Hi, I'm hitting some very strange errors with a few of my data tables. The data users agreement for these datasets does not allow me to share the actual output and I'm having trouble getting a similar error to occur on public data, so hopefully my description of what's going on will help the troubleshooting. I can send more information about the structure of these tables if that would be helpful? This command causes mserver.exe to crash every time: select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr = 64) group by state_cd order by state_cd; This command causes mserver.exe to crash after running it three consecutive times. The first two times, it works. select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr < 65) group by state_cd order by state_cd; ALL of these commands work without any trouble on the same data table: select state_cd from x01 where (bene_age_at_end_ref_yr > 64) group by state_cd order by state_cd; select state_cd , sum( metro ) as metro from x01 group by state_cd order by state_cd; select state_cd , sum( metro ) as metro from x01 where (bene_age_at_end_ref_yr > 64) group by state_cd order by state_cd; select distinct bene_age_at_end_ref_yr from x01 order by bene_age_at_end_ref_yr' ) select state_cd , count(sex) from x01 where (bene_age_at_end_ref_yr = 64) group by state_cd order by state_cd; select state_cd , sum(sex) from x01 group by state_cd order by state_cd; select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr > 64) group by state_cd order by state_cd; select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr >= 64) group by state_cd order by state_cd; I have no idea where to start troubleshooting what's going on here. Can anyone recommend additional tests to diagnose the root of the problem? I really don't understand how flipping the greater than sign on the otherwise same query could cause it to break.. I've pasted a bunch of diagnostics and the mclient in -X mode below, but it really doesn't seem helpful. Thanks!!!!! Here's my mserver.exe version: # MonetDB 5 server v11.15.1 "Feb2013" # Serving database 'medicare_sample', using 4 threads # Compiled for x86_64-pc-winnt/64bit with 64bit OIDs dynamically linked # Found 20.000 GiB available main-memory. # Copyright (c) 1993-July 2008 CWI. # Copyright (c) August 2008-2013 MonetDB B.V., all rights reserved # Visit http://www.monetdb.org/ for further information # Listening for connection requests on mapi:monetdb://127.0.0.1:49800/ # MonetDB/JAQL module loaded # MonetDB/SQL module loaded > When running the first command that breaks inside mclient -X, here's what happens: user(win32):monetdb password: Welcome to mclient, the MonetDB/SQL interactive terminal (Feb2013) mapi_query:128:SELECT "name", "value" FROM sys.env() AS env WHERE "name" IN ('gd k_dbname', 'monet_version', 'monet_release', 'merovingian_uri') fetch next block: start at:4 got next block: length:200 text:&1 0 3 2 3 % .env, .env # table_name % name, value # name % varchar, varchar # type % 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] got complete block: text:&1 0 3 2 3 % .env, .env # table_name % name, value # name % varchar, varchar # type % 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:&1 0 3 2 3 allocating new result set got complete block: text:% .env, .env # table_name % name, value # name % varchar, varchar # type % 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:% .env, .env # table_name got complete block: text:% name, value # name % varchar, varchar # type % 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:% name, value # name got complete block: text:% varchar, varchar # type % 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:% varchar, varchar # type got complete block: text:% 13, 15 # length [ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:% 13, 15 # length got complete block: text:[ "gdk_dbname", "medicare_sample" ] [ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:[ "gdk_dbname", "medicare_sample" ] got complete block: text:[ "monet_version", "11.15.1" ] [ "monet_release", "Feb2013" ] read_line:[ "monet_version", "11.15.1" ] got complete block: text:[ "monet_release", "Feb2013" ] read_line:[ "monet_release", "Feb2013" ] fetch next block: start at:204 got next block: length:0 text: got complete block: text:? read_line:? Database: MonetDB v11.15.1 (Feb2013), 'medicare_sample' closing result set Type \q to quit, \? for a list of available commands auto commit mode: on mapi_query:46:SET TIME ZONE INTERVAL '-05:00' HOUR TO MINUTE fetch next block: start at:206 got next block: length:3 text:&3 got complete block: text:&3 read_line:&3 allocating new result set fetch next block: start at:209 got next block: length:0 text: got complete block: text:? read_line:? closing result set sql>select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr = 64) grou p by state_cd order by state_cd; mapi_query_part:109:select state_cd , sum(sex) from x01 where (bene_age_at_end_r ef_yr = 64) group by state_cd order by state_cd; fetch next block: start at:211 Connection terminated Press any key to continue . . . When running the second command that breaks inside mclient -X, here's what happens: The first two times, the command runs fine.. Then the third time, it gives: read_line:? +----------+-------+ 67 tuples (241.424ms) closing result set sql>select state_cd , sum(sex) from x01 where (bene_age_at_end_ref_yr < 65) grou p by state_cd order by state_cd; mapi_query_part:109:select state_cd , sum(sex) from x01 where (bene_age_at_end_r ef_yr < 65) group by state_cd order by state_cd; fetch next block: start at:2403 Connection terminated Press any key to continue . . .