MariaDB 11.4.4 Crashes when querying a Spider table on a remote system with a distinct selection that is not a primary key.

When using MariaDB 11.4.4 with a link to a remote Spider table it will crash the DB when running a select distinct(non primary key field) from spider.table.

I have tested this on 11.4.3 and the query runs without any problem. I have found that the table you are querying needs to have more than 10K rows in order for the crash to occur.

To reproduce create a table on the spider database

Create table db1.tab1 (
id int(4) not null auto_increment,
status varchar(25) default null,
primary key (id) )
engine=InnoDB default charset=latin1;

Insert into the table a ten thousand entries. For my test I used a script to put an incrementing number into the status field.

On the main DB server create spider server entry

create or replace server dataNode1 foreign data wrapper mysql options (PORT 3306, HOST 'spiderDBhost', USER 'spideruser', PASSWORD 'password123');

Create the spider table.

create table db1.tab1 engine=SPIDER comment='wrapper "mysql", srv "dataNode1", table "tab1";

Running this query will cause 11.4.4 to crash:

Select distinct(status) from db1.tab1

It will error out with [ERROR] mysqld got signal 11;
Looking at /var/log/messages there is an entry reporting a segfault on ha_spider.so