Date: 2019-08-18 14:50:39 +0200
From: @drstmane
To: SQL devs <>
Version: 11.33.3 (Apr2019)
CC: @PedroTadim

Last updated: 2019-09-02 16:05:26 +0200

Comment 27230

Date: 2019-08-18 14:50:39 +0200
From: @drstmane

when trying to restart the MonetDB server (mserver5) after having dropped with "cascade" a column that holds a (unique) constraint,
the restart fails with a segfault (non-debug build), respectively aborts with

mserver5: .../MonetDB/sql/storage/store.c:276: load_keycolumn: Assertion `kc->c' failed.

(debug build)

Comment 27231

Date: 2019-08-18 14:56:23 +0200
From: @drstmane

This bug appears with Apr2019_release (Apr2019_3), Apr2019_SP1_release (Apr2019_7) and current head of Apr2019 branch (changeset 6eda988176b3).

Comment 27232

Date: 2019-08-18 15:01:22 +0200
From: @drstmane

Created attachment 625
test script

Attached file: Bug-6749.sh (application/x-shellscript, 1680 bytes)
Description: test script

Comment 27234

Date: 2019-08-19 10:05:02 +0200
From: MonetDB Mercurial Repository <>

Changeset 965b25376303 made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=965b25376303

Changeset description:

Added test for bug #6749

Comment 27235

Date: 2019-08-19 13:47:37 +0200
From: MonetDB Mercurial Repository <>

Changeset 925022b81bac made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=925022b81bac

Changeset description:

Fix for bug #6749 (i.e. when copying the key definition to the transaction's table, create a dependency for unique keys as well)

Comment 27239

Date: 2019-08-19 17:13:36 +0200
From: @drstmane

Hi Pedro,

thanks for your fix!

While this indeed seems to work for the provided test case,
in my larger case (on propriatory data),
mserver5 5 now segfaults during the "drop columns .. cascade" ...

I still need to understand what extra code (or different data?) in my larger test case triggers this segfault ...

Comment 27240

Date: 2019-08-19 17:41:23 +0200
From: @drstmane

segfault when drop is in same transaction as create:

$ cat Bug-6749.sql
start transaction;
create table t (a int, b int, c int);
alter table t add unique (b);
\d t
select * from t;
alter table t drop column b cascade;
\d t
select * from t;
commit;
select * from t;
\d t
drop table t;
\d t
select * from t;

$ mclient -p50505 -dMyDB -i -e < Bug-6749.sql
start transaction;
auto commit mode: off
create table t (a int, b int, c int);
operation successful
alter table t add unique (b);
operation successful
CREATE TABLE "sys"."t" (
"a" INTEGER,
"b" INTEGER,
"c" INTEGER,
CONSTRAINT "t_b_unique" UNIQUE ("b")
);
select * from t;
+---+---+---+
| a | b | c |
+===+===+===+
+---+---+---+
0 tuples

