Add ability to cache negative results and specify negative TTL on templates

diff --git a/servers/slapd/overlays/pcache.c b/servers/slapd/overlays/pcache.c
index 5fdff0f7da5073b6c4bcbc9fb897a3e87a73d727..909457f4ef26e59bb8c8f3f81ae629396727fc8e 100644 (file)
--- a/servers/slapd/overlays/pcache.c
+++ b/servers/slapd/overlays/pcache.c
@@ -69,6 +69,7 @@ typedef struct query_template_s {
 
        int             no_of_queries;  /* Total number of queries in the template */
        time_t          ttl;            /* TTL for the queries of this template */
+       time_t          negttl;         /* TTL for negative results */
         ldap_pvt_thread_rdwr_t t_rwlock; /* Rd/wr lock for accessing queries in the template */
 } QueryTemplate;
 
@@ -90,7 +91,7 @@ struct query_manager_s;
 /* prototypes for functions for 1) query containment
  * 2) query addition, 3) cache replacement
  */
-typedef int    (QCfunc)(Operation *op, struct query_manager_s*, Query*, int );
+typedef CachedQuery *  (QCfunc)(Operation *op, struct query_manager_s*, Query*, int );
 typedef void   (AddQueryfunc)(struct query_manager_s*, Query*, int, struct berval*);
 typedef void   (CRfunc)(struct query_manager_s*, struct berval * );
 
@@ -473,7 +474,7 @@ final:
 /* check whether query is contained in any of
  * the cached queries in template template_index
  */
-static int
+static CachedQuery *
 query_containment(Operation *op, query_manager *qm,
                  Query *query,
                  int template_index)
@@ -526,7 +527,7 @@ query_containment(Operation *op, query_manager *qm,
                                                        Debug( LDAP_DEBUG_TRACE,
                                                        "Unlock: Exiting QC index=%d\n",
                                                        template_index, 0, 0 );
-                                                       return 0;
+                                                       return NULL;
                                                }
                                        }
                                        switch (fs->f_choice) {
@@ -590,7 +591,7 @@ query_containment(Operation *op, query_manager *qm,
                                                add_query_on_top(qm, qc);
                                        }
                                        ldap_pvt_thread_mutex_unlock(&qm->lru_mutex);
-                                       return 1;
+                                       return qc;
                                }
                        }
                }
@@ -599,7 +600,7 @@ query_containment(Operation *op, query_manager *qm,
                        template_index, 0, 0 );
                ldap_pvt_thread_rdwr_runlock(&(templa[template_index].t_rwlock));
        }
-       return 0;
+       return NULL;
 }
 
 static void
@@ -627,10 +628,15 @@ static void add_query(
        QueryTemplate* templ = (qm->templates)+template_index;
        Query* new_query;
        new_cached_query->template_id = template_index;
-       new_cached_query->q_uuid = *uuid;
+       if ( uuid ) {
+               new_cached_query->q_uuid = *uuid;
+               new_cached_query->expiry_time = slap_get_time() + templ->ttl;
+       } else {
+               BER_BVZERO( &new_cached_query->q_uuid );
+               new_cached_query->expiry_time = slap_get_time() + templ->negttl;
+       }
        new_cached_query->lru_up = NULL;
        new_cached_query->lru_down = NULL;
-       new_cached_query->expiry_time = slap_get_time() + templ->ttl;
        Debug( LDAP_DEBUG_TRACE, "Added query expires at %ld\n",
                        (long) new_cached_query->expiry_time, 0, 0 );
        new_query = (Query*)new_cached_query;
@@ -1018,11 +1024,6 @@ cache_entries(
                return_val = 0;
                ldap_pvt_thread_mutex_unlock(&cm->cache_mutex);
        }
-       ldap_pvt_thread_mutex_lock(&cm->cache_mutex);
-       cm->num_cached_queries++;
-       Debug( LDAP_DEBUG_TRACE, "STORED QUERIES = %lu\n",
-                       cm->num_cached_queries, 0, 0 );
-       ldap_pvt_thread_mutex_unlock(&cm->cache_mutex);
 
        return return_val;
 }
@@ -1038,6 +1039,12 @@ pcache_response(
        query_manager*          qm = cm->qm;
        struct berval uuid;
 
+       if ( si->query.save_attrs != NULL ) {
+               rs->sr_attrs = si->query.save_attrs;
+               op->ors_attrs = si->query.save_attrs;
+               si->query.save_attrs = NULL;
+       }
+
        if ( rs->sr_type == REP_SEARCH ) {
                Entry *e;
                /* If we haven't exceeded the limit for this query,
@@ -1062,15 +1069,20 @@ pcache_response(
                                si->tail = NULL;
                        }
                }
-               if ( si->query.save_attrs != NULL ) {
-                       rs->sr_attrs = si->query.save_attrs;
-                       op->ors_attrs = si->query.save_attrs;
-                       si->query.save_attrs = NULL;
-               }
 
