Ruby threads blocked on calls to C functions

[dan-manges]

I think the C extension needs to use rb_thread_call_without_gvl to release the GVL while executing long running I/O. Otherwise, it will block other Ruby threads.

test script

require "duckdb"

t1 = Thread.new do
  loop do
    puts "[t1] #{Time.now}"
    sleep 1
  end
end

t2 = Thread.new do
  loop do
    puts "[t2] Running DuckDB"
    DuckDB::Database.open("/tmp/foo.duckdb") do |db|
      db.connect do |con|
        con.execute "SELECT SUM(random()) FROM range(1000000000);"
      end
    end
    sleep 3
  end
end

t1.join
t2.join

output

[t1] 2025-01-31 10:01:48 -0500
[t2] Running DuckDB
[t1] 2025-01-31 10:01:52 -0500
[t1] 2025-01-31 10:01:53 -0500
[t1] 2025-01-31 10:01:54 -0500
[t2] Running DuckDB
[t1] 2025-01-31 10:01:59 -0500
[t1] 2025-01-31 10:02:00 -0500
[t1] 2025-01-31 10:02:01 -0500
[t2] Running DuckDB
[t1] 2025-01-31 10:02:07 -0500