February 2018 - users-list

Select from remote table leaves session open
by Николай Чернов 19 Feb '18

19 Feb '18

I have two databases (v11.27.13 both) on two Debian8 machines. One with corrupted table (in my case it got corrupted due to bug in Jul2017-SP1) and another with remote table to the corrupted table. When I run the SELECT query from the remote table I get an error. And the session, opened by this query to the first DB did not close. I see it by querying 'sys.sessions' table. And every time I run this SELECT I get additional record in 'sys.sessions'. This happens only if en error occurs, on successful SELECT the session immediately disappears. How can I force this sessions to close or is it a bug?

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Converting a timestamp to a UNIX timestamp
by Bernát Marcell 15 Feb '18

15 Feb '18

Dear MonetDB users, I'm looking for a way to convert a timestamp (or timestamp string) like "2018-02-14 23:59:59" to a UNIX timestamp using MonetDB's functions. In MySQL this can be done using the function UNIX_TIMESTAMP(), so I'm looking for the MonetDB equivalent of that, if it exists. I found sys.epoch(), but that does the opposite of what I need. Thanks in advance. Best regards, Marcell

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Announcement: New Jul2017-SP4 Bugfix release of MonetDB suite
by Sjoerd Mullender 12 Feb '18

12 Feb '18

The MonetDB team at CWI/MonetDB BV is pleased to announce the Jul2017-SP4 bugfix release of the MonetDB suite of programs. More information about MonetDB can be found on our website at <http://www.monetdb.org/>. For details on this release, please see the release notes at <http://www.monetdb.org/Downloads/ReleaseNotes>. As usual, the download location is <http://dev.monetdb.org/downloads/>. Jul 2017-SP4 bugfix release (11.27.13) Build Environment * Added the .lib and .h files needed for building extensions to the Windows installer. Bug Fixes * 3470: Support setClob without length restrictions * 6468: JDBC 2.27 fails with year < 1000 * 6482: Query failures on order by on union * 6483: Monetdb crashes, on query * 6487: UNION of NULLs with several tables fails * 6488: Semijoin returns duplicate values from a column with unique values * 6489: Sqlitelogictest - Wrong result set of complex conditional query * 6490: Sqlitelogictest - Select query with an IN clause parse error * 6491: SELECT IN returns NULL instead of false when not found * 6492: Persistent hashes stored and then ignored. Storage info not in sync with actual indices. * 6493: Sqlitelogictest - Aggregation query on empty table with DISTINCT clause * 6494: Sqlitelogictest - Algebra operators priority in select query * 6495: Sqlitelogictest - Omitting AS in a result set column alias name * 6496: Sqlitelogictest - Select interval comparisons between floating-points and NULL * 6497: Sqlitelogictest - Select not between query producing wrong results * 6498: large virtual memory spike on BLOB column COUNT * 6499: Crash when trying to replace a function defined in sys from a different schema * 6502: Query with multiple limit clauses does not return anything * 6508: Segmentation fault in mserver5 on Python2 UDF with TIMESTAMP column input that has NULL values (conversion.c:438, PyNullMask_FromBAT) * 6510: Sqlitelogictest: Wrong output in aggregation query * 6512: Monetdb crashes on query with limit after sort with case * 6514: Sqlitelogictest: Range query between NULL values not possible * 6515: Insert null second interval value results in 0 * 6516: Sqlitelogictest unknown bat append operation * 6517: Sqlitelogictest overflow in conversion during MAL plan execution * 6518: Sqlitelogictest: count aggregation with not in operator * 6519: Sqlitelogictest: algebra join between lng and int BATs undefined * 6520: UPDATE with correlated subquery causes assertion (or segfault) * 6522: Sqlitelogictest: IN operator return a single column * 6523: Sqlitelogictest: Case statement subquery missing * 6524: Sqlitelogictest: Crash in aggregation query with IN operator * 6527: Crash using order by alias in subquery

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MonetDB Connection drops issue on concurrency
by Sharma, Sreejith 12 Feb '18

