Issue #3846: Release GIL during calls to sqlite3_prepare. This improves concurrent access to the same database file from multiple threads/processes.
diff --git a/Modules/_sqlite/statement.c b/Modules/_sqlite/statement.c
index dae83d4..f200c56 100644
--- a/Modules/_sqlite/statement.c
+++ b/Modules/_sqlite/statement.c
@@ -79,11 +79,13 @@
 
     sql_cstr = PyString_AsString(sql_str);
 
+    Py_BEGIN_ALLOW_THREADS
     rc = sqlite3_prepare(connection->db,
                          sql_cstr,
                          -1,
                          &self->st,
                          &tail);
+    Py_END_ALLOW_THREADS
 
     self->db = connection->db;
 
@@ -328,11 +330,13 @@
 
     sql_cstr = PyString_AsString(self->sql);
 
+    Py_BEGIN_ALLOW_THREADS
     rc = sqlite3_prepare(self->db,
                          sql_cstr,
                          -1,
                          &new_st,
                          &tail);
+    Py_END_ALLOW_THREADS
 
     if (rc == SQLITE_OK) {
         /* The efficient sqlite3_transfer_bindings is only available in SQLite