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4e3038b57f
In commit a664ac7ba5, the Alternator
schema-modifying code (e.g., delete_table()) was reorganized to support
the new Raft-based schema modifications. Schema modifications now work
with an "optimistic locking" approach: We retrieve the current schema
version id ("group0_guard"), reads the current schema and verifies it
can do the changes it wants to do, and then does them with
mm.announce(group0_guard) - which will fail if the schema version is not
current because some other concurrent modification beat us in the race.
This means that we need to do this whole read-modify-write (group0_guard,
checking the schema, creating mutations, calling mm.announce()) in a
*retry loop*. We have such a loop in the CQL code but it's missing in the
Alternator code. In this patch we don't add the loop yet, but add FIXMEs
to remind us where it's missing.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20220214154435.544125-1-nyh@scylladb.com>