- users-list - monetdb.org

MySQL unix_timestamp() equivalent?
by Vijay Krishna 02 Mar '16

02 Mar '16

Hi, I am looking for an Epoch (bigint) to date/timestamp converter in MonetDB - something similar to unix_timestamp() in MySQL. I referred this page - https://www.monetdb.org/Documentation/SQLreference/Temporal and tried out a few functions, but it seems to work only with the existing Timestamp columns. Am I missing something here? I am using MonetDB Jan2014 release on a Mac OS-X. Any help much appreciated. Thanks & Regards, Vijayakrishna.P. Mobile : (+91) 9500402305.

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MAPI COPY INTO from stream
by Gustavo Brian 02 Mar '16

02 Mar '16

Hi, I'm trying to bulk load data into monetdb through COPY INTO statement on the fly. I've created an aggregator script that will create a session and send chunk of data using MAPI interface. Like this: "sCOPY INTO foo FROM STDIN USING DELIMITERS ',','\\n';" //+ "\n" + "100,10,0,'10'\n" + "\n" I've been following this example: http://dev.monetdb.org/hg/MonetDB/file/tip/java/example/SQLcopyinto.java (haven't tested) I planned to add as part of the monetdb nodejs module: https://github.com/MonetDB/monetdb-nodejs/issues/1 but seems to be out of the scope of that repository. Sadly I'm not getting any error just doesn't work. What's the correct way ? Thanks.

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Typecasting in prepared statements
by Arno Mittelbach 24 Feb '16

24 Feb '16

Hi all, I am having a strange problem regarding prepared queries with Umlaute (e.g., ä). It seems that the rule for type casting strings correspond to the length of the string. The problem is that an Umlaut seems to count for two "normal" characters. Here is an example. Consider the following simple table: create table A (a varchar(4)); Now if we create a prepared statement (ultimately I want to do this from Java) such as prepare select * from A where a = ?; we can execute the statement and supply 4 characters as the argument: exec 3('1234'); This works fine. However, if I am using an Umlaut within the parameter, then things don't work out. For example exec 4('ä123'); fails with the following error message EXEC: wrong type for argument 1 of prepared statement: char, expected varchar However, if I now shorten the parameter by "1" character, it works again. That is, exec 5('ä12'); is ok. Can anybody explain this behavior? Is this a bug? And is there a workaround? The only thing I came up with so far is to double the size of every column. Best regards, Arno

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Slow query - round 2
by Luciano Sasso 24 Feb '16

24 Feb '16

Hi, Do you think that many ( very many ) inserts / updates on this table , inserts that were aborted by network error could corrupt data and cause it? Remember , table have 100M rows. I have table with 30M rows, and run well work. Att, -- Luciano Sasso Vieira Data Scientist & Solutions Architect luciano(a)gsgroup.com.br <http://www.gsgroup.com.br> | tel: 17 3353-0833 | cel: 17 99706-9335 www.gsgroup.com.br <http://www.gsgroup.com.br> --- Este email foi escaneado pelo Avast antivírus. https://www.avast.com/antivirus

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File system level backup of running database
by Dennis Pallett 23 Feb '16

23 Feb '16

Hi all, Is it possible to create a file system level backup of a running MonetDB database? What are the downsides of doing this? For what it's worth, our databases are generally never updated outside of pre-fixed windows so only SELECT queries will be executed during any file system level backup. Best regards, Dennis Pallett

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do these two commands create an error in the dev version of monetdb?
by Anthony Damico 23 Feb '16

23 Feb '16

they do work in the latest release but they crash monetdblite, making me wonder about the root culprit.. thanks all create table my_table (my_id clob, my_double double); SELECT COUNT( DISTINCT my_id ) AS unique_enrollees , QUANTILE( my_double , 0.25 ) AS some_quantile FROM my_table;

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is there a downloadable nightly build exe installer for windows?
by Anthony Damico 23 Feb '16

23 Feb '16

or do i need to do something with these? http://dev.monetdb.org/hg/MonetDB/file/tip/NT/installer64 never done this before..curious how cumbersome it is i want to check whether this is a bug introduced within mserver or a bug specific to monetdblite https://www.monetdb.org/bugzilla/show_bug.cgi?id=3927 thanks!

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Slow query
by Luciano Sasso 21 Feb '16

21 Feb '16

Hi Stefan About "prepare statements calls/traces ", in paralell select count(*), this service that insert in 10 and 10 minutes. But even without such active service , the time is the same, 90 minutes. My mistake, my server have 6 cores. Hi, (as a side note, I'm afraid I'm too "old fashioned" and do no longer understand "modern" MonetDB traces; at least, I have no idea, why there are so many prepare statements calls/traces in your trace of a simple select count(*) query ... ) Having said that, the trace suggests that your machine either has 6 cores, or MonetDB has decided to split it in 6 slices for processing, although you machine has only 4 cores? Also, the trace reveals that the vast majority of the time is spent in 6 (one per slice) sql.tid() calls: ....... -- Luciano Sasso Vieira Data Scientist & Solutions Architect luciano(a)gsgroup.com.br <http://www.gsgroup.com.br> | tel: 17 3353-0833 | cel: 17 99706-9335 www.gsgroup.com.br <http://www.gsgroup.com.br> --- Este email foi escaneado pelo Avast antivírus. https://www.avast.com/antivirus

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Slow query
by Luciano Sasso 21 Feb '16

21 Feb '16

Hi, Martin Yes, before performance analysis, load is zero, the server is Linix console only. My RAM memory is low for this database size. what do you think ? Att, Hi, about slow query Yes, there is, but still left over resources. While the query (which takes 90 minutes) are running, to perform another in another table (9M rows), this latter returns usually in seconds. Hi Its all about concurrent processes while working with MonetDB. All those processes compete for RAM and disk bandwidth. Even running a browser already takes off a few GB from your RAM. At some point, you end up swapping intermediates to disk, which is a slow process (depending on your HDD). For performance analysis, you better shut down all the processes you don't need. Ideally, the CPU load = 0 before doing a performance analysis. > " > > A simple "select count(*) from table", run on 90 minutes. > > that is not normal. most likely there are a lot of other > processes competing for resources. > > > " -- Luciano Sasso Vieira Data Scientist & Solutions Architect luciano(a)gsgroup.com.br <http://www.gsgroup.com.br> | tel: 17 3353-0833 | cel: 17 99706-9335 www.gsgroup.com.br <http://www.gsgroup.com.br> --- Este email foi escaneado pelo Avast antivírus. https://www.avast.com/antivirus

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Slow query
by Luciano Sasso 21 Feb '16

21 Feb '16

Hi, send now trace for query in link: https://drive.google.com/folderview?id=0B0L6U0kZpUaFNUU3ak9PNUFVZW8&usp=sha… Att, -- Luciano Sasso Vieira Data Scientist & Solutions Architect luciano(a)gsgroup.com.br <http://www.gsgroup.com.br> | tel: 17 3353-0833 | cel: 17 99706-9335 www.gsgroup.com.br <http://www.gsgroup.com.br> --- Este email foi escaneado pelo Avast antivírus. https://www.avast.com/antivirus

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