12 Feb '18

Hi All, We have a situation where we are trying to emulate a scenario where we have multiple clients hitting into MonetDB instance in parallel, I mean with concurrency of for say 12 users. Queries are going through fine, however we notice connection drops in some cases and queries get cancelled. We assume, this happens when port is idle and when trying to reconnect there is a SQLConnect failure issues. If it's queries are firing uninterruptedly no issues spotted, if there is any idle situation the issue occurs. Can the "forward" - "redirect" option help here? If not, what other options? Regards, Sreejith

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Diacritic removal
by Roberto Cornacchia 09 Feb '18

09 Feb '18

Just wondering, before I do it myself, whether "normalizing" strings by removing diacritics is a feature that you guys would consider interesting to implement. (I am aware that results of this "normalization" can be unsatisfactory in some cases - I'm ok with most obvious cases covered) Basically, something like what iconv does here: $ echo "Ã é ç" | iconv -f UTF-8 -t ASCII//TRANSLIT A e c I can imagine that these above would be pretty easy to solve using the same hash lookup approach used for case conversion. These, however, are example that produce more than one symbol in output. So that would be a little more complicated. $ echo "æ ß" | iconv -f UTF-8 -t ASCII//TRANSLIT ae ss So I have two questions: 1) Is this something you guys (MonetDB developers) would be interested in implementing? 2) If not - in that case I'll give it a go myself, would you advise an approach similar to the case conversion or to use the iconv lib? Thanks for your input. Rboerto

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Install on Linux with no access to Internet
by ALEX OSSIPOV 08 Feb '18

08 Feb '18

I am trying to install MonetDB with client on the host without access to Internet. Are there any instructions to follow? Thanks Alex

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MonetDB Evaluation - Excessive slowness in a particular query
by Alfio Bettini 06 Feb '18

06 Feb '18

Hi all, we're testing MonetDB performances in order to understand if it could be possible to use it as data mart in our BI software. We're considering a set of queries executed in our test environment (CentOS 7, 32 GB RAM, 4 cpu). All the executed queries have quite good performances (between 10 and 45 seconds) except the following one that is taking several minutes in order to be executed: SELECT id, count(distinct value) FROM table GROUP BY id; The table contains 100 millions of data. It has about 130 columns (varchar, int, bigint, smallint, tinyint, timestamp, datetime). We have no BLOB/CLOB/Text types. The fields used in the query have these data types: id: int value: bigint Can you suggest us any optimizations in order to have this query run faster? Do you know some possible reasons why it's so slow? Kind Regards, Alfio Bettini The information contained in this message, together with any attachments, may be privileged and confidential and is intended for the use of the addressee(s) only. Any review, copying, use or distribution of this email by others (including any of its attachments) is strictly prohibited. If you are not the intended recipient, please destroy this email and its attachments and contact the sender immediately. This email was sent by EidosMedia SpA<http://www.eidosmedia.com>

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SQL Connect issues - ODBC Driver failure when idle situation
by Sharma, Sreejith 06 Feb '18

06 Feb '18

Hi All, Have a quick question - I have a situation where we are trying to emulate a scenario where we have multiple clients hitting into MonetDB instance in parallel, I mean with concurrency of for say 12 users. Queries are going through fine, however we notice some cases when a port/machine is idle and trying to reconnect we are finding SQLConnect failure issues. If it's queries are firing continuously it's fine, here if when some idle situation it may occur. Can the "forward" - redirect option help here? Regards, Sreejith

1 0

SQL Connect issues - ODBC Driver failure when idle situation
by Sharma, Sreejith 01 Feb '18

01 Feb '18

Hi All, Have a quick question - I have a situation where we are trying to emulate a scenario where we have multiple clients hitting into MonetDB instance in parallel, I mean with concurrency of for say 12 users. Queries are going through fine, however we notice some cases when a port/machine is idle and trying to reconnect we are finding SQLConnect failure issues. If it's queries are firing continuously it's fine, here if when some idle situation it may occur. Can the "forward" - redirect option help here? Regards, Sreejith

1 0