I added this information as a comment to bug *2825243* but I'm not sure if it's the same so I thought I'd post it here also to see about getting some feedback: I am experiencing widespread data corruption when restarting the May2009-SP1 MonetDB release also, but mine is much simpler. On 64-bit ubuntu: Linux dsvm01 2.6.24-23-server #1 SMP Wed Apr 1 22:14:30 UTC 2009 x86_64 GNU/Linux With a table defined as follows: CREATE TABLE "tablespace"."test_table" ( "col1" varchar(50), "col2" varchar(50), "col3" varchar(50), "col4" varchar(50), "col5" varchar(50), "col6" int, "col7" timestamp(7), "col8" int, "col9" int, "col10" int ); I imported 20998687 records into this table with all columns populated and ran a couple of queries to check the data: select count(*) from test_table ; [ 20998687 ] select count(*) from test_table where col1 = '' or col2 = '' or col3 = ''; [ 0 ] select max(col7), min(col7) from test_table ; [ 2009-07-25 14:17:15.538000, 2009-07-24 15:29:12.524000 ] During the time I loaded the data and ran these queries I did not restart the database, it had been up for about 3 days I then issued: monetdb stop db and monetdb start db and re-ran the queries: select count(*) from raw_plays ; [ 20998687 ] select count(*) from raw_plays where col1 = '' or col2 = '' or col3 = ''; [ 20852061 ] select max(col7), min(col7) from test_table ; [ 2009-07-25 14:17:15.538000, -1-01-01 00:00:00.000000 ] This is some serious data corruption, I've lost data in the vast majority of these records! 73, Matthew W. Jones (KI4ZIB) http://matburt.net