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-rw-r--r--sql/sql_class.h3
-rw-r--r--sql/uniques.cc11
2 files changed, 13 insertions, 1 deletions
diff --git a/sql/sql_class.h b/sql/sql_class.h
index 9071a2db516..7ca3896a69d 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -5216,6 +5216,9 @@ public:
{
ulonglong max_elems_in_tree=
max_in_memory_size / ALIGN_SIZE(sizeof(TREE_ELEMENT)+key_size);
+
+ if (max_elems_in_tree == 0)
+ max_elems_in_tree= 1;
return (int) (sizeof(uint)*(1 + nkeys/max_elems_in_tree));
}
diff --git a/sql/uniques.cc b/sql/uniques.cc
index 03f25d31384..b9cb50543e2 100644
--- a/sql/uniques.cc
+++ b/sql/uniques.cc
@@ -317,6 +317,9 @@ double Unique::get_use_cost(uint *buffer, size_t nkeys, uint key_size,
max_elements_in_tree= ((size_t) max_in_memory_size /
ALIGN_SIZE(sizeof(TREE_ELEMENT)+key_size));
+ if (max_elements_in_tree == 0)
+ max_elements_in_tree= 1;
+
n_full_trees= nkeys / max_elements_in_tree;
last_tree_elems= nkeys % max_elements_in_tree;
@@ -781,7 +784,13 @@ bool Unique::get(TABLE *table)
/* Not enough memory; Save the result to file && free memory used by tree */
if (flush())
return 1;
- size_t buff_sz= (max_in_memory_size / full_size + 1) * full_size;
+
+ /*
+ merge_buffer must fit at least MERGEBUFF2 + 1 keys, because
+ merge_index() can merge that many BUFFPEKs at once. The extra space for
+ one key for Sort_param::unique_buff
+ */
+ size_t buff_sz= MY_MAX(MERGEBUFF2+1, max_in_memory_size/full_size+1) * full_size;
if (!(sort_buffer= (uchar*) my_malloc(buff_sz, MYF(MY_THREAD_SPECIFIC|MY_WME))))
return 1;