Metadata Column __hevo_id
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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. Read Handling of Updates for more information.
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 has been ingested. |
| CleverTap | The hash of each Event-payload | SHA256-Hash values of each payload that has been ingested. |
| Facebook Ads | The hash of each Event-payload | SHA256-Hash values of each payload that has been ingested. |
| FlatFiles (Google Sheets, CSV files from S3 or FTP/SFTP) | rowNumber | The row number of each record in the file. (Example, 231) |
| Google Ad Words | The hash of each Event-payload | SHA256-Hash values of each payload that has been ingested. |
| Google Analytics | The hash of each Event-payload | SHA256-Hash values of each payload that Hash been ingested. |
| Kafka | timestamp-hevo_consumer_id-local_incrementing_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 has been ingested. |
| MongoDB | The hash of the data type of the _id field and its value. |
Suppose the _id value is numeric 1. Then, __hevo_id is the SHA256 hash of “Integer-1”. |
| 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) |
| Taboola | The hash of all the primary keys | SHA256-Hash values of all the primary keys. |
| 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) |
Revision History
Refer to the following table for the list of key updates made to this page:
| Date | Release | Description of Change |
|---|---|---|
| Jun-28-2021 | NA | Updated the hevo_id generation information for flat files (Google Sheets, CSV files from S3 or FTP/SFTP). |
| Jun-28-2021 | 1.61 | Added a row for __hevo_id determination for MongoDB. |