Metadata Column __hevo_id

What is __hevo_id?

__hevo_id is added to Events in some Sources which do not provide any Primary Key by default.

In Sources that generate mutable data, a primary key is required to perform updates in the Destination. You can read more about it here.

For Sources that generate immutable data, a Primary key is required to ensure exactly-once delivery semantics. Hevo’s architecture guarantees at-least-once delivery semantics by default. But, by having Primary keys in the Events, Hevo is able to achieve exactly-once delivery semantics. However, if a few duplicates do not affect you a lot, or if you have any other processes to remove duplicates from the Events later, you can choose to not create primary keys in the Destination tables while creating mappings.

How is __hevo_id generated?

Source	__hevo_id generated from	Examples
Appsflyer	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
CleverTap	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
Facebook Ads	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
FlatFiles (Google Sheets, CSV files from S3 or FTP/SFTP)	fileName_rowNumber	Sheet’s filename_rowNumber of each record. (filename_1)
Google Ad Words	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
Google Analytics	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
Kafka	timestamp-hevo_consumer_id-local_increamenting_id	Timestamp - Event payload ingested time. Hevo Consumer ID - Hevo Consumer’s Unique ID. Local Incrementing ID - An incrementing id local to each consumer. (1567422223363-278-16)
Mixpanel	The hash of each Event-payload	SHA256-Hash values of each payload that have been ingested.
REST API	timestamp-hevo_consumer_id-local_increamenting_id	Timestamp - Event payload ingested time. Hevo Consumer ID - Hevo Consumer’s Unique ID. Local Incrementing ID - An incrementing id local to each consumer. (1567422223363-278-16)
Webhooks	timestamp-hevo_consumer_id-local_increamenting_id	Timestamp - Event payload ingested time. Hevo Consumer ID - Hevo Consumer’s Unique ID. Local Incrementing ID - An incrementing id local to each consumer. (1567422223363-278-16)