Hi All, It seems when i run my SQL in sequence i can repeated break things with a MAL error. If this isn't a bug please can you point me in the right direction but looks like one with me. Master has 4 remote tables and a MERGE table ippacket with all the remote table added. All mserver5 instances are the same version / release. Welcome to mclient, the MonetDB/SQL interactive terminal (Jul2015-SP1) Database: MonetDB v11.21.11 (Jul2015-SP1), 'mapi:monetdb://mdb-master-01:50000/threatmonitor' Type \q to quit, \? for a list of available commands auto commit mode: on sql>\d MERGE TABLE threatmonitor.ippacket REMOTE TABLE threatmonitor.wifi_ippacket REMOTE TABLE threatmonitor.wifi_ippacket2 REMOTE TABLE threatmonitor.wifi_ippacket3 REMOTE TABLE threatmonitor.wifi_ippacket4 sql>select count(*) from ippacket limit 10; +------+ | L1 | +======+ | 951 | +------+ 1 tuple (44.499ms) sql>select guid, recv_date, ip_dst from ippacket limit 10 more>; (mapi:monetdb://monetdb@172.17.0.5/threatmonitor) 'user.l4' undefined in: (rmt3424_X_3_bat_oid_str:bat[:oid,:str],rmt3425_X_6_bat_oid_str:bat[:oid,:str],rmt3427_X_7_bat_oid_str:bat[:oid,:str]) := user.l4(); The second time i run the same query and its absolutely fine. sql>select guid, recv_date, ip_dst from ippacket limit 10 more>; +--------------------------------------+---------------------------+----------------+ | guid | recv_date | ip_dst | +======================================+===========================+================+ | 5f4c9bcb-e4b7-0af1-2919-fdef5623d20a | 2015-07-20 19:52:45 +0000 | 10.130.19.42 | | 2238c353-33cd-5174-31b6-ca57b4decade | 2015-07-20 19:52:45 +0000 | 216.58.209.227 | | 8ac3dde3-92ce-ff27-f6b1-f296b0d139f5 | 2015-07-20 19:52:45 +0000 | 10.130.19.42 | | 7a204771-8623-e498-5f45-ba1c58adb3da | 2015-07-20 19:52:45 +0000 | 85.25.200.151 | | 496ab33b-3ae9-56b5-9108-209413dcddeb | 2015-07-20 19:52:45 +0000 | 85.25.200.151 | | a1537072-8545-74eb-3b7e-9615a4c534ac | 2015-07-20 19:52:45 +0000 | 10.130.19.42 | | 91124c5a-0854-7f21-e60a-f175e45d68d1 | 2015-07-20 19:52:45 +0000 | 10.130.19.42 | | acefc01b-6ef8-6197-f5c0-27194e5749db | 2015-07-20 19:52:45 +0000 | 85.25.200.151 | | f0694ee8-2e7f-e019-a96e-450489ae8f37 | 2015-07-20 19:52:45 +0000 | 10.130.19.42 | | 78c246a9-eba2-79b5-fb87-59609f44a7d9 | 2015-07-20 19:52:45 +0000 | 85.25.200.151 | +--------------------------------------+---------------------------+----------------+ 10 tuples (63.443ms) sql> I've attached my example schema. Regards, Brian Hood