dsdb-schema: do not reload more often than schema_reload_interval

[metze/samba/wip.git] / source4 / dsdb / samdb / ldb_modules / schema_load.c

diff --git a/source4/dsdb/samdb/ldb_modules/schema_load.c b/source4/dsdb/samdb/ldb_modules/schema_load.c
index 4c166d51ce5f76d0bab2b2fd16ce3cc6822a7321..f922aabba90e2e96c02b5245e56bf505fcd7e935 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/schema_load.c
+++ b/source4/dsdb/samdb/ldb_modules/schema_load.c
@@ -49,6 +49,10 @@ static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct
        struct dsdb_control_current_partition *ctrl;
        struct ldb_context *ldb = ldb_module_get_ctx(module);
        struct dsdb_schema *new_schema;
+       int interval;
+       time_t ts, lastts;
+       struct loadparm_context *lp_ctx =
+               (struct loadparm_context *)ldb_get_opaque(ldb, "loadparm");
        
        struct schema_load_private_data *private_data = talloc_get_type(ldb_module_get_private(module), struct schema_load_private_data);
        if (!private_data) {
@@ -61,6 +65,14 @@ static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct
                return schema;
        }
 
+       lastts = schema->last_refresh;
+       ts = time(NULL);
+       interval = lpcfg_parm_int(lp_ctx, NULL, "dsdb", "schema_reload_interval", 120);
+       if (lastts > (ts - interval)) {
+               DEBUG(11, ("Less than %d seconds since last reload, returning cached version ts = %d\n", interval, (int)lastts));
+               return schema;
+       }
+
        res = talloc_zero(schema, struct ldb_result);
        if (res == NULL) {
                return NULL;
@@ -84,7 +96,16 @@ static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct
                talloc_free(res);
                return NULL;
        }
-       
+
+       /*
+        * We update right now the last refresh timestamp so that if
+        * the schema partition hasn't change we don't keep on retrying.
+        * Otherwise if the timestamp was update only when the schema has
+        * actually changed (and therefor completely reloaded) we would
+        * continue to hit the database to get the highest USN.
+        */
+       schema->last_refresh = ts;
+
        ctrl = talloc(treq, struct dsdb_control_current_partition);
        if (!ctrl) {
                talloc_free(res);
@@ -130,7 +151,7 @@ static struct dsdb_schema *dsdb_schema_refresh(struct ldb_module *module, struct
        if (ret != LDB_SUCCESS) {
                return schema;
        }
-       
+
        if (is_global_schema) {
                dsdb_make_schema_global(ldb, new_schema);
        }
@@ -226,6 +247,7 @@ static int dsdb_schema_from_db(struct ldb_module *module, struct ldb_dn *schema_
        ret = dsdb_set_schema(ldb, (*schema));
 
        (*schema)->refresh_in_progress = false;
+       (*schema)->last_refresh = time(NULL);
 
        if (ret != LDB_SUCCESS) {
                ldb_debug_set(ldb, LDB_DEBUG_FATAL,
@@ -324,9 +346,22 @@ static int schema_load_del_transaction(struct ldb_module *module)
 
 static int schema_load_extended(struct ldb_module *module, struct ldb_request *req)
 {
+       time_t *lastts;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct dsdb_schema *schema;
+
        if (strcmp(req->op.extended.oid, DSDB_EXTENDED_SCHEMA_UPDATE_NOW_OID) != 0) {
                return ldb_next_request(module, req);
        }
+       lastts = (time_t *)ldb_get_opaque(ldb, DSDB_OPAQUE_LAST_SCHEMA_UPDATE_MSG_OPAQUE_NAME);
+       if (!lastts) {
+               lastts = talloc(ldb, time_t);
+       }
+       schema = dsdb_get_schema(ldb, NULL);
+       /* Force a refresh */
+       schema->last_refresh = 0;
+       *lastts = 0;
+       ldb_set_opaque(ldb, DSDB_OPAQUE_LAST_SCHEMA_UPDATE_MSG_OPAQUE_NAME, lastts);
 
        /* This is a no-op.  We reload as soon as we can */
        return ldb_module_done(req, NULL, NULL, LDB_SUCCESS);