Hi Stefan:

We have seen this problem with Nov-2010 release way back. In addition to the deleted records showing up, we also saw significant degradation in query performance after data updates. I think I recently saw an email from another user (Vladimir Vlach) who reported the same issue with performance degradation with updates. But, I am not sure if these issues still exist in the post Nov-2010 releases because we developed elaborate work-arounds to rebuild the db with new data instead of updating or deleting records from MonetDB.

Sorry that I don't have more details for you.... I do have a vague recollection from a conversation that I had with my staff that there might be a bug with the auto commit.

Osmin, can you let us know what version of MonetDB that you are using and whether you are using mclient and whether you have tried the deletes without auto-commit?

Henry



On Wed, May 4, 2011 at 1:03 PM, <Stefan.Manegold@cwi.nl> wrote:
Hi,

seems to work fine for me:

========
sql>create table t (a int);
operation successful
sql>insert into t values (1);
1 affected row (96.067ms)
sql>insert into t values (2);
1 affected row (22.964ms)
sql>insert into t values (3);
1 affected row (22.058ms)
sql>select * from t;
+------+
| a    |
+======+
|    1 |
|    2 |
|    3 |
+------+
3 tuples (1.854ms)
sql>select count(*) from t;
+------+
| L15  |
+======+
|    3 |
+------+
1 tuple (1.853ms)
sql>delete from t where a=2;
1 affected row (21.234ms)
sql>select * from t;
+------+
| a    |
+======+
|    1 |
|    3 |
+------+
2 tuples (2.044ms)
sql>select count(*) from t;
+------+
| L16  |
+======+
|    2 |
+------+
1 tuple (1.979ms)
========

In case you find the problem (easily?) reproducable, please file a detailed
bug report via
http://bugs.monetdb.org/


Stefan


On Wed, May 04, 2011 at 12:56:35PM -0600, Osmin Castillo wrote:
> Anyone?
>
> 2011/4/28 Osmin Castillo <osmin.castillo@gmail.com>
>
> > Hi guys:
> >
> > After delete some records from a table using a "delete from table where
> > field=value" criteria, why the "select cont(0) from table" still shows the
> > same records count? Maybe the records are only "marked" and not really
> > removed from the table? Thanks in advance
> >
> > Osmin

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| http://CWI.nl/~manegold/ | Science Park 123 (L321) |
| Tel.: +31 (0)20 592-4212 | 1098 XG Amsterdam  (NL) |

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