spanner: InvalidArgument: 400 Previously received a different request with this seqno. seqno=4 with no concurrency applied about python-spanner

[larkee]

I have managed to run into this same error without concurrency:

from google.cloud import spanner

client = spanner.Client()
instance = client.instance(INSTANCE)
database = instance.database(DATABASE)

sess = database.session()
sess.create()

txn = sess.transaction()

txn.begin()
try:
    txn.execute_update(
        "INSERT Singers (SingerId, FirstName, LastName) VALUES "
        "(10, 'Taylor', 'Swift'),"
    )
except Exception as e:
    print("error:")
    print(e)

txn.execute_update(
    "INSERT Singers (SingerId, FirstName, LastName) VALUES "
    "(10, 'Taylor', 'Swift')"
)

txn.commit()

The output is:

error:
400 Syntax error: Expected \"(\" but got end of statement [at 1:79]\nINSERT Singers (SingerId, FirstName, LastName) VALUES (10, \'Taylor\', \'Swift\'),\n   

and raises:

google.api_core.exceptions.InvalidArgument: 400 Previously received a different request with this seqno. seqno=0

The problem seems to arise when a execute_sql, execute_batch_dml, or execute_streaming_sql call made by a Transaction or Snapshot raises an exception as it fails to increment _execute_sql_count. I am looking into a possible fix.

Thanks for finding this!

[odeke-em]

@skuruppu @larkee I am getting this error quite a lot with the spanner-django project as per https://travis-ci.com/orijtech/spanner-orm/jobs/283644877#L611 which you have access to with your Github accounts.