February 2013 - users-list

TPCH Throughput/latency for MonetDB
by Hassan, Ahmad 12 Feb '13

12 Feb '13

Hi, I intend to run TPCH benchmark on MonetDB. I have executed one iteration of benchmark through run.all script provided under sql/benchmarks/tpch. Please may I know if there is a script or framework available to run tpch benchmark for 'X' duration and get throughput and latency numbers for each query? Second, I want to generated data with big scale factor. I searched monetdb mailing list and found out that DBGEN should be used for that. As there is no specific DBGEN provided by monetdb so I … [View More]

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monetdb status health
by Tapomay Dey 12 Feb '13

12 Feb '13

My questions are simple: what causes crashes? what is health? how do we stop health from degrading? Following is the status of my db- msearch_stats_db: database name: msearch_stats_db state: running locked: no scenarios: mal sql msql start count: 140 stop count: 1 crash count: 138 current uptime: 1m 49s average uptime: 15m 33s maximum uptime: 15m 33s minimum uptime: 15m 33s last start with crash: 2013-02-… [View More]

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Suggested correction for the Java SQLcopyinto example
by Percy Wegmann 09 Feb '13

09 Feb '13

Dear Monet team, I've been getting quite a bit of use out of your example code here: http://dev.monetdb.org/hg/MonetDB/file/tip/java/example/SQLcopyinto.java Recently, though, I ran into a problem. If the "COPY INTO" statement that I issue is wrong, for example the referenced table doesn't exist, Monet comes back with an error. The example isn't checking for this error condition and proceeds to send data anyway. With a really large batch of data, this becomes a problem because the SQL … [View More]

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Requirement gathering and questions about binary bulk loading.
by Brandon Jackson 08 Feb '13

08 Feb '13

Hello fellow MonetDB'ers, The Pentaho MonetDB Bulk Loader transformation step is now working pretty well in our tests. http://ci.pentaho.com/view/Data%20Integration/job/Kettle contains a continuous integration build of the software if anyone wanted to play with it. New Transformation -> Steps -> Bulk Loading (category)-> MonetDB Bulk Loader Thank you for the previous information about enabling log output from the MonetDB JDBC driver. After killing a stalled "monetdb start ~/sg-farm" … [View More]thread and restarting it, MonetDB decided to work really well. It was suggested early on that I take a look at the binary bulk loading approach to get the fastest results. Now that I have a streaming ascii version of a bulk loader done for Pentaho Data Integration, I wanted to come back to the binary approach and see what that might look like and what to be aware of. I read http://www.monetdb.org/Documentation/Cookbooks/SQLrecipies/BinaryBulkLoad It looks like the requirements are: 1. Write a physical file per column to the disk the monetdb farm exists on. 2. Tables with DATES, TIMESTAMPS or UTF-8 characters ie: Simplified Chinese are verboten and must be handled with COPY INTO .... USING DELIMITERS Assuming the above is a correct understanding, given the command below: copy into Tmp from ('path_to_file_i', 'path_to_file_f', 'path_to_file_s'); 1. If run from a computer separate from the machine running the monetdb server, would the 'path_to_file_i' be a pathname relative to the monetdb farm root directory on the remote server machine? 2. This process should work for appending new data on to an existing table, right? 3. Am I out of luck if my table has any of the verboten data types mentioned above mixed in with supported binary bulkloadable types; aka C-array style data types? 4. If not out of luck for a mixed type table, what is the procedure to load the table? In practice I imagine I will not need to fret too much about DATES needing a COPY INTO .... USING DELIMITERS ascii streaming approach because it is likely part of a dimension table with integer keys matching integers on a fact table, which is far more likely to have the supported types MonetDB Binary Bulk-loading likes. Is it true that MonetDB does not handle joins well, but instead prefers single, denormalized tables with many columns? >From what you know of the internals of MonetDb, is the effort to make some kind of streaming binary bulk loader worth it in terms of execution time on the database converting to native binary types? The documentation used the words, 'slightly faster', but I do not have a feel for when 'slightly' makes a big difference. Thanks again for considering these questions. Brandon [View Less]

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High memory usage while loading data with many columns
by Andrew Duffey 08 Feb '13

08 Feb '13

Hi, I'm loading data into a table with >20,000 columns and several hundred thousand rows using "COPY INTO". It works, but I can't seem to make it take less than about 30GB of memory. I've tried specifying the number of records as well. Is there any way to reduce memory usage when loading? Is this much memory usage expected? It's a shame because our queries take very little memory. We have to size our machine simply to handle the load. It's impressive (and very convenient) that I can … [View More]

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Data storage capacity in monetdb
by KHALED DEHDOUH 06 Feb '13

06 Feb '13

I installed the version of windows for monetdb http://www.monetdb.org/Downloads. I installed a database column, but when I went over 30 GB of stokage given. the query response time has become very slow. Please, I have two questions: - Are this version is limited or no storage ? - I have noticed that the name of the database is by default "demo". Can i create another one with this version with 1 TB?

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Create stored procedure to add a list of ID's to a table
by Richard Siebeling 05 Feb '13

05 Feb '13

Hello, is it possible to create a stored procedure in MonetDB that will have one parameter containing a string with several thousands of comma-separated ID's and insert these comma-separated ID's as separate rows into a table? I am receiving thousands of ID's from a separate webservice and want to join these ID's to a table in monetDB, aggregate the results and return them back to the client for further processing in the GUI. I tried inserting the ID's into a temporary table using insert … [View More]

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Memory allocations in MonetDB
by Hassan, Ahmad 04 Feb '13

04 Feb '13

Hi Team, I am running monetdb with default settings. After profiling the application instructions, I have noticed that all the memory allocation are currently being performed by the following functions: GDKmalloc, GDKmallocmax, GDKzalloc, HEAPalloc So mmap and malloc are being used with in all GDK* and HEAPalloc. I have three questions please: 1) Which memory allocations of monetdb are performed through mmap and which memory allocation are performed through malloc. I know this is very open … [View More]

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