merge

sql/ha_berkeley.cc

@@ -25,8 +25,9 @@
     We will need an updated Berkeley DB version for this.
   - Killing threads that has got a 'deadlock'
   - SHOW TABLE STATUS should give more information about the table.
-  - Get a more accurate count of the number of rows.
-    We could store the found number of rows when the table is scanned.
+  - Get a more accurate count of the number of rows (estimate_number_of_rows()).
+    We could store the found number of rows when the table is scanned and
+    then increment the counter for each attempted write.
   - We will need a manager thread that calls flush_logs, removes old
     logs and makes checkpoints at given intervals.
   - When not using UPDATE IGNORE, don't make a sub transaction but abort
@@ -42,7 +43,6 @@
   - LOCK TABLES
   - CHAR keys
   - BLOBS
-  - delete from t1;
 */
 
 
@@ -60,6 +60,7 @@
 
 #define HA_BERKELEY_ROWS_IN_TABLE 10000 /* to get optimization right */
 #define HA_BERKELEY_RANGE_COUNT	  100
+#define HA_BERKELEY_MAX_ROWS	  10000000 /* Max rows in table */
 
 const char *ha_berkeley_ext=".db";
 bool berkeley_skip=0;
@@ -1297,7 +1298,7 @@ void ha_berkeley::info(uint flag)
   DBUG_ENTER("info");
   if (flag & HA_STATUS_VARIABLE)
   {
-    records = HA_BERKELEY_ROWS_IN_TABLE; // Just to get optimisations right
+    records = estimate_number_of_rows(); 		// Just to get optimisations right
     deleted = 0;
   }
   else if (flag & HA_STATUS_ERRKEY)
@@ -1607,4 +1608,21 @@ void ha_berkeley::update_auto_primary_key()
   pthread_mutex_unlock(&share->mutex);
 }
 
+/*
+  Return an estimated of the number of rows in the table.
+  Used when sorting to allocate buffers and by the optimizer.
+*/
+
+ha_rows ha_berkeley::estimate_number_of_rows()
+{
+  ulonglong max_ident;
+  ulonglong max_rows=table->max_rows ? table->max_rows : HA_BERKELEY_MAX_ROWS;
+  if (!hidden_primary_key)
+    return (ha_rows) max_rows;
+  pthread_mutex_lock(&share->mutex);
+  max_ident=share->auto_ident+EXTRA_RECORDS;
+  pthread_mutex_unlock(&share->mutex);
+  return (ha_rows) min(max_ident,max_rows);
+}
+
 #endif /* HAVE_BERKELEY_DB */