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| author | Sergei Golubchik <serg@mariadb.org> | 2017-06-21 16:07:54 +0200 |
|---|---|---|
| committer | Sergei Golubchik <serg@mariadb.org> | 2019-04-24 16:06:54 +0200 |
| commit | 979cad229148ba8d28d94c1ca621bacd11847b66 (patch) | |
| tree | 127609c70f86a96f7b8b5ee8e1348b9c33673f2c /sql/item_sum.h | |
| parent | e91fd8783a5343dcd32917e35fa03b2dbe00021d (diff) | |
| download | mariadb-git-979cad229148ba8d28d94c1ca621bacd11847b66.tar.gz | |
MDEV-9531 GROUP_CONCAT with ORDER BY inside takes a lot of memory while it's executed
group concat tree is allocated in a memroot, so the only way to free
memory is to copy a part of the tree into a new memroot.
track the accumilated length of the result, and when it crosses
the threshold - copy the result into a new tree, free the old one.
Diffstat (limited to 'sql/item_sum.h')
| -rw-r--r-- | sql/item_sum.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sql/item_sum.h b/sql/item_sum.h index dc672486bce..001d1d13fe4 100644 --- a/sql/item_sum.h +++ b/sql/item_sum.h @@ -1431,6 +1431,7 @@ class Item_func_group_concat : public Item_sum String *separator; TREE tree_base; TREE *tree; + size_t tree_len; Item **ref_pointer_array; /** @@ -1468,6 +1469,8 @@ class Item_func_group_concat : public Item_sum element_count count __attribute__((unused)), void* item_arg); + bool repack_tree(THD *thd); + public: Item_func_group_concat(THD *thd, Name_resolution_context *context_arg, bool is_distinct, List<Item> *is_select, |