From a175314c3e5827eb193872241446f2f8f5c9d33c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 4 May 2024 20:07:14 +0200 Subject: Adding upstream version 1:10.5.12. Signed-off-by: Daniel Baumann --- sql/sql_expression_cache.h | 159 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 159 insertions(+) create mode 100644 sql/sql_expression_cache.h (limited to 'sql/sql_expression_cache.h') diff --git a/sql/sql_expression_cache.h b/sql/sql_expression_cache.h new file mode 100644 index 00000000..031773ad --- /dev/null +++ b/sql/sql_expression_cache.h @@ -0,0 +1,159 @@ +/* + Copyright (c) 2010, 2011, Monty Program Ab + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */ + +#ifndef SQL_EXPRESSION_CACHE_INCLUDED +#define SQL_EXPRESSION_CACHE_INCLUDED + +#include "sql_select.h" + + +/** + Interface for expression cache + + @note + Parameters of an expression cache interface are set on the creation of the + cache. They are passed when a cache object of the implementation class is + constructed. That's why they are not visible in this interface. +*/ + +extern ulong subquery_cache_miss, subquery_cache_hit; + +class Expression_cache :public Sql_alloc +{ +public: + enum result {ERROR, HIT, MISS}; + + Expression_cache(){}; + virtual ~Expression_cache() {}; + /** + Shall check the presence of expression value in the cache for a given + set of values of the expression parameters. Return the result of the + expression if it's found in the cache. + */ + virtual result check_value(Item **value)= 0; + /** + Shall put the value of an expression for given set of its parameters + into the expression cache + */ + virtual my_bool put_value(Item *value)= 0; + + /** + Print cache parameters + */ + virtual void print(String *str, enum_query_type query_type)= 0; + + /** + Is this cache initialized + */ + virtual bool is_inited()= 0; + /** + Initialize this cache + */ + virtual void init()= 0; + + /** + Save this object's statistics into Expression_cache_tracker object + */ + virtual void update_tracker()= 0; +}; + +struct st_table_ref; +struct st_join_table; +class Item_field; + + +class Expression_cache_tracker :public Sql_alloc +{ +public: + enum expr_cache_state {UNINITED, STOPPED, OK}; + Expression_cache_tracker(Expression_cache *c) : + cache(c), hit(0), miss(0), state(UNINITED) + {} + + Expression_cache *cache; + ulong hit, miss; + enum expr_cache_state state; + + static const char* state_str[3]; + void set(ulong h, ulong m, enum expr_cache_state s) + {hit= h; miss= m; state= s;} + + void fetch_current_stats() + { + if (cache) + cache->update_tracker(); + } +}; + + +/** + Implementation of expression cache over a temporary table +*/ + +class Expression_cache_tmptable :public Expression_cache +{ +public: + Expression_cache_tmptable(THD *thd, List &dependants, Item *value); + virtual ~Expression_cache_tmptable(); + virtual result check_value(Item **value); + virtual my_bool put_value(Item *value); + + void print(String *str, enum_query_type query_type); + bool is_inited() { return inited; }; + void init(); + + void set_tracker(Expression_cache_tracker *st) + { + tracker= st; + update_tracker(); + } + virtual void update_tracker() + { + if (tracker) + { + tracker->set(hit, miss, (inited ? (cache_table ? + Expression_cache_tracker::OK : + Expression_cache_tracker::STOPPED) : + Expression_cache_tracker::UNINITED)); + } + } + +private: + void disable_cache(); + + /* tmp table parameters */ + TMP_TABLE_PARAM cache_table_param; + /* temporary table to store this cache */ + TABLE *cache_table; + /* Thread handle for the temporary table */ + THD *table_thd; + /* EXPALIN/ANALYZE statistics */ + Expression_cache_tracker *tracker; + /* TABLE_REF for index lookup */ + struct st_table_ref ref; + /* Cached result */ + Item_field *cached_result; + /* List of parameter items */ + List &items; + /* Value Item example */ + Item *val; + /* hit/miss counters */ + ulong hit, miss; + /* Set on if the object has been successfully initialized with init() */ + bool inited; +}; + +#endif /* SQL_EXPRESSION_CACHE_INCLUDED */ -- cgit v1.2.3