When sending your events to a data warehouse via RudderStack, you don't need to define a schema for your event data. RudderStack automatically does that for you by following a predefined warehouse schema.

This guide details the structure of this warehouse schema and the columns created in various tables based on different event types.

Schema

RudderStack uses the source name (written in snake case, for example, source_name) to create a schema in your data warehouse.

The following tables are created in your data warehouse for each RudderStack source connected to it:

NameDescription
<source_name>.identifiesEvery identify call sent from the source is stored in this table, including the properties passed as traits.
<source_name>.usersRudderStack stores all the unique users in this table. Only the latest properties used to identify a user are stored, including the latest anonymousId.
<source_name>.tracksEvery track call sent from the source is stored in this table. It does not include the custom properties present in the event's properties but has some standard properties (listed in the Standard properties section below such as received_at, anonymous_id, context_device_info, etc.
<source_name>.<track_event_name>All the standard properties and the custom properties for a track event are stored in this table. The table name is the event name specified in the track call, e.g., Added to Cart.
<source_name>.pagesEvery page call sent from the source is stored in this table, including the associated event properties.
<source_name>.screensEvery screen call sent from the source is stored in this table, including the associated event properties.
<source_name>.groupsEvery group call sent from the source is stored in this table, including the associated event properties.
<source_name>.aliasesEvery alias call sent from the source is stored in this table, including the associated event properties.

All the event properties are stored as top-level columns in the corresponding table. The nested properties are prefixed with the parent key. For example, an event with properties { product: { name: iPhone, version: 11 }} will result in RudderStack creating the columns product_name and product_version.

Standard RudderStack properties

RudderStack sets the following standard properties on all the above-mentioned tables:

NameDescription
anonymous_idThe user's anonymous ID.
context_<prop>The context properties set in the event.
idThe unique message ID of the event. Not applicable for the users table, as the field be set to the user ID in that case.
sent_atCaptures the time when the event was sent from the client to RudderStack. Conforms to the ISO 8601 date format yyyy-MM-ddTHH:mm:ss.SSSZ.
received_atTimestamp registered by RudderStack when the event was ingested (received). Conforms to the ISO 8601 date format yyyy-MM-ddTHH:mm:ss.SSSZ.
original_timestampTimestamp registered by the RudderStack SDK when the event call was invoked (event was emitted in the SDK).
timestampIf not already specified in the payload, RudderStack calculates this field to account for the client clock skew. The formula used is timestamp = received_at - (sent_at -original_timestamp). Make sure it conforms to the ISO 8601 date format yyyy-MM-ddTHH:mm:ss.SSSZ. For e.g., 2022-02-01T19:14:18.381Z.
event_textThe name of the event mapped from the event key in the track event payload.
eventThe name of the event table in case of the track calls.

RudderStack automatically converts the property names from camel case to snake case. For more information on the properties captured at the API level, refer to the RudderStack Event Specification.

RudderStack reserves the above-mentioned standard properties. In case of any conflict, RudderStack automatically discards the properties set by the user.

Identify

For every identify call, RudderStack creates a record in the identifies table and upserts the records in the users table based on the userId.

In case of Google BigQuery, you can use the views created over the tables to query for unique users in the dataset. Refer to the BigQuery documentation for more details.

A sample identify call is shown below:

rudderanalytics.identify(
"userId",
{
email: "alex@company.com",
first_name: "Alex",
last_name: "Keener",
age: 35,
},
{
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)

The corresponding schemas created for the identifies and users tables are shown in the following sections:

Table: identifies

ColumnTypeExample valueNote
idString4d5a7681-e596-40ea-a81c-bf69f9b297f1Unique messageId generated by RudderStack.
user_idStringuserIdThe userId in the identify call.
anonymous_idString59b703e3-467a-4a1d-9fe6-da27ed319619-
received_atTimestamp2020-04-26 07:00:45.558-
sent_atTimestamp2020-04-26 07:00:45.124-
original_timestampTimestamp2020-04-26 07:00:43.400-
timestampTimestamp2020-04-26 07:00:44.834-
context_ipString0.0.0.0-
context_<prop>String, Intcontext_app_version: 1.2.3, context_screen_density: 2-
emailStringalex@company.com-
first_nameStringAlex-
last_nameStringKeener-
ageInt35-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

Table: users

ColumnTypeValueNote
idStringuserIdThe unique user ID.
received_atTimestamp2020-04-26 07:00:45.558-
context_ipString0.0.0.0-
context_<prop>String, Integercontext_app_version: 1.2.3, context_screen_density: 2-
emailStringalex@company.com-
first_nameStringAlex-
last_nameStringKeener-
ageInt35-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

The users table contains the properties from the latest identify call made for an user. It only has the id column (same as user_id in the identifies table) and does not have the anonymous_id column.

To obtain a user’s anonymous_id, you can query the identifies table by grouping on the user_id column.

Track

For every track call, RudderStack creates a record in both the tracks and <event_name> tables.

