bzr commit into mysql-next-mr-wl5569 branch (andrei.elkin:3321) WL#5569

[Andrei Elkin]

#At file:///home/andrei/MySQL/BZR/2a-23May/WL/mysql-next-mr-wl5569/ based on revid:andrei.elkin@stripped

 3321 Andrei Elkin	2011-06-24
      wl#5569 MTS
      
      This patch makes a bit of cleanup, addresses one memory-allocation todo and completes fixing valgrind report (rpl_parallel_start_stop) due to strings allocation in Slave_job_group items.

    modified:
      sql/log_event.cc
      sql/rpl_rli.h
      sql/rpl_rli_pdb.cc
      sql/rpl_rli_pdb.h
      sql/rpl_slave.cc
=== modified file 'sql/log_event.cc'
--- a/sql/log_event.cc	2011-06-22 17:54:23 +0000
+++ b/sql/log_event.cc	2011-06-24 12:38:19 +0000
@@ -2475,7 +2475,7 @@ Slave_worker *Log_event::get_slave_worke
   {
     int i= 0;
     num_dbs= mts_number_dbs();
-    List_iterator<char> it(*mts_get_dbs(thd->mem_root));
+    List_iterator<char> it(*mts_get_dbs(&rli->mts_coor_mem_root));
     it++;
 
     ret_worker= rli->last_assigned_worker;
@@ -2526,14 +2526,6 @@ Slave_worker *Log_event::get_slave_worke
     }
 
     DBUG_ASSERT(i == num_dbs || num_dbs == OVER_MAX_DBS_IN_EVENT_MTS);
-
-    // TODO: convert to C's private mem_root to reset not per event but rather realrely.
-
-    // Releasing the Coord's mem-root from the updated dbs. It's safe to do at this
-    // point because the root is no longer needed along remained part of Coordinator's
-    // execution flow.
-    
-    free_root(thd->mem_root, MYF(MY_KEEP_PREALLOC));
   }
   else 
   {
@@ -2609,8 +2601,14 @@ Slave_worker *Log_event::get_slave_worke
 
     DBUG_ASSERT(ret_worker != NULL);
     
-    // TODO: UNTIL option, throw an error when relay-log reading
-    // starts from inside of a group!!
+    /*
+      The following two blocks are executed if the worker has not been
+      notified about new relay-log or a new checkpoints. 
+      Relay-log string is freed by Coordinator, Worker deallocates
+      strings in the checkpoint block.
+      However if the worker exits earlier reclaiming for both happens anyway at
+      GAQ delete.
+    */
 
     if (!ret_worker->relay_log_change_notified) // ALFRANIO
     {
@@ -2633,13 +2631,6 @@ Slave_worker *Log_event::get_slave_worke
       ret_worker->relay_log_change_notified= TRUE;
     }
 
-    /*
-      This executed if the worker has not been notified by a recent
-      set of checkpoints.
-      Notice that it is the worker responsibility to deallocate the
-      memory allocated at this point. This is done upon committing
-      this job.
-    */
     if (!ret_worker->checkpoint_notified)
     {
       ptr_g->checkpoint_log_name= (char *)
@@ -2661,6 +2652,9 @@ Slave_worker *Log_event::get_slave_worke
     ptr_g->checkpoint_seqno= rli->checkpoint_seqno;
     ptr_g->ts= when + (time_t) exec_time;
     rli->checkpoint_seqno++;
+
+    // reclaiming resources allocated during the group scheduling
+    free_root(&rli->mts_coor_mem_root, MYF(MY_KEEP_PREALLOC));
   }
   
   return ret_worker;

