jcloude/debugging/mariadb.md

Generate coredump on the affected MariaDB server.

pgrep mariadbd | xargs gcore

This will create a core.<x> where <x> is the pid of MariaDB proces. The core file is likely to be ~5G in size. Compress it.

gzip core.<x>

Compressed core.<x>.gz should be around `~5OM.

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Build the MariaDB debug container.

docker build -t mariadb-debug:10.6 -f mariadb.Dockerfile .

This has the latest MariaDB 10.6 with all the debug symbols necessary to generate a useful stacktrace.

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Copy the coredump locally for debugging.

scp -C -oProxyCommand="ssh -o 'ForwardAgent yes' frappe@frappe.cloud 'ssh-add && nc %h %p'" root@m<y>-mumbai.frappe.cloud:/root/core.<x>.gz .

Extract the compressed core file.

gzip -d core.<x>.gz

You'll get the core.<x> file back. Generate complete stacktrace.

docker run -v ./core.<x>:/core -v --rm -it mariadb-debug:10.6 gdb --batch --eval-command="set print frame-arguments all" --eval-command="thread apply all bt full" /usr/sbin/mariadbd /core > stack.txt

or launch gdb.

docker run -v ./core.<x>:/core -v --rm -it mariadb-debug:10.6 gdb /usr/sbin/mariadbd /core