From 87e9791ee9a652b3665d59ca5bf0e927e935e666 Mon Sep 17 00:00:00 2001
From: Adam Dickmeiss <adam@indexdata.dk>
Date: Mon, 4 Feb 2013 14:21:13 +0100
Subject: [PATCH] Revise extended fetch algorithm

If the show records returned were the last in the sorted "window" of
records per-client , an extended fetch will be attempted. Only if there
are more records to be fetched (hit count depending) and pz:extendrecs
is defined, another fetch will be initiated.
---
 src/client.c  |   19 +++++++++++++++++++
 src/client.h  |    1 +
 src/session.c |   56 ++++++++++++++++++++++++++++++++++----------------------
 3 files changed, 54 insertions(+), 22 deletions(-)

diff --git a/src/client.c b/src/client.c
index 4c40d9c..39140a7 100644
--- a/src/client.c
+++ b/src/client.c
@@ -115,6 +115,7 @@ struct client {
     char *addinfo; // diagnostic info for most resent error
     Odr_int hits;
     int record_offset;
+    int show_stat_no;
     int filtered; // When using local:, this will count the number of filtered records.
     int maxrecs;
     int startrecs;
@@ -762,6 +763,14 @@ static const char *get_strategy_plus_sort(struct client *l, const char *field)
     return strategy_plus_sort;
 }
 
+void client_update_show_stat(struct client *cl, int cmd)
+{
+    if (cmd == 0)
+        cl->show_stat_no = 0;
+    else if (cmd == 1)
+        cl->show_stat_no++;
+}
+
 int client_fetch_more(struct client *cl)
 {
     struct session_database *sdb = client_get_database(cl);
@@ -769,6 +778,12 @@ int client_fetch_more(struct client *cl)
     int extend_recs = 0;
     int number;
 
+    yaz_log(YLOG_LOG, "cl=%s show_stat_no=%d got=%d",
+            client_get_id(cl), cl->show_stat_no, cl->record_offset);
+    if (cl->show_stat_no < cl->record_offset)
+        return 0;
+    yaz_log(YLOG_LOG, "cl=%s Trying to get more", client_get_id(cl));
+
     str = session_setting_oneval(sdb, PZ_EXTENDRECS);
     if (str && *str)
         extend_recs = atoi(str);
@@ -793,6 +808,10 @@ int client_fetch_more(struct client *cl)
         connection_continue(co);
         return 1;
     }
+    else
+    {
+        yaz_log(YLOG_LOG, "cl=%s. OK no more in total set", client_get_id(cl));
+    }
     return 0;
 }
 
diff --git a/src/client.h b/src/client.h
index eeccf0f..483136b 100644
--- a/src/client.h
+++ b/src/client.h
@@ -117,6 +117,7 @@ const char *client_get_facet_limit_local(struct client *cl,
                                          NMEM nmem, int *num, char ***values);
 
 int client_test_sort_order(struct client *cl, struct reclist_sortparms *sp);
+void client_update_show_stat(struct client *cl, int cmd);
 
 #endif
 
diff --git a/src/session.c b/src/session.c
index 41bcb30..e81c221 100644
--- a/src/session.c
+++ b/src/session.c
@@ -1271,7 +1271,6 @@ struct record_cluster **show_range_start(struct session *se,
     struct record_cluster **recs = 0;
     struct reclist_sortparms *spp;
     struct client_list *l;
-    int num0 = *num;
     int i;
 #if USE_TIMING
     yaz_timing_t t = yaz_timing_create();
@@ -1299,13 +1298,24 @@ struct record_cluster **show_range_start(struct session *se,
     reclist_enter(se->reclist);
     *total = reclist_get_num_records(se->reclist);
 
+    for (l = se->clients_active; l; l = l->next)
+        client_update_show_stat(l->client, 0);
+
     for (i = 0; i < start; i++)
-        if (!reclist_read_record(se->reclist))
+    {
+        struct record_cluster *r = reclist_read_record(se->reclist);
+        if (!r)
         {
             *num = 0;
             break;
         }
-
+        else
+        {
+            struct record *rec = r->records;
+            for (;rec; rec = rec->next)
+                client_update_show_stat(rec->client, 1);
+        }
+    }
     if (*num > 0)
         recs =
             nmem_malloc(se->nmem, *num * sizeof(struct record_cluster *));
@@ -1317,7 +1327,13 @@ struct record_cluster **show_range_start(struct session *se,
             *num = i;
             break;
         }
-        recs[i] = r;
+        else
+        {
+            struct record *rec = r->records;
+            for (;rec; rec = rec->next)
+                client_update_show_stat(rec->client, 1);
+            recs[i] = r;
+        }
     }
     reclist_leave(se->reclist);
 #if USE_TIMING
@@ -1327,27 +1343,23 @@ struct record_cluster **show_range_start(struct session *se,
             yaz_timing_get_sys(t));
     yaz_timing_destroy(&t);
 #endif
-    if (*num < num0)
+
+    if (!session_fetch_more(se))
+        session_log(se, YLOG_LOG, "can not fetch more");
+    else
     {
-        session_log(se, YLOG_LOG,
-                    "Subset %d < %d retrieved for show", *num, num0);
-        if (!session_fetch_more(se))
-            session_log(se, YLOG_LOG, "can not fetch more");
+        show_range_stop(se, recs);
+        session_log(se, YLOG_LOG, "fetching more in progress");
+        if (session_set_watch(se, SESSION_WATCH_SHOW,
+                              show_records_ready, chan, chan))
+        {
+            session_log(se, YLOG_WARN, "Ignoring show block");
+            session_enter(se, "show_range_start");
+        }
         else
         {
-            show_range_stop(se, recs);
-            session_log(se, YLOG_LOG, "fetching more in progress");
-            if (session_set_watch(se, SESSION_WATCH_SHOW,
-                                  show_records_ready, chan, chan))
-            {
-                session_log(se, YLOG_WARN, "Ignoring show block");
-                session_enter(se, "show_range_start");
-            }
-            else
-            {
-                session_log(se, YLOG_LOG, "session watch OK");
-                return 0;
-            }
+            session_log(se, YLOG_LOG, "session watch OK");
+            return 0;
         }
     }
     return recs;
-- 
1.7.10.4