Atomic databases can be accessed by UUID through DatabaseCatalog.
On DROP TABLE no data is removed, DatabaseAtomic just marks table as dropped by moving metadata to /clickhouse_path/metadata_dropped/ and notifies DatabaseCatalog.
Running queries still may use dropped table. Table will be actually removed when it's not in use.
Allows to execute RENAME and DROP without IStorage-level RWLocks
## Creating a Database {#creating-a-database}
``` sql
CREATE DATABASE ...
```
or
## Creating a Table {#creating-a-table}
``` sql
CREATE TABLE ...
```
**Engine Parameters**
**Query Clauses** (for Table engines only)
## Virtual columns {#virtual-columns} (for Table engines only)
List and virtual columns with description, if they exist.
## Data Types Support {#data_types-support} (for Database engines only)
## Data Types Support {#data_types-support}
| EngineName | ClickHouse |
|-----------------------|------------------------------------|
@ -63,4 +58,5 @@ Result:
Follow up with any text to clarify the example.
[Original article](https://clickhouse.tech/docs/en/database_engines/atomic/) <!--hide-->
[Original article](https://clickhouse.tech/docs/en/database-engines/atomic/) <!--hide-->