Thread 61 "mserver5" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffd2199700 (LWP 7206)]
sys_drop_key (tr=0x25d4640, k=0x26da830, drop_action=1) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:4366
4366 for (n = k->columns->h; n; n = n->next) {
Missing separate debuginfos, use: dnf debuginfo-install R-core-3.5.0-4.fc28.x86_64 SuperLU-5.2.0-7.fc28.x86_64 armadillo-8.600.0-1.fc28.x86_64 arpack-3.5.0-6.fc28.x86_64 atlas-3.10.3-5.fc28.x86_64 blas-3.8.0-9.fc28.x86_64 boost-atomic-1.66.0-8.fc28.x86_64 boost-chrono-1.66.0-8.fc28.x86_64 boost-date-time-1.66.0-8.fc28.x86_64 boost-filesystem-1.66.0-8.fc28.x86_64 boost-iostreams-1.66.0-8.fc28.x86_64 boost-program-options-1.66.0-8.fc28.x86_64 boost-regex-1.66.0-8.fc28.x86_64 boost-system-1.66.0-8.fc28.x86_64 boost-thread-1.66.0-8.fc28.x86_64 bzip2-libs-1.0.6-26.fc28.x86_64 cfitsio-3.430-1.fc28.x86_64 cyrus-sasl-lib-2.1.27-0.2rc7.fc28.x86_64 expat-2.2.5-3.fc28.x86_64 fontconfig-2.13.0-4.fc28.x86_64 freetype-2.8-10.fc28.x86_64 freexl-1.0.5-1.fc28.x86_64 gdal-libs-2.2.4-2.fc28.x86_64 geos-3.6.1-8.fc28.x86_64 giflib-5.1.4-1.fc28.x86_64 hdf5-1.8.20-3.fc28.x86_64 jasper-libs-2.0.14-5.fc28.x86_64 jbigkit-libs-2.1-12.fc28.x86_64 json-c-0.13.1-2.fc28.x86_64 keyutils-libs-1.5.10-6.fc28.x86_64 krb5-libs-1.16.1-13.fc28.x86_64 lapack-3.8.0-9.fc28.x86_64 laszip-2.2.0-10.fc28.x86_64 lcms2-2.9-2.fc28.x86_64 libaec-1.0.2-3.fc28.x86_64 libatomic_ops-7.6.2-3.fc28.x86_64 libcom_err-1.44.2-0.fc28.x86_64 libcurl-7.59.0-5.fc28.x86_64 libdap-3.18.3-4.fc27.x86_64 libgcc-8.1.1-5.fc28.x86_64 libgeotiff-1.4.0-12.fc28.x86_64 libgfortran-8.1.1-5.fc28.x86_64 libgomp-8.1.1-5.fc28.x86_64 libgta-1.0.7-7.fc28.x86_64 libicu-60.2-2.fc28.x86_64 libidn2-2.0.5-1.fc28.x86_64 libjpeg-turbo-1.5.3-6.fc28.x86_64 libkml-1.3.0-10.fc28.x86_64 liblas-1.8.0-21.fc28.x86_64 libnghttp2-1.32.0-1.fc28.x86_64 libpng-1.6.34-6.fc28.x86_64 libpsl-0.20.2-2.fc28.x86_64 libquadmath-8.1.1-5.fc28.x86_64 libselinux-2.8-1.fc28.x86_64 libspatialite-4.3.0a-8.fc28.x86_64 libssh-0.7.5-7.fc28.x86_64 libstdc++-8.1.1-5.fc28.x86_64 libtiff-4.0.9-10.fc28.x86_64 libtirpc-1.0.3-3.rc2.fc28.x86_64 libtool-ltdl-2.4.6-24.fc28.x86_64 libunistring-0.9.10-1.fc28.x86_64 libuuid-2.32.1-1.fc28.x86_64 libwebp-1.0.0-1.fc28.x86_64 libxcrypt-4.1.1-4.fc28.x86_64 libxml2-2.9.8-4.fc28.x86_64 lz4-libs-1.8.1.2-4.fc28.x86_64 mariadb-connector-c-3.0.5-1.fc28.x86_64 minizip-1.2.11-8.fc28.x86_64 ncurses-libs-6.1-5.20180224.fc28.x86_64 netcdf-4.4.1.1-9.fc28.x86_64 nspr-4.19.0-1.fc28.x86_64 nss-3.38.0-1.0.fc28.x86_64 nss-util-3.38.0-1.0.fc28.x86_64 ogdi-3.2.1-1.fc28.x86_64 openblas-Rblas-0.3.2-1.fc28.x86_64 openblas-openmp-0.3.2-1.fc28.x86_64 openblas-threads-0.3.2-1.fc28.x86_64 openjpeg2-2.3.0-6.fc28.x86_64 openldap-2.4.46-2.fc28.x86_64 openssl-libs-1.1.0h-3.fc28.x86_64 pcre-8.42-2.fc28.x86_64 pcre2-10.31-8.fc28.x86_64 poppler-0.62.0-4.fc28.x86_64 postgresql-libs-10.4-1.fc28.x86_64 proj-4.9.3-6.fc28.x86_64 readline-7.0-11.fc28.x86_64 snappy-1.1.7-5.fc28.x86_64 sqlite-libs-3.22.0-4.fc28.x86_64 tre-0.8.0-22.20140228gitc2f5d13.fc28.x86_64 unixODBC-2.3.5-3.fc28.x86_64 uriparser-0.8.5-1.fc28.x86_64 xerces-c-3.2.1-1.fc28.x86_64 xz-libs-5.2.4-2.fc28.x86_64 zlib-1.2.11-8.fc28.x86_64
(gdb) bt
0 sys_drop_key (tr=0x25d4640, k=0x26da830, drop_action=1) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:4366
1 0x00007fffeebd7320 in sql_trans_drop_key (tr=0x25d4640, s=0x2650860, id=8978, drop_action=1) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:6191
2 0x00007fffeebccf32 in sql_trans_drop_all_dependencies (tr=0x25d4640, s=0x2650860, id=8975, type=3) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:4270
3 0x00007fffeebce0d6 in sys_drop_column (tr=0x25d4640, col=0x26da480, drop_action=2) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:4505
4 0x00007fffeebd4da3 in sql_trans_drop_column (tr=0x25d4640, t=0x26da180, id=8975, drop_action=2) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/storage/store.c:5731
