Brief about Time travel

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;