Skip to content

Document DNS cache bypass limitation for resolution_family #5558

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
renecannao wants to merge 1 commit into
base: v3.0
Choose a base branch
from
+4 −0
Open

Document DNS cache bypass limitation for resolution_family #5558

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions lib/mysql_connection.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -959,6 +959,10 @@ char * MySQL_Connection::connect_start_DNS_lookup() {
host_ip = connected_host_details.ip;
}
else {
// NOTE: DNS cache miss — hostname is passed directly to
// mysql_real_connect which resolves via the MariaDB client library
// using AF_UNSPEC. The mysql-resolution_family setting does NOT
// apply here; it only governs the DNS cache resolver thread.
Comment on lines +962 to +965

@gemini-code-assist gemini-code-assist Bot Apr 1, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

medium

The comment states that mysql-resolution_family governs the DNS cache resolver thread. However, the implementation of monitor_dns_resolver_thread in lib/MySQL_Monitor.cpp appears to use a hardcoded AF_UNSPEC for the address family:

// lib/MySQL_Monitor.cpp:4675
hints.ai_family = AF_UNSPEC;

This makes the comment potentially misleading as it suggests mysql-resolution_family is being used by the resolver thread when it is not. To avoid confusion, the comment should be updated to accurately reflect the current implementation.

Comment on lines +962 to +965

Copilot AI Apr 1, 2026

Copy link

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The new comment refers to a mysql-resolution_family setting and says it “only governs the DNS cache resolver thread”, but in this branch the DNS resolver thread still hardcodes hints.ai_family = AF_UNSPEC (see lib/MySQL_Monitor.cpp:4676) and there are no other references to mysql-resolution_family in the repo. Either stack this PR on top of the change that introduces that setting, or reword this note to avoid documenting a config option that doesn’t exist here. Also consider naming the actual async API used here (mysql_real_connect_start) to match the code path.

Copilot uses AI. Check for mistakes.
host_ip = parent->address;
}
return host_ip;
Expand Down
Loading