New setting setting: pz:max_connections

Setting pz:max_connections is a limit of number of sockets to a host.
When this limit is reached, Pazpar2 will wait up to 5 seconds for a
connection to becomes available. The client will be marked Client_Error
when it can not be searched (other clients in a session may work).
If pz:max_connections is not set for a target, a value of 30 will be
used.

diff --git a/src/client.h b/src/client.h
index 4f39ebb..4d23481 100644 (file)
--- a/src/client.h
+++ b/src/client.h
@@ -72,7 +72,8 @@ void client_set_connection(struct client *cl, struct connection *con);
 void client_disconnect(struct client *cl);
 int client_prep_connection(struct client *cl,
                            int operation_timeout, int session_timeout,
-                           iochan_man_t iochan);
+                           iochan_man_t iochan,
+                           const struct timespec *abstime);
 void client_start_search(struct client *cl);
 void client_set_session(struct client *cl, struct session *se);
 int client_is_active(struct client *cl);

diff --git a/src/connection.c b/src/connection.c
index da7c1a5..f95beb1 100644 (file)
--- a/src/connection.c
+++ b/src/connection.c
@@ -122,6 +122,7 @@ static void remove_connection_from_host(struct connection *con)
         }
         conp = &(*conp)->next;
     }
+    yaz_cond_broadcast(con->host->cond_ready);
 }
 
 // Close connection and recycle structure
@@ -210,6 +211,7 @@ static void non_block_events(struct connection *co)
                 iochan_settimeout(iochan, co->session_timeout);
                client_set_diagnostic(cl, err);
                 client_set_state(cl, Client_Idle);
+                yaz_cond_broadcast(co->host->cond_ready);
             }
             break;
         case ZOOM_EVENT_SEND_DATA:
@@ -448,7 +450,8 @@ static int connection_connect(struct connection *con, iochan_man_t iochan_man)
 // Ensure that client has a connection associated
 int client_prep_connection(struct client *cl,
                            int operation_timeout, int session_timeout,
-                           iochan_man_t iochan_man)
+                           iochan_man_t iochan_man,
+                           const struct timespec *abstime)
 {
     struct connection *co;
     struct host *host = client_get_host(cl);
@@ -467,21 +470,56 @@ int client_prep_connection(struct client *cl,
 
     if (!co)
     {
+        int max_connections = 30;
+        const char *v = session_setting_oneval(client_get_database(cl),
+                                               PZ_MAX_CONNECTIONS);
+        if (v && *v)
+            max_connections = atoi(v);
+        
         // See if someone else has an idle connection
         // We should look at timestamps here to select the longest-idle connection
         yaz_mutex_enter(host->mutex);
-        for (co = host->connections; co; co = co->next)
-            if (connection_is_idle(co) &&
-                (!co->client || client_get_state(co->client) == Client_Idle) &&
-                !strcmp(ZOOM_connection_option_get(co->link, "user"),
-                        session_setting_oneval(client_get_database(cl),
-                                               PZ_AUTHENTICATION)))
+        while (1)
+        {
+            int num_connections = 0;
+            for (co = host->connections; co; co = co->next)
+                num_connections++;
+            for (co = host->connections; co; co = co->next)
+            {
+                if (connection_is_idle(co) &&
+                    (!co->client || client_get_state(co->client) == Client_Idle) &&
+                    !strcmp(ZOOM_connection_option_get(co->link, "user"),
+                            session_setting_oneval(client_get_database(cl),
+                                                   PZ_AUTHENTICATION)))
+                {
+                    if (zproxy == 0 && co->zproxy == 0)
+                        break;
+                    if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
+                        break;
+                }
+            }
+            if (co)
             {
-                if (zproxy == 0 && co->zproxy == 0)
-                    break;
-                if (zproxy && co->zproxy && !strcmp(zproxy, co->zproxy))
-                    break;
+                yaz_log(YLOG_LOG, "num_connections = %d (reusing)",
+                        num_connections);
+                break;
             }
+            if (num_connections < max_connections)
+            {
+                yaz_log(YLOG_LOG, "num_connections = %d (new); max = %d",
+                        num_connections, max_connections);
+                break;
+            }
+            yaz_log(YLOG_LOG, "num_connections = %d (waiting) max = %d",
+                    num_connections, max_connections);
+            if (yaz_cond_wait(host->cond_ready, host->mutex, abstime))
+            {
+                yaz_log(YLOG_LOG, "out of connections %s", client_get_url(cl));
+                client_set_state(cl, Client_Error);
+                yaz_mutex_leave(host->mutex);
+                return 0;
+            }
+        }
         if (co)
         {
             connection_release(co);

