Corrected fragmentation calculation to take into account that LQH creates "2...

Corrected fragmentation calculation to take into account that LQH creates "2 fragments per fragment" in 4.1 and 5.0
+added some comments to ndb fragmentation calulation
parent b97a519d
...@@ -3513,18 +3513,23 @@ static void ndb_set_fragmentation(NDBTAB &tab, TABLE *form, uint pk_length) ...@@ -3513,18 +3513,23 @@ static void ndb_set_fragmentation(NDBTAB &tab, TABLE *form, uint pk_length)
uint no_fragments; uint no_fragments;
{ {
#if MYSQL_VERSION_ID >= 50000 #if MYSQL_VERSION_ID >= 50000
uint acc_row_size= 25+2; uint acc_row_size= 25 + /*safety margin*/ 2;
#else #else
uint acc_row_size= pk_length*4; uint acc_row_size= pk_length*4;
/* add acc overhead */ /* add acc overhead */
if (pk_length <= 8) if (pk_length <= 8) /* main page will set the limit */
acc_row_size+= 25+2; /* main page will set the limit */ acc_row_size+= 25 + /*safety margin*/ 2;
else else /* overflow page will set the limit */
acc_row_size+= 4+4; /* overflow page will set the limit */ acc_row_size+= 4 + /*safety margin*/ 4;
#endif #endif
ulonglong acc_fragment_size= 512*1024*1024; ulonglong acc_fragment_size= 512*1024*1024;
ulonglong max_rows= form->max_rows; ulonglong max_rows= form->max_rows;
#if MYSQL_VERSION_ID >= 50100
no_fragments= ((max_rows*acc_row_size)/acc_fragment_size+1
+1/*correct rounding*/)/2;
#else
no_fragments= (max_rows*acc_row_size)/acc_fragment_size+1; no_fragments= (max_rows*acc_row_size)/acc_fragment_size+1;
#endif
} }
{ {
uint no_nodes= g_ndb_cluster_connection->no_db_nodes(); uint no_nodes= g_ndb_cluster_connection->no_db_nodes();
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment