Date: 2015-10-07 17:48:33 +0200
From: @swingbit
To: SQL devs <>
Version: 11.19.9 (Oct2014-SP2)
CC: @njnes

Last updated: 2016-01-15 11:38:03 +0100

Comment 21319

Date: 2015-10-07 17:48:33 +0200
From: @swingbit

User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/44.0.2403.157 Safari/537.36
Build Identifier:

*** BACKGRUND

I have an UDF that is used to produce a table for each row in input, and concatenate the output.

• SQL signature:
  create function tokenize(id integer, s string)
  returns table (id integer, token string)
  external name str."UTF8tokenize";

• MAL signature:
  command batstr.UTF8tokenize(id:bat[:oid,:int],s:bat[:oid,:str]) (:bat[:oid,:int],:bat[:oid,:str])
  address STRbat_utf8_tokenize_id;

Due to this UDF, it is not trivial to make this issue reproducible, but if this description is not enough to identify the problem, then I can share everything.

The UDF is used this way:

sql>CREATE TABLE ss (id INT, s CLOB);
operation successful (0.439ms)
sql>
sql>INSERT INTO ss VALUES (0,'one two');
1 affected row (0.377ms)
sql>INSERT INTO ss VALUES (1,'three four');
1 affected row (0.098ms)
sql>
sql>SELECT * FROM tokenize( (SELECT id, s FROM ss) );
+------+-------+
| id | token |
+======+=======+
| 0 | one |
| 0 | two |
| 1 | three |
| 1 | four |
+------+-------+
4 tuples (1.277ms)

This works.

*** ISSUE

Now, If I add a simple selection on token:

SELECT *
FROM tokenize( (SELECT id, s FROM ss) )
WHERE length(token) > 5;

then the server seems to hang indefinitely.

gdb suggests that it hangs in opt_pushselect. My wild guess is that it gets stuck while trying to push the select down the innermost selection (the input of the tokenize function). I tried with a standard table function, which takes no parameters and returns a table. No problem in that case.

The gdb session:

