An issue in the rel_deps component of MonetDB Server v11.45.17 and v11.46.0 allows attackers to cause a Denial of Service (DoS) via crafted SQL statements.
**Describe the bug**
MonetDB server 11.46.0 crashes in `rel_deps` after executing SQL statements through mclient.

**To Reproduce**
```sql
CREATE VIEW t2 AS SELECT 1 UNION ALL SELECT 1;
CREATE VIEW v2 AS SELECT * FROM t2;
```

**Expected behavior**
Executing statements successfully or throwing errors, instead of breaking down the whole MonetDB server.

**Backtrace**
```
#0 0x7fc48d1c68d1 (rel_deps+0x191)
#1 0x7fc48d1c6997 (rel_deps+0x257)
#2 0x7fc48d1c670a (rel_dependencies+0x4a)
#3 0x7fc48d072b25 (create_table_or_view+0x865)
#4 0x7fc48d0aab57 (SQLcreate_view+0xe7)
#5 0x7fc48d404c63 (runMALsequence+0x763)
#6 0x7fc48d40431e (runMAL+0x9e)
#7 0x7fc48d08b9f9 (SQLrun+0xd9)
#8 0x7fc48d08cbee (SQLengineIntern+0x4e)
#9 0x7fc48d08a8c2 (SQLengine_+0x5e2)
#10 0x7fc48d089343 (SQLengine+0x23)
#11 0x7fc48d4186cf (runScenario+0x4f)
#12 0x7fc48d41916c (MSscheduleClient+0x68c)
#13 0x7fc48d4c0c2b (doChallenge+0xfb)
#14 0x7fc48db3fba0 (THRstarter+0x100)
#15 0x7fc48dbafcc4 (thread_starter+0x34)
#16 0x7fc48cf24609 (start_thread+0xd9)
#17 0x7fc48ce49133 (clone+0x43)
```

**Software versions**
 - MonetDB server version: 11.46.0 (hg id: 63a42c2) (pulled from the master branch)
 - MonetDB client version: mclient, version 11.48.0 (hg id: 63a42c2)
 - OS and version: ubuntu 20.04
 - Self-installed and compiled. The command line of compilation: `CC=clang-12 CXX=clang++-12 cmake /root/monetdb_master -DCMAKE_BUILD_TYPE=RelWithDebInfo`

**Issue labeling**
bug

**Additional context**
The MonetDB here runs in-memory database. The command line of starting MonetDB server is `mserver5 --in-memory`.
MonetDB server 11.46.0 crashes in `rel_deps`
This is a GitHub Issue
repo:MonetDB
owner:MonetDB
Title : MonetDB server 11.46.0 crashes in `rel_deps`
Issue date:

--- start body ---
**Describe the bug**
MonetDB server 11.46.0 crashes in `rel_deps` after executing SQL statements through mclient.

**To Reproduce**
```sql
CREATE VIEW t2 AS SELECT 1 UNION ALL SELECT 1;
CREATE VIEW v2 AS SELECT * FROM t2;
```

**Expected behavior**
Executing statements successfully or throwing errors, instead of breaking down the whole MonetDB server.

**Backtrace**
```
#0 0x7fc48d1c68d1 (rel_deps+0x191)
#1 0x7fc48d1c6997 (rel_deps+0x257)
#2 0x7fc48d1c670a (rel_dependencies+0x4a)
#3 0x7fc48d072b25 (create_table_or_view+0x865)
#4 0x7fc48d0aab57 (SQLcreate_view+0xe7)
#5 0x7fc48d404c63 (runMALsequence+0x763)
#6 0x7fc48d40431e (runMAL+0x9e)
#7 0x7fc48d08b9f9 (SQLrun+0xd9)
#8 0x7fc48d08cbee (SQLengineIntern+0x4e)
#9 0x7fc48d08a8c2 (SQLengine_+0x5e2)
#10 0x7fc48d089343 (SQLengine+0x23)
#11 0x7fc48d4186cf (runScenario+0x4f)
#12 0x7fc48d41916c (MSscheduleClient+0x68c)
#13 0x7fc48d4c0c2b (doChallenge+0xfb)
#14 0x7fc48db3fba0 (THRstarter+0x100)
#15 0x7fc48dbafcc4 (thread_starter+0x34)
#16 0x7fc48cf24609 (start_thread+0xd9)
#17 0x7fc48ce49133 (clone+0x43)
```

**Software versions**
 - MonetDB server version: 11.46.0 (hg id: 63a42c2) (pulled from the master branch)
 - MonetDB client version: mclient, version 11.48.0 (hg id: 63a42c2)
 - OS and version: ubuntu 20.04
 - Self-installed and compiled. The command line of compilation: `CC=clang-12 CXX=clang++-12 cmake /root/monetdb_master -DCMAKE_BUILD_TYPE=RelWithDebInfo`

**Issue labeling**
bug

**Additional context**
The MonetDB here runs in-memory database. The command line of starting MonetDB server is `mserver5 --in-memory`.
--- end body ---