        } else if ( rs->sr_type == REP_RESULT ) {
-               if ( si->count && cache_entries( op, rs, &uuid ) == 0 ) {
-                       qm->addfunc(qm, &si->query, si->template_id, &uuid);
+               QueryTemplate* templ = (qm->templates)+si->template_id;
+               if (( si->count && cache_entries( op, rs, &uuid ) == 0 ) ||
+                       ( !si->count && templ->negttl )) {
+                       qm->addfunc(qm, &si->query, si->template_id,
+                               si->count ? &uuid : NULL);
+
+                       ldap_pvt_thread_mutex_lock(&cm->cache_mutex);
+                       cm->num_cached_queries++;
+                       Debug( LDAP_DEBUG_TRACE, "STORED QUERIES = %lu\n",
+                                       cm->num_cached_queries, 0, 0 );
+                       ldap_pvt_thread_mutex_unlock(&cm->cache_mutex);
+
                        /* If the consistency checker suspended itself,
                         * wake it back up
                         */
@@ -1205,7 +1217,7 @@ pcache_op_search(
 
        int             attr_set = -1;
        int             template_id = -1;
-       int             answerable = 0;
+       CachedQuery     *answerable = NULL;
        int             cacheable = 0;
        int             fattr_cnt=0;
        int             fattr_got_oc = 0;
@@ -1269,9 +1281,15 @@ pcache_op_search(
                Debug( LDAP_DEBUG_TRACE, "QUERY ANSWERABLE\n", 0, 0, 0 );
                op->o_tmpfree( filter_attrs, op->o_tmpmemctx );
                ldap_pvt_thread_rdwr_runlock(&qm->templates[i].t_rwlock);
-               op->o_bd = &cm->db;
-               op->o_callback = NULL;
-               i = cm->db.bd_info->bi_op_search( op, rs );
+               if ( BER_BVISNULL( &answerable->q_uuid )) {
+                       /* No entries cached, just an empty result set */
+                       i = rs->sr_err = 0;
+                       send_ldap_result( op, rs );
+               } else {
+                       op->o_bd = &cm->db;
+                       op->o_callback = NULL;
+                       i = cm->db.bd_info->bi_op_search( op, rs );
+               }
                op->o_bd = save_bd;
                op->o_callback = save_cb;
                return i;
@@ -1419,7 +1437,10 @@ consistency_check(
                        Debug( LDAP_DEBUG_TRACE, "Unlock CR index = %d\n",
                                        i, 0, 0 );
                        ldap_pvt_thread_rdwr_wunlock(&templ->t_rwlock);
-                       return_val = remove_query_data(op, &rs, &query->q_uuid);
+                       if ( BER_BVISNULL( &query->q_uuid ))
+                               return_val = 0;
+                       else
+                               return_val = remove_query_data(op, &rs, &query->q_uuid);
                        Debug( LDAP_DEBUG_TRACE, "STALE QUERY REMOVED, SIZE=%d\n",
                                                return_val, 0, 0 );
                        ldap_pvt_thread_mutex_lock(&cm->cache_mutex);
@@ -1477,10 +1498,10 @@ static ConfigTable pccfg[] = {
                "( OLcfgOvAt:2.2 NAME 'olcProxyAttrset' "
                        "DESC 'A set of attributes to cache' "
                        "SYNTAX OMsDirectoryString )", NULL, NULL },
-       { "proxytemplate", "filter> <attrset-index> <TTL",
-               4, 4, 0, ARG_MAGIC|PC_TEMP, pc_cf_gen,
+       { "proxytemplate", "filter> <attrset-index> <TTL> <negTTL",
+               4, 5, 0, ARG_MAGIC|PC_TEMP, pc_cf_gen,
                "( OLcfgOvAt:2.3 NAME 'olcProxyTemplate' "
-                       "DESC 'Filter template, attrset, and cache TTL' "
+                       "DESC 'Filter template, attrset, cache TTL, optional negative TTL' "
                        "SYNTAX OMsDirectoryString )", NULL, NULL },
        { "response-callback", "head|tail(default)",
                2, 2, 0, ARG_MAGIC|PC_RESP, pc_cf_gen,
@@ -1597,9 +1618,17 @@ pc_cf_gen( ConfigArgs *c )
                        break;
                case PC_TEMP:
                        for (i=0; i<cm->numtemplates; i++) {
-                               bv.bv_len = snprintf( c->msg, sizeof( c->msg ), " %d %ld",
-                                       qm->templates[i].attr_set_index,
-                                       qm->templates[i].ttl );
+                               if ( qm->templates[i].negttl ) {
+                                       bv.bv_len = snprintf( c->msg, sizeof( c->msg ),
+                                               " %d %ld %ld",
+                                               qm->templates[i].attr_set_index,
+                                               qm->templates[i].ttl,
+                                               qm->templates[i].negttl );
+                               } else {
+                                       bv.bv_len = snprintf( c->msg, sizeof( c->msg ), " %d %ld",
+                                               qm->templates[i].attr_set_index,
+                                               qm->templates[i].ttl );
+                               }
                                bv.bv_len += qm->templates[i].querystr.bv_len + 2;
                                bv.bv_val = ch_malloc( bv.bv_len+1 );
                                ptr = bv.bv_val;
@@ -1788,6 +1817,18 @@ pc_cf_gen( ConfigArgs *c )
                        return( 1 );
                }
                temp->ttl = (time_t)t;
+               if ( c->argc == 5 ) {
+                       if ( lutil_parse_time( c->argv[4], &t ) != 0 ) {
+                               snprintf( c->msg, sizeof( c->msg ),
+                                       "unable to parse template negttl=\"%s\"",
+                                       c->argv[4] );
+                               Debug( LDAP_DEBUG_CONFIG, "%s: %s.\n", c->log, c->msg, 0 );
+                                       return( 1 );
+                       }
+                       temp->negttl = (time_t)t;
+               } else {
+                       temp->negttl = 0;
+               }
 
                temp->no_of_queries = 0;