- users-list - monetdb.org

Announcement: New Dec2016-SP4 Bugfix release of MonetDB suite
by Sjoerd Mullender 01 May '17

01 May '17

The MonetDB team at CWI/MonetDB BV is pleased to announce the Dec2016-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/>. Dec 2016-SP4 bugfix release MonetDB5 Server * Fixed a bug causing a crash during cleanup when mserver5 is stopped with monetdb stop database. * Some memory leaks were plugged. MonetDB Common * A potential deadlock was fixed in order index creation. * A bug that could happen during recovery of the write-ahead log (WAL) was fixed. See changeset 98ad79c555cc for details. SQL * Some memory leaks were plugged. * Upgrade code was added for an old change in the sys.settimeout function. * A bug was fixed with the automatic "vacuum" operation on system tables. Bug Fixes * 6110: cast of a SQL boolean value to a string or clob or (var)char is wrong * 6254: Crash (and assertion failure) after querying a view which uses a correlated subquery in the select-list * 6256: Assertion Trigger on FULL OUTER JOIN with more than two BETWEEN clauses * 6257: wrong count values (1 instead of 0) for correlated aggregation queries * 6258: Vulnerability in FITS and NETCDF data vaults * 6259: crash on select query from sqlitelogictests * 6260: Sqlitelogictest crash * 6288: Function cannot find column in merge table * 6295: msqldump writes unescaped timestamp values when using inserts

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Excution Model of MonetDB (column-at-a-time...or?)
by Mahmoud Mohsen 15 Apr '17

15 Apr '17

Greetings Eyal, /Thank you/ a lot for your quick /response/, >Are you interested in that for purposes of academic research? Yes, If you could suggest me similar work, that is opensource, I would very much appreciate it. Best Regards, Mahmoud Mohsen >1. Column-at-a-time. >2. I'm almost certain the answer is "No", but even if it had been "Yes", >the changes in MonetDB since then would make it unrealistic to use it >with today's code without rewriting a lot of it if not all of it. And >the changes since those days in the closed-source Vectorwise/Actian >Vector have also been significant >Are you interested in that for purposes of academic research? >Eyal On 04/14/2017 07:39 PM, Mahmoud Mohsen wrote: >/Greetings, />//>/The current query engine of the MonetDB...what model of processing does />/it follow....(column-at-a-time, tuple-at-a-time, vector-at-a-time)? />//>/one last question.... />//>/Has the X100 query engine ever been published as opensource in the older />/releases of MonetDB? />//>/Thanks a lot in advance, />//>/Best Regards, />//>/Mahmoud Mohsen /

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Excution Model of MonetDB (column-at-a-time...or?)
by Mahmoud Mohsen 14 Apr '17

14 Apr '17

Greetings, The current query engine of the MonetDB...what model of processing does it follow....(column-at-a-time, tuple-at-a-time, vector-at-a-time)? one last question.... Has the X100 query engine ever been published as opensource in the older releases of MonetDB? Thanks a lot in advance, Best Regards, Mahmoud Mohsen

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remote tables and OCC
by Roberto Cornacchia 12 Apr '17

12 Apr '17

I'm curious to know whether optimistic concurrency control applies across remote tables. For example: db1 contains tableA db2 defines remote tableA-> db1 say that db1 modifies tableA, while db2 already had an open transaction on the same table. Will the transaction on db2 fail? Roberto

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COLcopy
by Roberto Cornacchia 04 Apr '17

04 Apr '17

I'm seeing a strange behaviour with COLcopy(). (Dec2016, optimized, non-devel compilation) In short, it seems to take almost half second to copy a 1-tuple string (view) bat. Inspected with gdb, I see that the copy falls in "(3) we can copy the heaps (memcopy, or even VM page sharing)", with the following values: cnt = 1 bunstocopy = BUN_NONE isVIEW(b) = TRUE VIEWtparent(b) = 0 b->T.heap.size = 1024 b->T.vheap.size = 1094320128 The actual tail and heap copy then takes place: heapcopy(bn, "tail", &bthp, &b->theap) heapcopy(bn, "theap", &thp, b->tvheap) Does this mean that a heap of almost 1GB has been copied for a 1-tuple view? Roberto

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Wrong n. of rows in MAL plan?
by Roberto Cornacchia 04 Apr '17

04 Apr '17

Could you give me a feedback on whether this is a possible bug or not? In the following excerpt: X_377=<tmp_2516>[9]:bat[:str] := mat.packIncrement(X_376=<tmp_2516>[9]:bat[:str],X_335=<tmp_20775>[0]:bat[:str]);"] ... ... X_100=<tmp_2516>[10]:bat[:str] := mat.packIncrement(X_377=<tmp_2516>[10]:bat[:str],X_336=<tmp_24175>[1]:bat[:str]);"] X_377 has 9 rows. But when it's used as a parameter for X_100, it is reported to have 10 rows. In between the two instructions above, X_377 is never used. Roberto

