On 09/11/2013 06:37 AM, Steven Hardy wrote:
I'm investigating some issues, where data stored to a text column in mysql
is silently truncated if it's too big.
It appears that the default configuration of mysql, and the sessions
established via sqlalchemy is to simply warn on truncation rather than
raise an error.
This seems to me to be almost never what you want, since on retrieval the
data is corrupt and bad/unexpected stuff is likely.
This AFAICT is a mysql specific issue[1], which can be resolved by setting
sql_mode to "traditional"[2,3], after which an error is raised on truncation,
allowing us to catch the error before the data is stored.
My question is, how do other projects, or oslo.db, handle this atm?
It seems we either have to make sure the DB enforces the schema/model, or
validate every single value before attempting to store, which seems like an
unreasonable burden given that the schema changes pretty regularly.
Can any mysql, sqlalchemy and oslo.db experts pitch in with opinions on
this?
Nova has a PostgreSQL devstack gate, which occasionally catches errors
that MySQL lets through. For example,
https://bugs.launchpad.net/nova/+bug/1217167
Unfortunately we have some MySQL-only code, and PostgreSQL obviously
can't catch such errors there.
I think we should consider turning off auto-truncation for MySQL on our
CI boxes.
--
David Ripton Red Hat drip...@redhat.com
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