=== modified file 'sql/rpl_rli.h'
--- a/sql/rpl_rli.h	2011-06-22 17:54:23 +0000
+++ b/sql/rpl_rli.h	2011-06-24 12:38:19 +0000
@@ -460,6 +460,7 @@ public:
   ulong opt_slave_parallel_workers; // auxiliary cache for ::opt_slave_parallel_workers
   ulong slave_parallel_workers;     // the one slave session time number of workers
   ulong recovery_parallel_workers; // number of workers while recovering.
+
   /* 
      A sorted array of Worker current assignements number to provide
      approximate view on Workers loading.
@@ -473,6 +474,7 @@ public:
   ulong mts_recovery_group_cnt; // number of groups to execute at recovery
   ulong mts_recovery_index;     // running index of recoverable groups
   bool mts_recovery_group_seen_begin;
+
   /*
     temporary tables are held by Coordinator though are created and dropped
     explicilty by Workers. The following lock has to be taken by either party
@@ -480,16 +482,27 @@ public:
     find, drop, create, open.
   */
   mysql_mutex_t mts_temp_tables_lock;
+
   /*
-    While Worker utilize its thd->mem_root, Coordinator adopts a specific mem-root:
+    Coordinator's specific mem-root to hold various temporary data while
+    the current group is being schedulled. The root is shunk to default size
+    at the end of the group distribution.
   */
   MEM_ROOT mts_coor_mem_root;
+
   /*
-    While distibuting events basing on their properties MTS Coordinator
-    changes its mts group status.
-    Transition from NOT_IN to IN happens once an event is scheduled to a Worker.
-    Reverse transition occures when Coordinator requests synchronization with
-    Workers demanding them to complete their assignments.
+    While distibuting events basing on their properties MTS
+    Coordinator changes its mts group status.
+    Transition normally flowws to follow `=>' arrows on the diagram:
+
+            +----------------------------+
+            V                            |
+    MTS_NOT_IN_GROUP =>                  |
+        {MTS_IN_GROUP => MTS_END_GROUP --+} while (!killed) => MTS_KILLED_GROUP
+      
+    though MTS_END_GROUP has `->' link to MTS_NOT_IN_GROUP
+    when Coordinator synchronizes with Workers by demanding them to complete their
+    assignments.
   */
   enum
   {

=== modified file 'sql/rpl_rli_pdb.cc'
--- a/sql/rpl_rli_pdb.cc	2011-06-21 16:10:54 +0000
+++ b/sql/rpl_rli_pdb.cc	2011-06-24 12:38:19 +0000
@@ -1135,6 +1135,14 @@ void Slave_committed_queue::free_dynamic
     {
       my_free(ptr_g->group_relay_log_name);
     }
+    if (ptr_g->checkpoint_log_name)
+    {
+      my_free(ptr_g->checkpoint_log_name);
+    }
+    if (ptr_g->checkpoint_relay_log_name)
+    {
+      my_free(ptr_g->checkpoint_relay_log_name);
+    }
   }
 }
 

=== modified file 'sql/rpl_rli_pdb.h'
--- a/sql/rpl_rli_pdb.h	2011-06-21 14:05:32 +0000
+++ b/sql/rpl_rli_pdb.h	2011-06-24 12:38:19 +0000
@@ -210,6 +210,7 @@ public:
     {
       delete_dynamic(&last_done);
       my_free(lwm.group_relay_log_name);
+      free_dynamic_items();  // free possibly left allocated strings in GAQ list
     }
   }
 

=== modified file 'sql/rpl_slave.cc'
--- a/sql/rpl_slave.cc	2011-06-22 18:17:43 +0000
+++ b/sql/rpl_slave.cc	2011-06-24 12:38:19 +0000
@@ -4490,8 +4490,6 @@ void slave_stop_workers(Relay_log_info *
 
   rli->mts_group_status= Relay_log_info::MTS_NOT_IN_GROUP;
   destroy_hash_workers(rli);
-  // free possibly allocated strings in GAQ's list
-  rli->gaq->free_dynamic_items();
   delete rli->gaq;
   delete_dynamic(&rli->least_occupied_workers);    // least occupied
   delete_dynamic(&rli->curr_group_da);             // GCDA


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