A sample track event named Add to Cart is shown below:

rudderanalytics.track(
"Add to Cart", {
price: 5,
currency: "USD",
product_id: "P12345",
product_name: "N95 Mask",
}, {
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)

The corresponding schemas created for the tracks and add_to_cart tables are as shown:

Table: tracks

ColumnTypeExample valueDescription
idString4d5a7681-e596-40ea-a81c-bf69f9b297f1Unique messageId generated by RudderStack.
anonymous_idString59b703e3-467a-4a1d-9fe6-da27ed319619The anonymous ID of the user.
received_atTimestamp2020-04-26 07:00:45.558Timestamp registered by RudderStack when the event was ingested (received).
sent_atTimestamp2020-04-26 07:00:45.124Timestamp set by the SDK when the event was sent from the client to RudderStack.
original_timestampTimestamp2020-04-26 07:00:43.400Timestamp registered by the SDK when the event was invoked (event was emitted in the SDK).
timestampTimestamp2020-04-26 07:00:44.834Calculated by RudderStack to account for the client clock skew. The formula used is: timestamp = received_at - (sent_at - original_timestamp).
context_ipString0.0.0.0-
context_<prop>String, Integercontext_app_version: 1.2.3, context_screen_density: 2-
eventStringadd_to_cartThe name of the corresponding event table.
event_textStringAdd to CartThe name of the event.
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

Table: add_to_cart

ColumnTypeExample valueNote
idString4d5a7681-e596-40ea-a81c-bf69f9b297f1Unique messageIdgenerated by RudderStack.
anonymous_idString59b703e3-467a-4a1d-9fe6-da27ed319619-
received_atTimestamp2020-04-26 07:00:45.558-
sent_atTimestamp2020-04-26 07:00:45.124-
original_timestampTimestamp2020-04-26 07:00:43.400-
timestampTimestamp2020-04-26 07:00:44.834-
context_ipString0.0.0.0-
context_<prop>String, Intcontext_app_version: 1.2.3, context_screen_density: 2-
eventStringadd_to_cartThe name of the event table.
event_textStringAdd to CartThe name of the event.
priceInt5-
currencyStringUSD-
product_idStringP12345-
product_nameStringN95 Mask-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

The event table add_to_cart has the same columns as the tracks table. It also has the properties set by the user via the properties key.

Page/Screen

For every page/screen call, RudderStack creates a record in the corresponding pages or screens table.

A sample page event is shown below:

rudderanalytics.page(
"Cart",
"Cart Viewed",
{
path: "/cart",
title: "Shopping Cart",
url: "https://rudderstack.com",
},
{
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)

The corresponding schema created for the pages/screens table is as shown:

Table: pages/screens

ColumnTypeExample valueNote
idString4d5a7681-e596-40ea-a81c-bf69f9b297f1-
anonymous_idString59b703e3-467a-4a1d-9fe6-da27ed319619-
received_atTimestamp2020-04-26 07:00:45.558-
sent_atTimestamp2020-04-26 07:00:45.124-
original_timestampTimestamp2020-04-26 07:00:43.400-
timestampTimestamp2020-04-26 07:00:44.834-
context_ipString0.0.0.0-
context_<prop>String, Integercontext_app_version: 1.2.3, context_screen_density: 2-
nameStringCart ViewedThe page name.
categoryStringCartThe page category.
pathString/cart-
titleStringShopping Cart-
urlStringhttps://rudderstack.com-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

Group

For every group call, RudderStack creates a record in the corresponding groups table.

A sample group call is shown below:

rudderanalytics.group(
"groupId", {
email: "alex@keener.com",
first_name: "Alex",
last_name: "Keener",
age: 35,
}, {
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)

The corresponding schema created for the groups table is as shown:

Table: groups

ColumnTypeExample valueNote
idString4d5a7681-e596-40ea-a81c-bf69f9b297f1The group ID associated with the current user.
anonymous_idString59b703e3-467a-4a1d-9fe6-da27ed319619-
group_idStringgroupId-
received_atTimestamp2020-04-26 07:00:45.558-
sent_atTimestamp2020-04-26 07:00:45.124-
original_timestampTimestamp2020-04-26 07:00:43.400-
timestampTimestamp2020-04-26 07:00:44.834-
context_ipString0.0.0.0-
context_<prop>String, Integercontext_app_version: 1.2.3, context_screen_density: 2-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

Alias

For every alias/screen call, RudderStack creates a record in the corresponding aliases table.

A sample alias call is shown below:

rudderanalytics.alias("9bb5d4c2", "e6ab2c5e")

Table: aliases

ColumnTypeExample valueNote
user_idString9bb5d4c2The new ID associated with the user.
previous_idStringe6ab2c5eThe previous ID associated with the user.
received_atTimestamp2020-04-26 07:00:45.558-
sent_atTimestamp2020-04-26 07:00:45.124-
original_timestampTimestamp2020-04-26 07:00:43.400-
timestampTimestamp2020-04-26 07:00:44.834-
context_ipString0.0.0.0-
context_<prop>String, Integercontext_app_version: 1.2.3, context_screen_density: 2-
uuid_tsTimestamp2020-04-26 07:31:54:735Added by RudderStack for debugging purposes. Can be ignored for analytics.

