KafkaCDC causes segfault when processing geometry datatype events

Summary
KafkaCDC aborts when processing row events containing spatial geometry columns (POINT)

Environment
MaxScale: 23.02.17

MariaDB Server:

• 11.4.12
• 10.11.x

Kafka: 4.3.0

OS:
Rocky Linux 9.8 (Blue Onyx)

MariaDB Configuration:

```
[mariadbd]
server_id=1
log-bin
binlog_format=ROW
binlog_row_image=FULL
```

CDC Service Configuration

```
[CDC-Service]
type=service
router=kafkacdc
servers=server1
user=<username>
password=<password>
bootstrap_servers=cdc_broker:9092
topic=cdc-topic
match=cdc_test[.].*
```

Description

KafkaCDC aborts while processing row events containing geometry data types.

The issue was isolated from a larger schema by progressively reducing the test environment until a minimal reproducer was found.

CDC functions correctly for ordinary scalar types such as INT and VARCHAR. The failure only occurs when a row event contains a geometry value.

Expected Behavior

KafkaCDC should either:

• Successfully publish row events containing geometry values, or
• Reject unsupported geometry types with a logged error.

In either case, MaxScale should continue running.

Actual Behavior

When a row containing a geometry value is inserted, MaxScale aborts with fatal signal 6 while processing the row event.

Reproduction Steps
Create a test database:

```
CREATE DATABASE cdc_test;
USE cdc_test;
```

Create a table containing a geometry column:

```
CREATE TABLE t1 (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
geom POINT
);
```

The table creation succeeds and does not trigger the failure.

Insert a geometry value:

```
INSERT INTO t1 (geom)
VALUES (ST_GeomFromText('POINT(1 2)'));
```

MaxScale aborts while processing the resulting row event.

Control Case

The same KafkaCDC configuration functions correctly when only scalar data types are used.

Example:

```
CREATE TABLE scalar_test (
id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
msg VARCHAR(64)
);

INSERT INTO scalar_test (msg)
VALUES ('hello');
```

In this case:

• CDC topic is created successfully
• CDC messages are published successfully
• MaxScale remains running

Stack Trace

```
MaxScale 23.02.17 received fatal signal 6. Commit ID: e98e370325d228dd2ad3f885e78c15a1f059e56f, System name: Linux, Release string: Rocky Linux 9.8 (Blue Onyx), Thread: cdc::Replicator

nm: 'maxscale': No such file
addr2line: 'maxscale': No such file
nm: 'maxscale': No such file
addr2line: 'maxscale': No such file
addr2line: 'maxscale': No such file

maxscale(_ZN7maxbase15dump_stacktraceESt8functionIFvPKcS2_EE+0x2b):
maxscale(_ZN7maxbase15dump_stacktraceEPFvPKcS1_E+0x42):
maxscale():
/lib64/libc.so.6(+0x3fc60): ??:?
/lib64/libc.so.6(+0x8d21c): ??:?
/lib64/libc.so.6(raise+0x16): :?
/usr/lib64/maxscale/libreplicator.so.1.0.0(ZN3Rpl22process_row_event_dataERK5TablePhS3_S3+0x1d12): server/modules/routing/replicator/rpl.cc:1876
/usr/lib64/maxscale/libreplicator.so.1.0.0(_ZN3Rpl16handle_row_eventEP10REP_HEADERPh+0x546): /usr/include/c++/11/bits/unique_ptr.h:173
/usr/lib64/maxscale/libreplicator.so.1.0.0(_ZN3Rpl12handle_eventE10REP_HEADERPh+0x5f): server/modules/routing/replicator/rpl.cc:2234
/usr/lib64/maxscale/libreplicator.so.1.0.0(_ZN3cdc10Replicator3Imp17process_one_eventERSt10unique_ptrI20st_mariadb_rpl_eventSt8functionIFvPS3_EEE+0xbf): server/modules/routing/replicator/replicator.cc:606
/usr/lib64/maxscale/libreplicator.so.1.0.0(_ZN3cdc10Replicator3Imp14process_eventsEv+0x34e): /usr/include/c++/11/bits/atomic_base.h:488
/lib64/libstdc++.so.6(+0xdbae4): ??:?
/lib64/libc.so.6(+0x8b3f9): ??:?
/lib64/libc.so.6(+0x1105d0): :?

Writing core dump.
/app/run_maxscale.sh: line 46: 4 Aborted (core dumped)
```

Additional Notes

The issue reproduces with a simple POINT column and does not require any complex geometry structures.

The failure does not occur during:

• Database creation
• Table creation
• Kafka broker startup
• CDC service startup

The failure occurs only when KafkaCDC processes a row event containing a geometry value.