Allocate HEAP blocks in smaller blocks to get better memory utilization and...

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)
-    records_in_block=10;
+  if (records_in_block < HP_MIN_RECORDS_IN_BLOCK && max_records)
+    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)
-#endif
+    if ((MyFlags & MY_ZEROFILL) || !sf_malloc_quick)
       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;