(gdb) thread apply all bt

Thread 12 (Thread 0x7f6b69ca9700 (LWP 20945)):
0 0x000000394ccf9063 in select () from /lib64/libc.so.6
1 0x00007f6b70ef5863 in MT_sleep_ms (ms=25) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_posix.c:1085
2 0x00007f6b714d43fa in profilerHeartbeat (dummy=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_profiler.c:980
3 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
4 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 11 (Thread 0x7f6b681b1700 (LWP 20946)):
0 0x000000394ccf9063 in select () from /lib64/libc.so.6
1 0x00007f6b715d8918 in SERVERlistenThread (Sock=0x279f5f0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/modules/mal/mal_mapi.c:234
2 0x00007f6b70ef3854 in thread_starter (arg=0x279f680) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_system.c:458
3 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
4 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 10 (Thread 0x7f6b67fb0700 (LWP 20947)):
0 0x000000394ccf9063 in select () from /lib64/libc.so.6
1 0x00007f6b70ef5863 in MT_sleep_ms (ms=50) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_posix.c:1085
2 0x00007f6b68fcf64c in store_manager () at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/sql/storage/store.c:1598
3 0x00007f6b68f40d2d in mvc_logmanager () at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/sql/server/sql_mvc.c:133
4 0x00007f6b70ef3854 in thread_starter (arg=0x2980800) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_system.c:458
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 9 (Thread 0x7f6b67daf700 (LWP 20950)):
0 0x00007f6b716d1149 in OPTpushselectImplementation (cntxt=0x7f6b69cb0328, mb=0x7f6b581260a0, stk=0x0, pci=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/optimizer/opt_pushselect.c:220
1 0x00007f6b716d3808 in OPTwrapper (cntxt=0x7f6b69cb0328, mb=0x7f6b581260a0, stk=0x0, p=0x7f6b5815c7a0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/optimizer/opt_wrapper.c:149
2 0x00007f6b716ce680 in optimizeMALBlock (cntxt=0x7f6b69cb0328, mb=0x7f6b581260a0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/optimizer/opt_support.c:262
3 0x00007f6b68ec4289 in addQueryToCache (c=0x7f6b69cb0328) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/sql/backends/monet5/sql_optimizer.c:294
4 0x00007f6b68ec1e18 in backend_dumpproc (be=0x7f6b580eafa0, c=0x7f6b69cb0328, cq=0x7f6b5811bb30, s=0x7f6b58107960) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/sql/backends/monet5/sql_gencode.c:2804
5 0x00007f6b68e8e1ae in SQLparser (c=0x7f6b69cb0328) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/sql/backends/monet5/sql_scenario.c:1206
6 0x00007f6b714e0bb0 in runPhase (c=0x7f6b69cb0328, phase=1) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_scenario.c:515
7 0x00007f6b714e0d57 in runScenarioBody (c=0x7f6b69cb0328) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_scenario.c:550
8 0x00007f6b714e0f02 in runScenario (c=0x7f6b69cb0328) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_scenario.c:579
9 0x00007f6b714e283e in MSserveClient (dummy=0x7f6b69cb0328) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_session.c:439
10 0x00007f6b714e2237 in MSscheduleClient (command=0x7f6b580008d0 "\001", challenge=0x7f6b67daedf0 "00lSGLgI", fin=0x7f6b58006b40, fout=0x7f6b580049c0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_session.c:319
11 0x00007f6b715d86e0 in doChallenge (data=0x7f6b600008d0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/modules/mal/mal_mapi.c:184
12 0x00007f6b70ef3854 in thread_starter (arg=0x7f6b60000a50) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_system.c:458
13 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
14 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 8 (Thread 0x7f6b67aae700 (LWP 20951)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b71934880 ) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 7 (Thread 0x7f6b678ad700 (LWP 20952)):
---Type to continue, or q to quit---
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b719348c0 <workers+64>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 6 (Thread 0x7f6b676ac700 (LWP 20953)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b71934900 <workers+128>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 5 (Thread 0x7f6b674ab700 (LWP 20954)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b71934940 <workers+192>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 4 (Thread 0x7f6b672aa700 (LWP 20955)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b71934980 <workers+256>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 3 (Thread 0x7f6b670a9700 (LWP 20956)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b719349c0 <workers+320>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f6b66ca7700 (LWP 20958)):
0 0x000000394d00e829 in do_futex_wait.constprop () from /lib64/libpthread.so.0
1 0x000000394d00e8c4 in __new_sem_wait_slow.constprop.0 () from /lib64/libpthread.so.0
2 0x000000394d00e96a in sem_wait@@GLIBC_2.2.5 () from /lib64/libpthread.so.0
3 0x00007f6b714b9c30 in q_dequeue (q=0x7f6b5811bbc0, cntxt=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:213
4 0x00007f6b714ba64b in DFLOWworker (T=0x7f6b71934a40 <workers+448>) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/mal/mal_dataflow.c:333
5 0x000000394d007555 in start_thread () from /lib64/libpthread.so.0
---Type to continue, or q to quit---
6 0x000000394cd02b9d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f6b70678800 (LWP 20944)):
0 0x000000394ccf9063 in select () from /lib64/libc.so.6
1 0x00007f6b70ef5863 in MT_sleep_ms (ms=5000) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/gdk/gdk_posix.c:1085
2 0x0000000000403ec4 in main (argc=20, av=0x7ffcbaed5dc8) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/tools/mserver/mserver5.c:668
(gdb) thread 9
[Switching to thread 9 (Thread 0x7f6b67daf700 (LWP 20950))]
0 0x00007f6b716d1149 in OPTpushselectImplementation (cntxt=0x7f6b69cb0328, mb=0x7f6b581260a0, stk=0x0, pci=0x0) at /opt/spinque/MonetDBServer/MonetDB.Spinque_Jul2015/src/monetdb5/optimizer/opt_pushselect.c:220
220 } else if (isMapOp(q) && q->argc >= 2 && isaBatType(getArgType(mb, q, 1))) {
(gdb) l
215 InstrPtr s = old[vars[i1]];
216 if (getModuleId(s) == sqlRef && getFunctionId(s) == tidRef)
217 tid = getArg(q, 1);
218 }
219 break;
220 } else if (isMapOp(q) && q->argc >= 2 && isaBatType(getArgType(mb, q, 1))) {
221 int i1 = getArg(q, 1);
222 q = old[vars[i1]];
223 } else if (isMapOp(q) && q->argc >= 3 && isaBatType(getArgType(mb, q, 2))) {
224 int i2 = getArg(q, 2);

Reproducible: Always

$ mserver5 --version
MonetDB 5 server v11.21.6 (64-bit, 64-bit oids, 128-bit integers)
This is an unreleased version
Copyright (c) 1993-July 2008 CWI
Copyright (c) August 2008-2015 MonetDB B.V., all rights reserved
Visit http://www.monetdb.org/ for further information
Found 15.6GiB available memory, 8 available cpu cores
Libraries:
libpcre: 8.37 2015-04-28 (compiled with 8.37)
openssl: OpenSSL 1.0.1k 8 Jan 2015 (compiled with OpenSSL 1.0.1k-fips 8 Jan 2015)
libxml2: 2.9.2 (compiled with 2.9.2)
Compiled by: roberto@photon.hq.spinque.com (x86_64-unknown-linux-gnu)
Compilation: gcc -g -Werror -Wall -Wextra -W -Werror-implicit-function-declaration -Wpointer-arith -Wdeclaration-after-statement -Wundef -Wformat=2 -Wno-format-nonliteral -Winit-self -Winvalid-pch -Wmissing-declarations -Wmissing-format-attribute -Wmissing-prototypes -Wold-style-definition -Wpacked -Wunknown-pragmas -Wvariadic-macros -fstack-protector-all -Wstack-protector -Wpacked-bitfield-compat -Wsync-nand -Wjump-misses-init -Wmissing-include-dirs -Wlogical-op -Wunreachable-code
Linking : /usr/bin/ld -m elf_x86_64

Comment 21691

Date: 2015-12-24 22:36:44 +0100
From: MonetDB Mercurial Repository <>

Changeset 9633f26d33e6 made by Niels Nes niels@cwi.nl in the MonetDB repo, refers to this bug.

For complete details, see http//devmonetdborg/hg/MonetDB?cmd=changeset;node=9633f26d33e6

Changeset description:

protect against multi-output multiplex functions, solves bug #3817

Comment 21692

Date: 2015-12-24 22:37:08 +0100
From: @njnes

fixed in Jul 2015 branch