FunctionClauseError in anonymous fn/2 in Mariaex.LruCache.take_oldest/1

[marcelotto]

I'm having problems with the execution of a raw sql query on a legacy MySQL db for migration purposes.

SELECT id FROM pictures
WHERE event_id = #{event_id} AND tags REGEXP '[[:<:]]#{tag}[[:>:]]'

First, I couldn't run the query at all, but was getting a handle_close/3 not implemented error. When I noticed some recent changes on Mariaex relating to handle_close, I did upgrade to Mariaex 0.8.0, which fixed this problem.

Although the query can be executed now, it fails after 495 executions during the migration with the following error:

14:54:44.099 [error] GenServer #PID<0.369.0> terminating
** (DBConnection.ConnectionError) client #PID<0.70.0> stopped: ** 
(FunctionClauseError) no function clause matching in anonymous fn/2 in Mariaex.LruCache.take_oldest/1
    lib/mariaex/lru_cache.ex:57: anonymous fn({:__counter__, 198}, {"SELECT id\nFROM pictures\nWHERE ((event_id = 1) AND tags REGEXP '[[:<:]]o[[:>:]]')\n", 2, 1, #Reference<0.0.2.66>, 0}) in Mariaex.LruCache.take_oldest/1
    (stdlib) lists.erl:1263: :lists.foldl/3
    (stdlib) ets.erl:585: :ets.do_foldl/4
    (stdlib) ets.erl:574: :ets.foldl/3
    lib/mariaex/lru_cache.ex:57: Mariaex.LruCache.take_oldest/1
    lib/mariaex/protocol.ex:317: Mariaex.Protocol.prepare_lookup/2
    lib/mariaex/protocol.ex:298: Mariaex.Protocol.handle_prepare/3
    (db_connection) lib/db_connection.ex:957: DBConnection.handle/4

    (db_connection) lib/db_connection/connection.ex:243: DBConnection.Connection.handle_cast/2
    (connection) lib/connection.ex:488: Connection.handle_call/3
    (stdlib) gen_server.erl:615: :gen_server.try_handle_call/4
    (stdlib) gen_server.erl:647: :gen_server.handle_msg/5
    (stdlib) proc_lib.erl:247: :proc_lib.init_p_do_apply/3

The failure doesn't seem to be related to the specific 495th execution of this query, since the same error is raised on another query on the first run of the migration which does some clean up that's omitted after clean up on subsequent migration runs.

[marcelotto]

Your fix solved the problem. Thank you very much.

[liveforeverx]

@marcelotto Thank you for reporting!