Keep mailbox indexes cached for a while after they've been closed. Should

speed up at least multiple APPENDs.

--HG--
branch : HEAD

diff --git a/src/lib-storage/index/index-storage.c b/src/lib-storage/index/index-storage.c
index 9a252d436f69d4c774c0764967d7a3ff1f16a307..1b42c6745688446f9d48e6ad18ab0f83f720bb18 100644 (file)
--- a/src/lib-storage/index/index-storage.c
+++ b/src/lib-storage/index/index-storage.c
@@ -1,6 +1,7 @@
 /* Copyright (C) 2002 Timo Sirainen */
 
 #include "lib.h"
+#include "ioloop.h"
 #include "mail-index.h"
 #include "mail-index-util.h"
 #include "mail-custom-flags.h"
@@ -11,6 +12,11 @@
 #include <unistd.h>
 #include <sys/stat.h>
 
+/* How many seconds to keep index opened for reuse after it's been closed */
+#define INDEX_CACHE_TIMEOUT 10
+/* How many closed indexes to keep */
+#define INDEX_CACHE_MAX 3
+
 #define LOCK_NOTIFY_INTERVAL 30
 
 struct index_list {
@@ -18,6 +24,8 @@ struct index_list {
 
        struct mail_index *index;
        int refcount;
+
+       time_t destroy_time;
 };
 
 static struct index_list *indexes = NULL;
@@ -36,39 +44,54 @@ void index_storage_add(struct mail_index *index)
 
 struct mail_index *index_storage_lookup_ref(const char *path)
 {
-       struct index_list *list;
+       struct index_list **list, *rec;
+       struct mail_index *match;
        struct stat st1, st2;
+       int destroy_count;
 
        if (stat(path, &st1) < 0)
                return NULL;
 
        /* compare inodes so we don't break even with symlinks */
-       for (list = indexes; list != NULL; list = list->next) {
-               if (stat(list->index->dir, &st2) == 0) {
+       destroy_count = 0; match = NULL;
+       for (list = &indexes; *list != NULL;) {
+               rec = *list;
+
+               if (stat(rec->index->dir, &st2) == 0) {
                        if (st1.st_ino == st2.st_ino &&
                            st1.st_dev == st2.st_dev) {
-                               list->refcount++;
-                               return list->index;
+                               rec->refcount++;
+                               match = rec->index;
+                       }
+               }
+
+               if (rec->refcount == 0) {
+                       if (rec->destroy_time <= ioloop_time ||
+                           destroy_count >= INDEX_CACHE_MAX) {
+                               rec->index->free(rec->index);
+                               *list = rec->next;
+                               i_free(rec);
+                               continue;
+                       } else {
+                               destroy_count++;
                        }
                }
+
+                list = &(*list)->next;
        }
 
-       return NULL;
+       return match;
 }
 
 void index_storage_unref(struct mail_index *index)
 {
-       struct index_list **list, *rec;
-
-       for (list = &indexes; *list != NULL; list = &(*list)->next) {
-               rec = *list;
+       struct index_list *list;
 
-               if (rec->index == index) {
-                       if (--rec->refcount == 0) {
-                               index->free(index);
-                               *list = rec->next;
-                               i_free(rec);
-                       }
+       for (list = indexes; list != NULL; list = list->next) {
+               if (list->index == index) {
+                       i_assert(list->refcount > 0);
+                       list->refcount--;
+                       list->destroy_time = ioloop_time + INDEX_CACHE_TIMEOUT;
                        return;
                }
        }