Make SQLString reallocation addaptive

Avoid doing reallocs
Prealloc some strings / provide extension allocation size to some strings
This gave a 25 % speedup in some mysql-test-run tests.



mysys/safemalloc.c:
  More DBUG_PRINT
sql/net_serv.cc:
  Make all mallocs() look the similar. (just-for-safety fix)
sql/protocol.cc:
  Ensure that communication packet buffer is allocated.
  (It's freed by stored precedures and some DLL statements)
sql/sp.cc:
  Fixed valgrind warning
sql/sql_select.cc:
  Set extent allocation for buffer that has a lot of append() calls.
sql/sql_show.cc:
  Fixed wrong usage of string buffer. Old code worked in test suite 'just-by-chance'
sql/sql_string.cc:
  Call realloc_with_extra_if_needed() in append() functions.
sql/sql_string.h:
  Added 'extra_alloc' member, to specify chunck size for realloc().
  extra_alloc is addaptive to catch cases where preallocation of buffers is not done properly.
  Simplified free() to allow compiler to optimize things better (and to keep things consistent).
  Fixed shrink() to take into account the extra memory added to the Alloced_length in realloc(). This saves us a realloc() per query.
sql/sql_test.cc:
  Set extent allocation for buffer that has a lot of append() calls.
sql/table.cc:
  Set extent allocation for buffer that has a lot of append() calls.

1 files changed, 3 insertions, 1 deletions

diff --git a/sql/table.cc b/sql/table.cc
index 7a2581d5ab8..45c1f5ab378 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -3328,11 +3328,13 @@ Table_check_intact::check(TABLE *table, const TABLE_FIELD_DEF *table_def)
       is backward compatible.
     */
   }
-  char buffer[STRING_BUFFER_USUAL_SIZE];
+  char buffer[1024];
   for (i=0 ; i < table_def->count; i++, field_def++)
   {
     String sql_type(buffer, sizeof(buffer), system_charset_info);
     sql_type.length(0);
+    /* Allocate min 256 characters at once */
+    sql_type.extra_allocation(256);
     if (i < table->s->fields)
     {
       Field *field= table->field[i];