PS-9647: MySQL Perf Improvements (deque) #5611
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kamil-holubicki
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aybek,
percona-ysorokin,
inikep,
VarunNagaraju,
satya-bodapati,
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| @@ -7049,11 +7049,13 @@ static uint get_semi_join_select_list_index(Item_field *item_field) { | |||
| if (emb_sj_nest && emb_sj_nest->is_sj_or_aj_nest()) { | |||
| const mem_root_deque<Item *> &items = | |||
| emb_sj_nest->nested_join->sj_inner_exprs; | |||
| for (size_t i = 0; i < items.size(); i++) { | |||
| const Item *sel_item = items[i]; | |||
| size_t i = 0; | |||
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variable name i is too short, expected at least 2 characters
sql/sql_parse.cc
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| @@ -1304,7 +1304,9 @@ void free_items(Item *item) { | |||
| */ | |||
| void cleanup_items(Item *item) { | |||
| DBUG_TRACE; | |||
| for (; item; item = item->next_free) item->cleanup(); | |||
| for (; item; item = item->next_free) { | |||
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implicit conversion Item * -> bool
Suggested change
| for (; item; item = item->next_free) { | |
| for (; item != nullptr; item = item->next_free) { |
| */ | ||
| template <class Element_type> | ||
| template <class T> | ||
| class mem_root_deque { |
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And more generic question...
Why do we need this class at all? How is it different from
template <class T>
using mem_root_deque = std::list<T, Mem_root_allocator<T>> list_;
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for pop_back/pop_front we need a wrapper, because for std::list, if the list is empty, the behavior is undefined.
Also, there is no indexing operator in std::list
https://perconadev.atlassian.net/browse/PS-9647 This patch uses list instead of deque for memory efficiency reasons, primarily to optimize operations like bulk insert
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PS-9647: MySQL Perf Improvements (deque)
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https://perconadev.atlassian.net/browse/PS-9647
This patch uses list instead of deque for memory efficiency reasons, primarily to optimize operations like bulk insert