Hi, Matthew,

How are you importing your data? Copy or insert?

Because we had such issue before, but in our case, it’s extreme, it lost all the data we inserted when we restart the database.

The way to get around this is by setting our database into a single user mode, in the monetdb5.conf, add a line gdk_single_user=yes.

We managed keep the data in this way, so maybe you can give it a try.

Best Regards

Allen

---

From: Matthew Jones [mailto:mat@matburt.net]
Sent: Monday, July 27, 2009 7:28 AM
To: monetdb-users@lists.sourceforge.net
Subject: [MonetDB-users] massive data loss on stop, start

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