First push for WL#3146 "less locking in auto_increment". It is a 0-real-change patch.

New prototype for get_auto_increment() (but new arguments not yet used), to be able
to reserve a finite interval of auto_increment values from cooperating engines.
A hint on how many values to reserve is found in handler::estimation_rows_to_insert,
filled by ha_start_bulk_insert(), new wrapper around start_bulk_insert().
NOTE: this patch changes nothing, for all engines. But it makes the API ready for those
engines which will want to do reservation.
More csets will come to complete WL#3146.


sql/ha_berkeley.cc:
  update to new prototype of get_auto_increment
sql/ha_berkeley.h:
  update to new prototype of get_auto_increment
sql/ha_heap.cc:
  update to new prototype of get_auto_increment
sql/ha_heap.h:
  update to new prototype of get_auto_increment
sql/ha_innodb.cc:
  update to new prototype of get_auto_increment
sql/ha_innodb.h:
  update to new prototype of get_auto_increment
sql/ha_myisam.cc:
  update to new prototype of get_auto_increment
sql/ha_myisam.h:
  update to new prototype of get_auto_increment
sql/ha_ndbcluster.cc:
  update to new prototype of get_auto_increment
sql/ha_ndbcluster.h:
  update to new prototype of get_auto_increment
sql/ha_partition.cc:
  update to new prototype of get_auto_increment
sql/ha_partition.h:
  update to new prototype of get_auto_increment
sql/handler.cc:
  new prototype of get_auto_increment, comments, preparation for when the MySQL layer is capable
  of getting finite auto_increment intervals from cooperating engines.
sql/handler.h:
  a wrapper around start_bulk_insert(): ha_bulk_insert(), which stores the argument (number
  of rows expected for insertion) into a member of handler: estimation_rows_to_insert.
  This member will soon be used to decide how much auto_increment values we want to reserve
  from cooperating engines.
  New prototype for get_auto_increment, preparing for cooperating engines to reserve finite auto_increment
  intervals.
  release_auto_increment() will be used by the MySQL layer to inform the engine that it has
  not used all of the interval (engine can reclaim it).
sql/log.cc:
  note for the future
sql/log_event.cc:
  name of wrapper
sql/sql_insert.cc:
  name of wrapper. When done with inserting, return unused auto_inc values to engine.
sql/sql_load.cc:
  name of wrapper. When done with inserting, return unused auto_inc values to engine.
sql/sql_select.cc:
  name of wrapper
sql/sql_table.cc:
  name of wrapper
storage/archive/ha_archive.cc:
  update to new prototype of get_auto_increment.
  Archive reserves only one value (Archive's god - Brian - told me that's the truth).
storage/archive/ha_archive.h:
  update to new prototype of get_auto_increment()

1 files changed, 16 insertions, 3 deletions

diff --git a/sql/ha_myisam.cc b/sql/ha_myisam.cc
index 40081c975c8..a3d032d0b91 100644
--- a/sql/ha_myisam.cc
+++ b/sql/ha_myisam.cc
@@ -1690,7 +1690,10 @@ int ha_myisam::rename_table(const char * from, const char * to)
 }
 
 
-ulonglong ha_myisam::get_auto_increment()
+void ha_myisam::get_auto_increment(ulonglong offset, ulonglong increment,
+                                   ulonglong nb_desired_values,
+                                   ulonglong *first_value,
+                                   ulonglong *nb_reserved_values)
 {
   ulonglong nr;
   int error;
@@ -1699,7 +1702,10 @@ ulonglong ha_myisam::get_auto_increment()
   if (!table->s->next_number_key_offset)
   {						// Autoincrement at key-start
     ha_myisam::info(HA_STATUS_AUTO);
-    return auto_increment_value;
+    *first_value= auto_increment_value;
+    /* MyISAM has only table-level lock, so reserves to +inf */
+    *nb_reserved_values= ULONGLONG_MAX;
+    return;
   }
 
   /* it's safe to call the following if bulk_insert isn't on */
@@ -1720,7 +1726,14 @@ ulonglong ha_myisam::get_auto_increment()
          val_int_offset(table->s->rec_buff_length)+1);
   }
   extra(HA_EXTRA_NO_KEYREAD);
-  return nr;
+  *first_value= nr;
+  /*
+    MySQL needs to call us for next row: assume we are inserting ("a",null)
+    here, we return 3, and next this statement will want to insert ("b",null):
+    there is no reason why ("b",3+1) would be the good row to insert: maybe it
+    already exists, maybe 3+1 is too large...
+  */
+  *nb_reserved_values= 1;
 }