diff --git a/src/database.c b/src/database.c
index ab425c7..da26ed0 100644 (file)
--- a/src/database.c
+++ b/src/database.c
@@ -112,6 +112,8 @@ static struct host *create_host(const char *hostport, iochan_man_t iochan_man)
     }
     pazpar2_mutex_create(&host->mutex, "host");
 
+    yaz_cond_create(&host->cond_ready);
+
     return host;
 }
 
@@ -185,7 +187,7 @@ struct database *new_database(const char *id, NMEM nmem)
     db->errors = 0;
     db->explain = 0;
 
-    db->num_settings = PZ_NEGOTIATION_CHARSET+1;
+    db->num_settings = PZ_MAX_EOF;
     db->settings = nmem_malloc(nmem, sizeof(struct settings*) * 
                                db->num_settings);
     memset(db->settings, 0, sizeof(struct settings*) * db->num_settings);
@@ -424,6 +426,7 @@ void database_hosts_destroy(database_hosts_t *pp)
         {
             struct host *p_next = p->next;
             yaz_mutex_destroy(&p->mutex);
+            yaz_cond_destroy(&p->cond_ready);
             xfree(p->ipport);
             xfree(p->hostport);
             xfree(p);

diff --git a/src/host.h b/src/host.h
index 49f0107..5409f73 100644 (file)
--- a/src/host.h
+++ b/src/host.h
@@ -29,6 +29,7 @@ struct host {
     struct connection *connections; // All connections to this
     struct host *next;
     YAZ_MUTEX mutex;
+    YAZ_COND cond_ready;
 };
 
 

diff --git a/src/session.c b/src/session.c
index 6327ba9..14b9a2c 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -25,6 +25,7 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #include <config.h>
 #endif
 
+#include <time.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -513,6 +514,8 @@ enum pazpar2_error_code search(struct session *se,
     int no_working = 0;
     int no_failed = 0;
     struct client_list *l;
+    struct timespec abstime;
+    struct timeval tval;
 
     yaz_log(YLOG_DEBUG, "Search");
 
@@ -535,6 +538,11 @@ enum pazpar2_error_code search(struct session *se,
     }
     se->reclist = reclist_create(se->nmem);
 
+    gettimeofday(&tval, 0);
+    
+    abstime.tv_sec = tval.tv_sec + 5;
+    abstime.tv_nsec = tval.tv_usec * 1000;
+
     for (l = se->clients; l; l = l->next)
     {
         struct client *cl = l->client;
@@ -552,7 +560,8 @@ enum pazpar2_error_code search(struct session *se,
             no_working++;
             if (client_prep_connection(cl, se->service->z3950_operation_timeout,
                                        se->service->z3950_session_timeout,
-                                       se->service->server->iochan_man))
+                                       se->service->server->iochan_man,
+                                       &abstime))
                 client_start_search(cl);
         }
     }

diff --git a/src/settings.c b/src/settings.c
index 2d99c78..5308eef 100644 (file)
--- a/src/settings.c
+++ b/src/settings.c
@@ -69,6 +69,7 @@ static char *hard_settings[] = {
     "pz:recordfilter",
     "pz:pqf_strftime",
     "pz:negotiation_charset",
+    "pz:max_connections",
     0
 };
 

diff --git a/src/settings.h b/src/settings.h
index 43d162e..71fb326 100644 (file)
--- a/src/settings.h
+++ b/src/settings.h
@@ -42,6 +42,8 @@ Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 #define PZ_RECORDFILTER         19
 #define PZ_PQF_STRFTIME  20
 #define PZ_NEGOTIATION_CHARSET  21
+#define PZ_MAX_CONNECTIONS 22
+#define PZ_MAX_EOF       23
 
 struct setting
 {