PENDING_COMMIT_TIMESTAMP() in SELECT supported in emulator, unsupported in Cloud Spanner

[jzelinskie]

We're creating rows in one table and copying them in to another table for auditing within the same transaction. We initially tried to copy using a subquery along the lines of INSERT ... FROM (SELECT PENDING_COMMIT_TIMESTAMP(), columns... FROM table).

Cloud Spanner does not support PENDING_COMMIT_TIMESTAMP() in a SELECT statement, but the emulator did not throw any errors when provided a query as described above. It was only once we ran against a live Cloud Spanner instance that we discovered this type of query was unsupported.

[jameslintaylor]

My team is running into a similar issue. Specifically that PENDING_COMMIT_TIMESTAMP is allowed by the emulator in a COALESCE, in odds with:

The PENDING_COMMIT_TIMESTAMP function may only be used as a value for INSERT or UPDATE of an appropriately typed column. It cannot be used in SELECT, or as the input to any other scalar expression.

From https://cloud.google.com/spanner/docs/reference/standard-sql/timestamp_functions

[xinjiacs]

V15.5 is out, we believe that issue has been resolved, and emulator should have the same behavior with cloud spanner. Thanks for reporting this issue.

[gauravpurohit06]

Thank you @jzelinskie for reporting the issue. Closing it.