May 2010 - users-list

[MonetDB-users] updates in a transaction
by Min Lu 19 May '10

19 May '10

Hi, I tried to update a column of a record more than once within a transaction. But it seemed that only the first update took effect. For example, for a table "CREATE TABLE people (id TINYINT PRIMARY KEY, name VARCHAR(128) NOT NULL)", sql>select * from people; +------+-----------------------------+ | id | name | +======+=============+ | 0 | Phil Ivey | | 1 | Michael Jordan | | 2 | Lionel Messi | +------+-----------… [View More]

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[MonetDB-users] crash when doing count(distinct col)
by Sam Mason 18 May '10

18 May '10

Hi, I've just pulled a largish dataset into monetdb (419851473 rows, 8 columns) and it's crashing when I try to do the following: select count(distinct a) from calldata; "a" is an integer column and monetdb gets the right answer of 886693 when I run either: select count(a) from (select a from calldata group by a) x; or select count(a) from (select distinct a from calldata) x; I'm running the latest 64bit .deb packages under ubuntu 10.4. The following is what I get back from mclient: … [View More]

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[MonetDB-users] MonetDB performance
by dariuszs 18 May '10

18 May '10

Hi, So what happens (performance wise) when you have 50GB of memory, 300GB of data and on average 100 concurrent users using all the tables and columns in your database? Thanks. Dariusz.

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[MonetDB-users] MonetDB/SQL: bulk-loading large data sets & adding key constraints
by Stefan Manegold 15 May '10

15 May '10

Dear all, derived from recent experiments and intensive testing, here are some recommendations for bulk-loading large data sets (in particular those larger than your available main memory) in MonetDB/SQL and adding constraints, i.e., primary and foreign keys. First of all, bulk loading should be done from (possibly gzip or bzip2 compressed) CSV files using the SQL `COPY INTO` command; cf., http://monetdb.cwi.nl/SQL/Documentation/Data-Manipulation.html In case your tables come with primary … [View More]

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[MonetDB-users] Help,how to create hash index on table
by 冯亮 15 May '10

15 May '10

Hello, Current I am using MonetDB server v5.18.3 , and as i see in Wiki , MonetDB support hash index ,I intended to create a hash index on a table. But how to do it , i have referred to sqlmanual downloaded from monetdb.cwi.nl, but it simply wrote following format: CREATE [UNIQUE] INDEX <index_name> ON <table_name> ( <column_name>, ...) ; Is that Btree index or hash index or others? Does MonetDB support multiple column hash index? I am looking forward to … [View More]

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[MonetDB-users] Help,how to create hash index on table
by fll 09 May '10

09 May '10

Hello, Current I am using MonetDB server v5.18.3 , and as i see in Wiki , MonetDB support hash index ,I intended to create a hash index on a table. But how to do it , i have referred to sqlmanual downloaded from monetdb.cwi.nl, but it simply wrote following format: CREATE [UNIQUE] INDEX <index_name> ON <table_name> ( <column_name>, ...) ; Is that Btree index or hash index or others? Does MonetDB support multiple column hash index? I am looking forward to … [View More]

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[MonetDB-users] Move of SourceForge bugtracker to MonetDB Bugzilla
by Fabian Groffen 07 May '10

07 May '10

This message is important for all that used to report bugs on our SourceForge tracker, or are planning to report bugs in the future. With the move of our CVS repository to a new Mercurial repository, we have also migrated the bugtracker from SourceForge to a Bugzilla instance. The old SourceForge trackers are no longer in use. Please DO NOT file any bugs there, as they will get lost. We have removed their presence as far as possible to avoid any confusion here. The new location to search, … [View More]

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[MonetDB-users] Parallel Processing
by Nafees Ur Rehman 04 May '10

04 May '10

Hi, Does monetdb has support for parallel processing? If some can guide me on that. Regards Nafees Ur Rehman

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[MonetDB-users] trigger ambiguous issue
by Huabing 03 May '10

03 May '10

I have following trigger statement: CREATE TRIGGER delete_pos_cp AFTER DELETE ON cp referencing old row as o FOR EACH ROW WHEN o.new_id_ IS NOT NULL UPDATE cp SET old_id_ = o.old_id_ WHERE rec_id_ = o.rec_id_; Following error is issued: SELECT: identifier 'rec_id_' ambiguous The last "o.rec_id_" gives rise to this ambigious. Any suggestion on this.

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