Allocate HEAP blocks in smaller blocks to get better memory utilization and more speed when used with safemalloc.

Don't initalize memory areas when run with --skip-safemalloc.

Docs/manual.texi

@@ -46929,10 +46929,12 @@ not yet 100% confident in this code.
 @node News-3.23.54, News-3.23.53, News-3.23.x, News-3.23.x
 @appendixsubsec Changes in release 3.23.54
 @itemize
+@item
 Fixed reference to freed memory when doing complicated @code{GROUP BY
 ... ORDER BY} queries.  Symptom was that @code{mysqld} died in function
 @code{send_fields}.
-queries.
+@item
+Allocate heap rows in smaller blocks to get better memory usage.
 @end itemize
 
 @node News-3.23.53, News-3.23.52, News-3.23.54, News-3.23.x

heap/heapdef.h

@@ -22,6 +22,17 @@
 #endif
 #include "heap.h"			/* Structs & some defines */
 
+/*
+  When allocating keys /rows in the internal block structure, do it
+  within the following boundaries.
+
+  The challenge is to find the balance between allocate as few blocks
+  as possible and keep memory consumption down.
+*/
+
+#define HP_MIN_RECORDS_IN_BLOCK 16
+#define HP_MAX_RECORDS_IN_BLOCK 8192
+
 	/* Some extern variables */
 
 extern LIST *heap_open_list,*heap_share_list;

heap/hp_open.c

@@ -157,8 +157,14 @@ static void init_block(HP_BLOCK *block, uint reclength, ulong min_records,
     max_records=1000;			/* As good as quess as anything */
   recbuffer=(uint) (reclength+sizeof(byte**)-1) & ~(sizeof(byte**)-1);
   records_in_block=max_records/10;
-  if (records_in_block < 10 && max_records)
+  if (records_in_block < HP_MIN_RECORDS_IN_BLOCK && max_records)
-    records_in_block=10;
+    records_in_block= HP_MIN_RECORDS_IN_BLOCK;
+  /*
+    Don't allocate too many rows at one time too keep memory consumption
+    done when we don't need it.
+  */
+  if (records_in_block > HP_MAX_RECORDS_IN_BLOCK)
+    records_in_block= HP_MAX_RECORDS_IN_BLOCK;
   if (!records_in_block || records_in_block*recbuffer >
       (my_default_record_cache_size-sizeof(HP_PTRS)*HP_MAX_LEVELS))
     records_in_block=(my_default_record_cache_size-sizeof(HP_PTRS)*

mysys/safemalloc.c

@@ -194,9 +194,7 @@ gptr _mymalloc (uint uSize, const char *sFile, uint uLine, myf MyFlags)
     pthread_mutex_unlock(&THR_LOCK_malloc);
 
     /* Set the memory to the aribtrary wierd value */
-#ifdef HAVE_purify
+    if ((MyFlags & MY_ZEROFILL) || !sf_malloc_quick)
-    if (MyFlags & MY_ZEROFILL)
-#endif
       bfill(&pTmp -> aData[sf_malloc_prehunc],uSize,
 	    (char) (MyFlags & MY_ZEROFILL ? 0 : ALLOC_VAL));
     /* Return a pointer to the real data */
@@ -315,7 +313,8 @@ void _myfree (gptr pPtr, const char *sFile, uint uLine, myf myflags)
 
 #ifndef HAVE_purify
   /* Mark this data as free'ed */
-  bfill(&pRec->aData[sf_malloc_prehunc],pRec->uDataSize,(pchar) FREE_VAL);
+  if (!sf_malloc_quick)
+    bfill(&pRec->aData[sf_malloc_prehunc],pRec->uDataSize,(pchar) FREE_VAL);
 #endif
   *((long*) ((char*) &pRec -> lSpecialValue+sf_malloc_prehunc)) = ~MAGICKEY;