Ничего не поменял. Теперь каждые 5 секунд то же самое.

2 одинаковых словаря, только парамтер name другой.

2019.02.25 14:58:56.986717 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:58:56.987094 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:01.989168 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:01.989703 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:01.991142 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:01.991632 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:06.993698 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:06.994238 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:06.995768 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:06.996156 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:11.998176 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:11.998693 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:11.999985 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:12.000367 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:17.002434 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:17.002945 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:17.004440 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:17.004831 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:22.007071 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping
2019.02.25 14:59:22.007595 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/?connection_string=DSN%3Dathena_connection&columns=columns%20format%20version%3A%201%0A1%20columns%3A%0A%60Sample%20Block%60%20String%0A&max_block_size=8192
2019.02.25 14:59:22.009144 [ 71 ] {} <Trace> ReadWriteBufferFromHTTP: Sending request to http://localhost:9018/ping

а что в system.dictionaries ? поля lifetime , elements_count, last_exception ?