hashserv: Fix diverging report race condition

Fixes the hashequivalence server to resolve the diverging report race
error. This error occurs when the same task(hash) is run simultaneous on
two different builders, and then the results are reported back but the
hashes diverge (e.g. have different outhashes), and one outhash is
equivalent to a hash and another is not. If taskhash was not originally
in the database, the client will fallback to using the taskhash as the
suggested unihash and the server will see reports come in like:

    taskhash: A
    unihash: A
    outhash: B

    taskhash: C
    unihash: C
    outhash: B

    taskhash: C
    unihash: C
    outhash: D

Note that the second and third reports are the same taskhash, with
diverging outhashes.

Taskhash C should be equivalent to taskhash (and unihash) A because they
share an outhash B, but the server would not do this when tasks were
reported in the order shown.

It became clear while trying to fix this that single large table to
store all reported hashes was going to make these updates difficult
since updating the unihash of all entries would be complex and time
consuming. Instead, it makes more sense to split apart the database into
two tables: One that maps taskhashes to unihashes and one that maps
outhashes to taskhashes. This should hopefully improve the parsing query
times as well since they only care about the taskhashes to unihashes
table, at the cost of more complex INNER JOIN queries on the lesser used
API.

Note this change does delete existing hash equivlance data and starts a
new database table rather than converting existing data.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/hashserv/client.py b/lib/hashserv/client.py
index 8cfd90d6a..b2aa1026a 100644
--- a/lib/hashserv/client.py
+++ b/lib/hashserv/client.py
@@ -111,6 +111,7 @@ class Client(bb.asyncrpc.Client):
             "report_unihash",
             "report_unihash_equiv",
             "get_taskhash",
+            "get_outhash",
             "get_stats",
             "reset_stats",
             "backfill_wait",