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Announcement: New Dec2016-SP3 Bugfix release of MonetDB suite
by Sjoerd Mullender 31 Mar '17

31 Mar '17

The MonetDB team at CWI/MonetDB BV is pleased to announce the Dec2016-SP3 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/>. Dec 2016-SP3 bugfix release MonetDB Common * Fixed a bug when appending string bats that are fully duplicate eliminated. It could happend that the to-be-appended bat had an empty string at an offset and at that same offset in the to-be-appended-to bat there happened to be a (sequence of) NULL(s). Then this offset would be used, even though it might nog be the right offset for the empty string in the to-be-appended-to bat. This would result in multiple offsets for the empty string, breaking the promise of being duplicate eliminated. Bug Fixes * 6138: Weak duplicate elimination in string heaps > 64KB * 6183: ResultSet returns double quoted column name if name contains space characters * 6216: Assertion raised (sqlsmith) * 6219: Crash in rel_optimizer (sqlsmith) * 6227: Monetdb fails on remote tables * 6228: mclient crashes if real column is multiplied by it itself * 6229: ANALYZE, unexpected end of input * 6230: ANALYZE, syntax error * 6237: semijoin with empty right bat does not return immediately * 6242: Crash on rel_reduce_groupby_exps (sqlsmith) * 6243: Static optimization gives wrong result (1 + NULL = -127) * 6245: Nested query crashes all versions of MonetDB or gives wrong result starting from Dec2016-SP2 * 6246: update statements: references to a table do not bind to its alias * 6247: Type analysis issue (sqlsmith) * 6248: update statements: the semantic stage does not resolve the relation in the from clause * 6250: Assertion failure when querying a Blob column with order by DESC * 6251: Crash after adding an ordered index on sys.statistics column and querying sys.statistics * 6253: FITS Data Vaults does not work when using user/pw and other than sys schema name

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Remote Table IS NULL
by Siklós Gábor 27 Mar '17

27 Mar '17

Hi there, We have an issue about the remote table on monetdb version of 2016 (sp1 and sp2) on Ubuntu 14.04 and on Windows Server2012 R2 The scenario for reproducing the issue with two nodes on node1 Create a table on remote node and fill it: CREATE TABLE test(id int not null, name text, valid boolean); INSERT INTO test (id, name) VALUES (1, '1'); INSERT INTO test (id, name) VALUES (2, '2'); INSERT INTO test (id) VALUES (3); on node2 CREATE REMOTE TABLE test(id int not null, name text, valid boolean) ON 'mapi:monetdb://node1:50000/dbfarm'; Then on node2: select * from test; +------+------+-------+ | id | name | valid | +======+======+=======+ | 1 | 1 | null | | 2 | 2 | null | | 3 | null | null | +------+------+-------+ It works fine, but: select * from test where name is null; +----+------+-------+ | id | name | valid | +====+======+=======+ +----+------+-------+ id 3 should appear here. Furthermore: select * from test where name is not null; (mapi:monetdb://monetdb@192.168.254.31/reports2) Cannot register project ( select ( table(sys.test) [ test.id NOT NULL, test.name, test.valid ] COUNT ) [ clob "NULL" ! <= test.name ! <= clob "NULL" ] ) [ test.id NOT NULL, test.name, test.valid ] REMOTE mapi:monetdb://.../... select * from test where valid is null; illegal input, not a JSON header (got '') and node1 is crashed (need : monetdb start farm). After downgrading on ubuntu 14.04 to version of 2015 (SP4) this scenraio works fine. Thanks, SG

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Table size does not decrease despite records deletion
by Manish gupta 26 Mar '17

26 Mar '17

Dear All, Is there a way to truncate the table size when deleting some of the records? In my application, I delete and insert ~1 million records daily. But effectively, it should result in few hundreds additional records. But, I see the size of the table increases by a millions ( that can be seen in storage(), as well as hard disk size ). While the "select count(*) from table" reflects correct number. Is there a way, I can stop increase in table size in my scheme? Regards, Manish

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Memory profiling of monet database
by Manish gupta 24 Mar '17

24 Mar '17

Dear all, I am looking at some memory profiling of monet database. Basically, the database size at disk is ~160 GB ( Although I am not very convinced with this big data size, there are 200M records with ~70 columns distributed among two big tables and several smaller ( relatively ) tables) . Right now, I have 64GB physical RAM dedicated machine for this database, but soon after firing queries on these tables ( with all sort of permutations on columns, but no joins between tables ), the memory is almost fully occupied, and resource crunch kills the performance. Is there any utility, which shows which all columns are in-memory and what is the size? And better some setting through which I can guide which columns should remain in memory and which should immediately trimmed after query returns? I am using windows 16 core machine on 64 bit architecture. Regards, Manish

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