Clock skew considerations

RudderStack considers the time at its end to be absolute and assumes any difference on the client-side. Thus, the client clock skew is relative.

If not specified in the payload explicitly, RudderStack calculates timestamp based on originalTimestamp and sentAt to account for the client clock skew.

As mentioned in the above section:

FieldDescription
original_timestampRecords the actual time when the event occurred at the source.
sent_atCaptures the time when the event was sent from the client to RudderStack.
received_atThe timestamp when the event is received(ingested) by the RudderStack server.
timestampCalculated by RudderStack to account for the client clock skew, IF the user does not explicitly specify it in the payload.
sent_at > original_timestamp is always true. However, timestamp can be more or less than the original_timestamp. Refer to the cases below for more details.

Case 1: original_timestamp < received_at

The following table demonstrates an example of original_timestamp < received_at(when the client-side time is less than the time registered by RudderStack):

original_timestampsent_atreceived_attimestamp = received_at - (sent_at - original_timestamp)
2020-04-26 07:00:43.4002020-04-26 07:00:45.1242020-04-26 07:00:45.5582020-04-26 07:00:44.834

In this case, timestamp will be greater than original_timestamp.

Case 2: original_timestamp > received_at

The following table demonstrates an example of original_timestamp > received_at(when the client-side time is more than the time registered by RudderStack):

original_timestampsent_atreceived_attimestamp = received_at - (sent_at - original_timestamp)
2020-04-26 07:00:45.5582020-04-26 07:00:46.1242020-04-26 07:00:43.4002020-04-26 07:00:42.834

In this case, timestamp will be less than original_timestamp.

Accepted timestamp formats

RudderStack recognizes only the following subsets of the ISO 8601 timestamp format:

  • 2019-09-26
  • 2009-05-19 14:39:22
  • 2019-09-26T06:30:12.984Z
  • 2020-02-11 04:56:55.175116
  • 2019-09-26T06:30:12.984+0530
  • 2019-09-26T06:30:12.984+05:30

RudderStack does not recognize any other timestamp format apart from the ones mentioned above.

Reserved keywords

There are some limitations when it comes to using the reserved words in a schema, table, or column names. If these words are used in the event names, traits or properties, RudderStack automatically prefixes an underscore(_) when creating the tables or columns for them in your schema.

Integers are not allowed at the start of the schema or table name. Such schema, column, or table names will be prefixed with an underscore. For e.g., 25dollarpurchase will be changed to _25dollarpurchase.

The following table lists the warehouse-specific documentation references for reserved keywords:

WarehouseReference
Amazon RedshiftLink
Google BigQueryLink
SnowflakeLink

How RudderStack handles data type mismatch

Once RudderStack recognizes and sets a data type for a table column, it will not accept any values for the column that cannot be cast to the specified data type.

The values which cannot be cast are set as NULL in the table and stored in the rudder_discards table.

The rudder_discards table schema is shown below:

ColumnDescription
row_idThe unique identifier (ID) associated with each record in the table. This corresponds to the event's messageId for all the tables except for users table, where it is userId.
table_nameThe table name where the full record is inserted, like tracks, add_to_cart, identifies , etc.
column_nameThe column name corresponding to the property to be added.
column_valueThe discarded column value that caused the data type mismatch.
row_id is the column which users can use to join with original table and update it as required. As mentioned in the above table, it is set to messageId for all tables except the users table, where it corresponds to userId.

The following snippet highlights a sample event whose properties are discarded due to a data type mismatch:

// intial track call using the RudderStack JavaScript SDK
rudderanalytics.track(
"Add to Cart",
{
price: 5, // originally a int value
currency: "USD",
product_id: "P12345",
product_name: "N95 Mask",
added_at: "2020-05-19 14:39:22", // originally a datetime value
},
{
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)
// subsequent track call using the RudderStack JavaScript SDK
rudderanalytics.track(
"Add to Cart",
{
price: "NA", // sent as a string in latest event
currency: "USD",
product_id: 789, // sent as int but can be casted into original string data type
product_name: "N95 Mask",
added_at: "05/25/2020", // sent as invalid datetime value
},
{
context: {
ip: "0.0.0.0",
},
anonymousId: "59b703e3-467a-4a1d-9fe6-da27ed319619",
}
)

The subsequent records created in the rudder_discards table for the discarded properties from the second event shown in the following table:

Row IDTable nameColumn nameColumn value
a21620be-6502-44d6-941d-78209a386d58add_to_cartpriceNA
1e42b2b3-8b6a-49da-8502-83a8db334375add_to_cartadded_at05/25/2020

FAQs

Can I change the namespace (schema name) of my data warehouse in RudderStack?

Yes, you can. Although the default namespace will be the source name, RudderStack gives you the option to explicitly set the namespace while setting up your warehouse destination. For more information, refer to the warehouse-specific destination settings for configuring the namespace in the RudderStack dashboard.

Contact us

For queries on any of the sections covered in this guide, you can contact us or start a conversation in our Slack community.