ctdb-vacuum: Stagger vacuuming child processes

This prevents multiple child processes being forked at the same time
for vacuuming TDBs.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Martin Schwenke <martin@meltin.net>

diff --git a/ctdb/server/ctdb_vacuum.c b/ctdb/server/ctdb_vacuum.c
index 8cd37aa8315e08322ee7f04c9539f659863814da..0f1de19245d039e686996f1aeaff0f32b0572440 100644 (file)
--- a/ctdb/server/ctdb_vacuum.c
+++ b/ctdb/server/ctdb_vacuum.c
@@ -1451,6 +1451,17 @@ ctdb_vacuum_event(struct event_context *ev, struct timed_event *te,
                return;
        }
 
+       /* Do not allow multiple vacuuming child processes to be active at the
+        * same time.  If there is vacuuming child process active, delay
+        * new vacuuming event to stagger vacuuming events.
+        */
+       if (ctdb->vacuumers != NULL) {
+               event_add_timed(ctdb->ev, vacuum_handle,
+                               timeval_current_ofs(0, 500*1000),
+                               ctdb_vacuum_event, vacuum_handle);
+               return;
+       }
+
        child_ctx = talloc(vacuum_handle, struct ctdb_vacuum_child_context);
        if (child_ctx == NULL) {
                DEBUG(DEBUG_CRIT, (__location__ " Failed to allocate child context for vacuuming of %s\n", ctdb_db->db_name));