diff options
| -rw-r--r-- | ctdb/server/ctdb_vacuum.c | 36 |
1 files changed, 31 insertions, 5 deletions
diff --git a/ctdb/server/ctdb_vacuum.c b/ctdb/server/ctdb_vacuum.c index 322d1b34ba..e30b6e857b 100644 --- a/ctdb/server/ctdb_vacuum.c +++ b/ctdb/server/ctdb_vacuum.c @@ -435,11 +435,37 @@ done: return 0; } -/* - * read-only traverse the database in order to find - * records that can be deleted and try to delete these - * records on the other nodes - * this executes in the child context +/** + * Vacuum a DB: + * - Always do the fast vacuuming run, which traverses + * the in-memory delete queue: these records have been + * scheduled for deletion. + * - Only if explicitly requested, the database is traversed + * in order to use the traditional heuristics on empty records + * to trigger deletion. + * This is done only every VacuumFastPathCount'th vacuuming run. + * + * The traverse runs fill two lists: + * + * - The delete_list: + * This is the list of empty records the current + * node is lmaster and dmaster for. These records are later + * deleted first on other nodes and then locally. + * + * The fast vacuuming run has a short cut for those records + * that have never been migrated with data: these records + * are immediately deleted locally, since they have left + * no trace on other nodes. + * + * - The vacuum_fetch lists + * (one for each other lmaster node): + * The records in this list are sent for deletion to + * their lmaster in a bulk VACUUM_FETCH message. + * + * The lmaster then migrates all these records to itelf + * so that they can be vacuumed there. + * + * This executes in the child context. */ static int ctdb_vacuum_db(struct ctdb_db_context *ctdb_db, struct vacuum_data *vdata, |