replmd: Cache recycle-bin state to avoid DB lookup

By caching the recycle-bin state we can save ~6% of the join time.

Checking whether the recycle-bin is enabled involves an underlying DSDB
search. We do this ~4 times for each link we replicate (twice for the
link source and target). By caching the recycle-bin's state over the
duration of the replication, we can save 1000s of unnecessary DB
searches.

With 5K users this makes the join time ~5 secs faster.

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Tim Beale <timbeale@samba.org>
Autobuild-Date(master): Tue Nov 20 08:40:16 CET 2018 on sn-devel-144

diff --git a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
index fb1f6f5d847765e2a1078852b00ecf83dfd1545c..58f9df9c98cf03fe401f49dc61d63ccd2eefbc46 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
+++ b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
@@ -77,6 +77,8 @@ struct replmd_private {
        bool sorted_links;
        uint32_t total_links;
        uint32_t num_processed;
+       bool recyclebin_enabled;
+       bool recyclebin_state_known;
 };
 
 /*
@@ -174,12 +176,35 @@ enum deletion_state {
        OBJECT_REMOVED=5
 };
 
+static bool replmd_recyclebin_enabled(struct ldb_module *module)
+{
+       bool enabled = false;
+       struct replmd_private *replmd_private =
+               talloc_get_type_abort(ldb_module_get_private(module),
+                                     struct replmd_private);
+
+       /*
+        * only lookup the recycle-bin state once per replication, then cache
+        * the result. This can save us 1000s of DB searches
+        */
+       if (!replmd_private->recyclebin_state_known) {
+               int ret = dsdb_recyclebin_enabled(module, &enabled);
+               if (ret != LDB_SUCCESS) {
+                       return false;
+               }
+
+               replmd_private->recyclebin_enabled = enabled;
+               replmd_private->recyclebin_state_known = true;
+       }
+
+       return replmd_private->recyclebin_enabled;
+}
+
 static void replmd_deletion_state(struct ldb_module *module,
                                  const struct ldb_message *msg,
                                  enum deletion_state *current_state,
                                  enum deletion_state *next_state)
 {
-       int ret;
        bool enabled = false;
 
        if (msg == NULL) {
@@ -190,10 +215,7 @@ static void replmd_deletion_state(struct ldb_module *module,
                return;
        }
 
-       ret = dsdb_recyclebin_enabled(module, &enabled);
-       if (ret != LDB_SUCCESS) {
-               enabled = false;
-       }
+       enabled = replmd_recyclebin_enabled(module);
 
        if (ldb_msg_check_string_attribute(msg, "isDeleted", "TRUE")) {
                if (!enabled) {
@@ -334,7 +356,7 @@ static void replmd_txn_cleanup(struct replmd_private *replmd_private)
        talloc_free(replmd_private->la_ctx);
        replmd_private->la_list = NULL;
        replmd_private->la_ctx = NULL;
-
+       replmd_private->recyclebin_state_known = false;
 }