5 0x00007fffeeaf05b8 in mvc_drop_column (m=0x7fff4000b750, t=0x26da180, col=0x26da480, drop_action=1) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/server/sql_mvc.c:1394
6 0x00007fffeea6e777 in alter_table (cntxt=0x7fffefe4d380, sql=0x7fff4000b750, sname=0x7fff40136ae0 "sys", t=0x7fff40229b70) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/backends/monet5/sql_cat.c:847
7 0x00007fffeea70878 in SQLalter_table (cntxt=0x7fffefe4d380, mb=0x7fff401e1a00, stk=0x7fff40134ab0, pci=0x7fff40135980) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/backends/monet5/sql_cat.c:1140
8 0x00007ffff79ccd57 in runMALsequence (cntxt=0x7fffefe4d380, mb=0x7fff401e1a00, startpc=1, stoppc=0, stk=0x7fff40134ab0, env=0x0, pcicaller=0x0) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_interpreter.c:647
9 0x00007ffff79cb3e1 in runMAL (cntxt=0x7fffefe4d380, mb=0x7fff401e1a00, mbcaller=0x0, env=0x0) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_interpreter.c:336
10 0x00007fffeea451b2 in SQLrun (c=0x7fffefe4d380, be=0x7fff40004500, m=0x7fff4000b750) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/backends/monet5/sql_execute.c:384
11 0x00007fffeea46ce0 in SQLengineIntern (c=0x7fffefe4d380, be=0x7fff40004500) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/backends/monet5/sql_execute.c:809
12 0x00007fffeea433fc in SQLengine (c=0x7fffefe4d380) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/sql/backends/monet5/sql_scenario.c:1381
13 0x00007ffff79f9601 in runPhase (c=0x7fffefe4d380, phase=4) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_scenario.c:517
14 0x00007ffff79f979d in runScenarioBody (c=0x7fffefe4d380, once=0) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_scenario.c:547
15 0x00007ffff79f99ce in runScenario (c=0x7fffefe4d380, once=0) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_scenario.c:580
16 0x00007ffff79fb7e1 in MSserveClient (c=0x7fffefe4d380) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_session.c:525
17 0x00007ffff79fb2a6 in MSscheduleClient (command=0x7fff40000b30 "0B", challenge=0x7fffd2198cbb "T1fEySDwZ", fin=0x7fff40002b90, fout=0x7fffcc002da0, protocol=PROTOCOL_9, blocksize=8190)
at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/mal/mal_session.c:403
18 0x00007ffff7aa8909 in doChallenge (data=0x7fffcc000b30) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/monetdb5/modules/mal/mal_mapi.c:271
19 0x00007ffff753dcfb in THRstarter (a=0x7fffcc004e90) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/gdk/gdk_utils.c:1415
20 0x00007ffff75b7d61 in thread_starter (arg=0x2212e00) at /export/scratch1/home/manegold//Monet/release/source/MonetDB/gdk/gdk_system.c:650
21 0x00007ffff4611594 in start_thread () from /lib64/libpthread.so.0
22 0x00007ffff43450df in clone () from /lib64/libc.so.6
(gdb) l
4361
4362 if (is_oid_nil(rid))
4363 return ;
4364 table_funcs.table_delete(tr, syskey, rid);
4365
4366 for (n = k->columns->h; n; n = n->next) {
4367 sql_kc kc = n->data;
4368 sys_drop_kc(tr, k, kc);
4369 }
4370 / remove key from schema */
(gdb) p rid
$1 = 24
(gdb) p k
$2 = (sql_key *) 0x26da830
(gdb) p *k
$3 = {base = {wtime = 0, rtime = 0, stime = 0, allocated = 0, flags = 1, refcnt = 1, id = 8978, name = 0x26da890 "t_b_unique"}, type = ukey, idx = 0x26da620, columns = 0x0, t = 0x26da180, drop_action = 0}
(gdb) p k->columns
$4 = (struct list *) 0x0
(gdb)

Comment 27242

Date: 2019-08-19 20:01:04 +0200
From: MonetDB Mercurial Repository <>

Changeset ccf704516cc6 made by Pedro Ferreira pedro.ferreira@monetdbsolutions.com in the MonetDB repo, refers to this bug.

For complete details, see https//devmonetdborg/hg/MonetDB?cmd=changeset;node=ccf704516cc6

Changeset description:

More fixes for bug #6749 (i.e. when dropping a key, clean the key from the table's keyset only after removing the underlying storage information (dependant action))

Comment 27243

Date: 2019-08-19 20:03:51 +0200
From: @PedroTadim

Thank you Dr. Stefan for your reports. I just committed a fix for your latest issue.