Fix for flush_all 1-second window bug. You can now do a "set" immedia…

…tely

after a "flush_all" without the newly set data getting expired.


git-svn-id: http://code.sixapart.com/svn/memcached/trunk/server@436 b0b603af-a30f-0410-a34e-baf09ae79d0b

items.c

@@ -320,3 +320,29 @@ char* item_stats_sizes(int *bytes) {
     free(histogram);
     return buf;
 }
+
+/* expires items that are more recent than the oldest_live setting. */
+void item_flush_expired() {
+    int i;
+    item *iter, *next;
+    if (! settings.oldest_live)
+        return;
+    for (i = 0; i < LARGEST_ID; i++) {
+        /* The LRU is sorted in decreasing time order, and an item's timestamp
+         * is never newer than its last access time, so we only need to walk
+         * back until we hit an item older than the oldest_live time.
+         * The oldest_live checking will auto-expire the remaining items.
+         */
+        for (iter = heads[i]; iter != NULL; iter = next) {
+            if (iter->time >= settings.oldest_live) {
+                next = iter->next;
+                if ((iter->it_flags & ITEM_SLABBED) == 0) {
+                    item_unlink(iter);
+                }
+            } else {
+                /* We've hit the first old item. Continue to the next queue. */
+                break;
+            }
+        }
+    }
+}

memcached.c

@@ -95,11 +95,11 @@ void stats_init(void) {
     stats.get_cmds = stats.set_cmds = stats.get_hits = stats.get_misses = 0;
     stats.curr_bytes = stats.bytes_read = stats.bytes_written = 0;
 
-    /* make the time we started always be 1 second before we really
+    /* make the time we started always be 2 seconds before we really
        did, so time(0) - time.started is never zero.  if so, things
        like 'settings.oldest_live' which act as booleans as well as
        values are now false in boolean context... */
-    stats.started = time(0) - 1;
+    stats.started = time(0) - 2;
 }
 void stats_reset(void) {
     stats.total_items = stats.total_conns = 0;
@@ -1155,7 +1155,8 @@ void process_command(conn *c, char *command) {
         set_current_time();
 
         if (strcmp(command, "flush_all") == 0) {
-            settings.oldest_live = current_time;
+            settings.oldest_live = current_time - 1;
+            item_flush_expired();
             out_string(c, "OK");
             return;
         }
@@ -1166,7 +1167,8 @@ void process_command(conn *c, char *command) {
             return;
         }
 
-        settings.oldest_live = realtime(exptime);
+        settings.oldest_live = realtime(exptime) - 1;
+        item_flush_expired();
         out_string(c, "OK");
         return;
     }

memcached.h

@@ -271,6 +271,7 @@ int item_replace(item *it, item *new_it);
 char *item_cachedump(unsigned int slabs_clsid, unsigned int limit, unsigned int *bytes);
 char *item_stats_sizes(int *bytes);
 void item_stats(char *buffer, int buflen);
+void item_flush_expired(void);
 
 /* time handling */
 void set_current_time ();  /* update the global variable holding

t/flush-all.t

@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
-use Test::More tests => 11;
+use Test::More tests => 10;
 use FindBin qw($Bin);
 use lib "$Bin/lib";
 use MemcachedTest;
@@ -16,18 +16,12 @@ is(scalar <$sock>, "STORED\r\n", "stored foo");
 mem_get_is($sock, "foo", "fooval");
 print $sock "flush_all\r\n";
 is(scalar <$sock>, "OK\r\n", "did flush_all");
-
 mem_get_is($sock, "foo", undef);
-SKIP: {
-    skip "flush_all is still only second-granularity.  need atomic counter on flush_all.", 2 unless 0;
-
-    print $sock "set foo 0 0 3\r\nnew\r\n";
-    is(scalar <$sock>, "STORED\r\n", "stored foo = 'new'");
-    mem_get_is($sock, "foo", 'new');
-}
 
-sleep 1;
-mem_get_is($sock, "foo", undef);
+# check that flush_all doesn't blow away items that immediately get set
+print $sock "set foo 0 0 3\r\nnew\r\n";
+is(scalar <$sock>, "STORED\r\n", "stored foo = 'new'");
+mem_get_is($sock, "foo", 'new');
 
 # and the other form, specifying a flush_all time...
 my $expire = time() + 2;