CREATE SNAPSHOT
¶
Create a new incremental snapshot inside a repository that contains the current state of the given tables and/or partitions and the cluster metadata.
Table of contents
Synopsis¶
CREATE SNAPSHOT repository_name.snapshot_name
{ TABLE table_ident [ PARTITION (partition_column = value [, ...])] [, ...] | ALL }
[ WITH (snapshot_parameter [= value], [, ...]) ]
Description¶
Create a new incremental snapshot inside a repository.
A snapshot is a backup of the current state of the given tables and the cluster
metadata at the point the CREATE SNAPSHOT
query starts executing. Changes
made after that are not considered for the snapshot.
A snapshot is fully qualified by its snapshot_name
and the name of the
repository it should be created in (repository_name
). A snapshot_name
must be unique per repository.
Note
For snapshot names the same restrictions as for table names apply.
This is mainly because snapshot names will likely become stored as file or directory on disc and hence must be valid filenames.
Creating the snapshot operates on primary shards which are not currently relocated. If a shard is being relocated the snapshot of the shard is created when the relocation is completed.
A snapshot only backups the parts of the data that are not yet stored in the given repository by older snapshots, thus creating snapshots is incremental.
Snapshots can include one or more tables, each given as table_ident
. It is
also possible to include only single partitions given the values of the
partition columns.
If ALL
is used, every table in the cluster (except system tables, blob
tables and tables in the information_schema
schema) as well as all
persistent settings and the full cluster metadata is included in the snapshot.
Parameters¶
- repository_name:
The name of the repository to create the snapshot in as ident.
- snapshot_name:
The name of the snapshot as ident.
- table_ident:
The name (optionally schema-qualified) of an existing table that is to be included in the snapshot.
Clauses¶
PARTITION
¶
If the table is partitioned, the optional
PARTITION
clause can be used to create a snapshot from one partition
exclusively.
[ PARTITION ( partition_column = value [ , ... ] ) ]
- partition_column:
One of the column names used for table partitioning
- value:
The respective column value.
All partition columns (specified by the
PARTITIONED BY clause) must be listed inside the
parentheses along with their respective values using the partition_column =
value
syntax (separated by commas).
Because each partition corresponds to a unique set of partition column row values, this clause uniquely identifies a single partition to snapshot.
Tip
The SHOW CREATE TABLE statement will show you the complete list of partition columns specified by the PARTITIONED BY clause.
WITH
¶
[ WITH (snapshot_parameter [= value], [, ...]) ]
The following configuration parameters can be used to modify how the snapshot is created:
- wait_for_completion:
(Default
false
) By default the request returns once the snapshot creation started. If set totrue
the request returns after the whole snapshot was created or an error occurred. The sys.snapshots table can be queried to track the snapshot creation progress ifwait_for_completion
has been set tofalse
.- ignore_unavailable:
(Default
false
) If a given table does not exist the command will fail by default. If set totrue
these tables are ignored and not included in the snapshot.