Snowflake provides time travel capabilities that allow querying, cloning, and restoring data from the past. Data is retained for a configurable time period before being moved to a fail-safe storage. Time travel SQL extensions like the AT/BEFORE clauses allow pinpointing historical data by timestamp, offset, or statement ID. Dropped tables, schemas, and databases can be listed, and restored using commands like UNDROP within the retention period.

1. 1
Snowflake Time Travel
 Using Time Travel, following actions within a defined period of time can
be performed:
 Query data in the past that has since been updated or deleted
 Create clones of entire tables, schemas, and databases at or before specific
points in the past
 Restore tables, schemas, and databases that have been dropped
 Once the defined period of time has elapsed, the data is moved
into Snowflake Fail-safe and these above actions can no longer be
performed

2. 2
Snowflake Time Travel

3. 3
Snowflake Tables
Type Persistence Cloning (source type =>
target type)
Time Travel Retention P
eriod (Days)
Fail-safe Period (Days)
Temporary Remainder of session Temporary =>
Temporary Temporary
=> Transient
0 or 1 (default is 1) 0
Transient Until explicitly dropped Transient =>
Temporary Transient =>
Transient
0 or 1 (default is 1) 0
Permanent (Standard
Edition)
Until explicitly dropped Permanent =>
Temporary Permanent
=> Transient Permanent
=> Permanent
0 or 1 (default is 1) 7
Permanent (Enterprise
Edition and higher)
Until explicitly dropped Permanent =>
Temporary Permanent
=> Transient Permanent
=> Permanent
0 to 90 (default is
configurable)
7

4. Snowflake Time Travel
4
Time Travel SQL Extensions
 AT | BEFORE clause which can be specified in SELECT statements and
CREATE…CLONE commands
 The clause uses one of the following parameters to pinpoint the exact
historical data you wish to access:
 TIMESTAMP
 OFFSET (time difference in seconds from the present time)
 STATEMENT (identifier for statement, e.g. query ID)
 UNDROP command for tables, schemas, and databases

5. 5
Snowflake Time Travel (optional )
For example: create a clone of a table
 Following CREATE TABLE command creates a clone of a table as of the date
and time represented by the specified timestamp:
create table restored_table clone my_table at(timestamp => 'Sat, 09 May 2015
01:01:00 +0300'::timestamp_tz);
 Following CREATE SCHEMA command creates a clone of a schema and all
its objects as they existed 1 hour before the current time:
create schema restored_schema clone my_schema at(offset => -3600);
 Following CREATE DATABASE command creates a clone of a database and all
its objects as they existed prior to the completion of the specified statement:
create database restored_db clone my_db before(statement => '8e5d0ca9-005e-

6. 6
Snowflake Time Travel
Dropping and Restoring Objects
Following commands are used to Drop a Table, Schema, or Database :
DROP TABLE
DROP SCHEMA
DROP DATABASE

7. 7
Snowflake Time Travel
show tables history like 'load%' in db_name.schema_name;
show schemas history in db_name);
show databases history;
Dropped tables, schemas, and databases can be listed using the following commands
with the HISTORY keyword specified:
SHOW TABLES
SHOW SCHEMAS
SHOW DATABASES
Listing Dropped Objects
Examples

8. 8
Snowflake Time Travel
A dropped object that has not been purged from the system can be restored using the
following commands:
UNDROP TABLE
UNDROP SCHEMA
UNDROP DATABASE
Restoring Objects
For example:
undrop table table_name;
undrop schema schema_name;
undrop database database_name;