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Diffstat (limited to 'sql/item_sum.h')
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diff --git a/sql/item_sum.h b/sql/item_sum.h new file mode 100644 index 00000000..73087340 --- /dev/null +++ b/sql/item_sum.h @@ -0,0 +1,2101 @@ +#ifndef ITEM_SUM_INCLUDED +#define ITEM_SUM_INCLUDED +/* Copyright (c) 2000, 2013 Oracle and/or its affiliates. + Copyright (c) 2008, 2023, MariaDB Corporation. + + 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 St, Fifth Floor, Boston, MA 02110-1335 USA */ + + +/* classes for sum functions */ + +#ifdef USE_PRAGMA_INTERFACE +#pragma interface /* gcc class implementation */ +#endif + +#include <my_tree.h> +#include "sql_udf.h" /* udf_handler */ + +class Item_sum; +class Aggregator_distinct; +class Aggregator_simple; + +/** + The abstract base class for the Aggregator_* classes. + It implements the data collection functions (setup/add/clear) + as either pass-through to the real functionality or + as collectors into an Unique (for distinct) structure. + + Note that update_field/reset_field are not in that + class, because they're simply not called when + GROUP BY/DISTINCT can be handled with help of index on grouped + fields (quick_group = 0); +*/ + +class Aggregator : public Sql_alloc +{ + friend class Item_sum; + friend class Item_sum_sum; + friend class Item_sum_count; + friend class Item_sum_avg; + + /* + All members are protected as this class is not usable outside of an + Item_sum descendant. + */ +protected: + /* the aggregate function class to act on */ + Item_sum *item_sum; + +public: + Aggregator (Item_sum *arg): item_sum(arg) {} + virtual ~Aggregator () = default; /* Keep gcc happy */ + + enum Aggregator_type { SIMPLE_AGGREGATOR, DISTINCT_AGGREGATOR }; + virtual Aggregator_type Aggrtype() = 0; + + /** + Called before adding the first row. + Allocates and sets up the internal aggregation structures used, + e.g. the Unique instance used to calculate distinct. + */ + virtual bool setup(THD *) = 0; + + /** + Called when we need to wipe out all the data from the aggregator : + all the values acumulated and all the state. + Cleans up the internal structures and resets them to their initial state. + */ + virtual void clear() = 0; + + /** + Called when there's a new value to be aggregated. + Updates the internal state of the aggregator to reflect the new value. + */ + virtual bool add() = 0; + + /** + Called when there are no more data and the final value is to be retrieved. + Finalises the state of the aggregator, so the final result can be retrieved. + */ + virtual void endup() = 0; + + /** Decimal value of being-aggregated argument */ + virtual my_decimal *arg_val_decimal(my_decimal * value) = 0; + /** Floating point value of being-aggregated argument */ + virtual double arg_val_real() = 0; + /** + NULLness of being-aggregated argument. + + @param use_null_value Optimization: to determine if the argument is NULL + we must, in the general case, call is_null() on it, which itself might + call val_*() on it, which might be costly. If you just have called + arg_val*(), you can pass use_null_value=true; this way, arg_is_null() + might avoid is_null() and instead do a cheap read of the Item's null_value + (updated by arg_val*()). + */ + virtual bool arg_is_null(bool use_null_value) = 0; +}; + + +class st_select_lex; +class Window_spec; + +/** + Class Item_sum is the base class used for special expressions that SQL calls + 'set functions'. These expressions are formed with the help of aggregate + functions such as SUM, MAX, GROUP_CONCAT etc. + + GENERAL NOTES + + A set function cannot be used in certain positions where expressions are + accepted. There are some quite explicable restrictions for the usage of + set functions. + + In the query: + SELECT AVG(b) FROM t1 WHERE SUM(b) > 20 GROUP by a + the usage of the set function AVG(b) is legal, while the usage of SUM(b) + is illegal. A WHERE condition must contain expressions that can be + evaluated for each row of the table. Yet the expression SUM(b) can be + evaluated only for each group of rows with the same value of column a. + In the query: + SELECT AVG(b) FROM t1 WHERE c > 30 GROUP BY a HAVING SUM(b) > 20 + both set function expressions AVG(b) and SUM(b) are legal. + + We can say that in a query without nested selects an occurrence of a + set function in an expression of the SELECT list or/and in the HAVING + clause is legal, while in the WHERE clause it's illegal. + + The general rule to detect whether a set function is legal in a query with + nested subqueries is much more complicated. + + Consider the the following query: + SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL (SELECT t2.c FROM t2 WHERE SUM(t1.b) < t2.c). + The set function SUM(b) is used here in the WHERE clause of the subquery. + Nevertheless it is legal since it is under the HAVING clause of the query + to which this function relates. The expression SUM(t1.b) is evaluated + for each group defined in the main query, not for groups of the subquery. + + The problem of finding the query where to aggregate a particular + set function is not so simple as it seems to be. + + In the query: + SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL(SELECT t2.c FROM t2 GROUP BY t2.c + HAVING SUM(t1.a) < t2.c) + the set function can be evaluated for both outer and inner selects. + If we evaluate SUM(t1.a) for the outer query then we get the value of t1.a + multiplied by the cardinality of a group in table t1. In this case + in each correlated subquery SUM(t1.a) is used as a constant. But we also + can evaluate SUM(t1.a) for the inner query. In this case t1.a will be a + constant for each correlated subquery and summation is performed + for each group of table t2. + (Here it makes sense to remind that the query + SELECT c FROM t GROUP BY a HAVING SUM(1) < a + is quite legal in our SQL). + + So depending on what query we assign the set function to we + can get different result sets. + + The general rule to detect the query where a set function is to be + evaluated can be formulated as follows. + Consider a set function S(E) where E is an expression with occurrences + of column references C1, ..., CN. Resolve these column references against + subqueries that contain the set function S(E). Let Q be the innermost + subquery of those subqueries. (It should be noted here that S(E) + in no way can be evaluated in the subquery embedding the subquery Q, + otherwise S(E) would refer to at least one unbound column reference) + If S(E) is used in a construct of Q where set functions are allowed then + we evaluate S(E) in Q. + Otherwise we look for a innermost subquery containing S(E) of those where + usage of S(E) is allowed. + + Let's demonstrate how this rule is applied to the following queries. + + 1. SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL(SELECT t2.b FROM t2 GROUP BY t2.b + HAVING t2.b > ALL(SELECT t3.c FROM t3 GROUP BY t3.c + HAVING SUM(t1.a+t2.b) < t3.c)) + For this query the set function SUM(t1.a+t2.b) depends on t1.a and t2.b + with t1.a defined in the outermost query, and t2.b defined for its + subquery. The set function is in the HAVING clause of the subquery and can + be evaluated in this subquery. + + 2. SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL(SELECT t2.b FROM t2 + WHERE t2.b > ALL (SELECT t3.c FROM t3 GROUP BY t3.c + HAVING SUM(t1.a+t2.b) < t3.c)) + Here the set function SUM(t1.a+t2.b)is in the WHERE clause of the second + subquery - the most upper subquery where t1.a and t2.b are defined. + If we evaluate the function in this subquery we violate the context rules. + So we evaluate the function in the third subquery (over table t3) where it + is used under the HAVING clause. + + 3. SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL(SELECT t2.b FROM t2 + WHERE t2.b > ALL (SELECT t3.c FROM t3 + WHERE SUM(t1.a+t2.b) < t3.c)) + In this query evaluation of SUM(t1.a+t2.b) is not legal neither in the second + nor in the third subqueries. So this query is invalid. + + Mostly set functions cannot be nested. In the query + SELECT t1.a from t1 GROUP BY t1.a HAVING AVG(SUM(t1.b)) > 20 + the expression SUM(b) is not acceptable, though it is under a HAVING clause. + Yet it is acceptable in the query: + SELECT t.1 FROM t1 GROUP BY t1.a HAVING SUM(t1.b) > 20. + + An argument of a set function does not have to be a reference to a table + column as we saw it in examples above. This can be a more complex expression + SELECT t1.a FROM t1 GROUP BY t1.a HAVING SUM(t1.b+1) > 20. + The expression SUM(t1.b+1) has a very clear semantics in this context: + we sum up the values of t1.b+1 where t1.b varies for all values within a + group of rows that contain the same t1.a value. + + A set function for an outer query yields a constant within a subquery. So + the semantics of the query + SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a IN (SELECT t2.c FROM t2 GROUP BY t2.c + HAVING AVG(t2.c+SUM(t1.b)) > 20) + is still clear. For a group of the rows with the same t1.a values we + calculate the value of SUM(t1.b). This value 's' is substituted in the + the subquery: + SELECT t2.c FROM t2 GROUP BY t2.c HAVING AVG(t2.c+s) + than returns some result set. + + By the same reason the following query with a subquery + SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a IN (SELECT t2.c FROM t2 GROUP BY t2.c + HAVING AVG(SUM(t1.b)) > 20) + is also acceptable. + + IMPLEMENTATION NOTES + + Three methods were added to the class to check the constraints specified + in the previous section. These methods utilize several new members. + + The field 'nest_level' contains the number of the level for the subquery + containing the set function. The main SELECT is of level 0, its subqueries + are of levels 1, the subqueries of the latter are of level 2 and so on. + + The field 'aggr_level' is to contain the nest level of the subquery + where the set function is aggregated. + + The field 'max_arg_level' is for the maximum of the nest levels of the + unbound column references occurred in the set function. A column reference + is unbound within a set function if it is not bound by any subquery + used as a subexpression in this function. A column reference is bound by + a subquery if it is a reference to the column by which the aggregation + of some set function that is used in the subquery is calculated. + For the set function used in the query + SELECT t1.a FROM t1 GROUP BY t1.a + HAVING t1.a > ALL(SELECT t2.b FROM t2 GROUP BY t2.b + HAVING t2.b > ALL(SELECT t3.c FROM t3 GROUP BY t3.c + HAVING SUM(t1.a+t2.b) < t3.c)) + the value of max_arg_level is equal to 1 since t1.a is bound in the main + query, and t2.b is bound by the first subquery whose nest level is 1. + Obviously a set function cannot be aggregated in the subquery whose + nest level is less than max_arg_level. (Yet it can be aggregated in the + subqueries whose nest level is greater than max_arg_level.) + In the query + SELECT t.a FROM t1 HAVING AVG(t1.a+(SELECT MIN(t2.c) FROM t2)) + the value of the max_arg_level for the AVG set function is 0 since + the reference t2.c is bound in the subquery. + + The field 'max_sum_func_level' is to contain the maximum of the + nest levels of the set functions that are used as subexpressions of + the arguments of the given set function, but not aggregated in any + subquery within this set function. A nested set function s1 can be + used within set function s0 only if s1.max_sum_func_level < + s0.max_sum_func_level. Set function s1 is considered as nested + for set function s0 if s1 is not calculated in any subquery + within s0. + + A set function that is used as a subexpression in an argument of another + set function refers to the latter via the field 'in_sum_func'. + + The condition imposed on the usage of set functions are checked when + we traverse query subexpressions with the help of the recursive method + fix_fields. When we apply this method to an object of the class + Item_sum, first, on the descent, we call the method init_sum_func_check + that initialize members used at checking. Then, on the ascent, we + call the method check_sum_func that validates the set function usage + and reports an error if it is illegal. + The method register_sum_func serves to link the items for the set functions + that are aggregated in the embedding (sub)queries. Circular chains of such + functions are attached to the corresponding st_select_lex structures + through the field inner_sum_func_list. + + Exploiting the fact that the members mentioned above are used in one + recursive function we could have allocated them on the thread stack. + Yet we don't do it now. + + We assume that the nesting level of subquries does not exceed 127. + TODO: to catch queries where the limit is exceeded to make the + code clean here. + + @note + The implementation takes into account the used strategy: + - Items resolved at optimization phase return 0 from Item_sum::used_tables(). + - Items that depend on the number of join output records, but not columns of + any particular table (like COUNT(*)), returm 0 from Item_sum::used_tables(), + but still return false from Item_sum::const_item(). +*/ + +class Item_sum :public Item_func_or_sum +{ + friend class Aggregator_distinct; + friend class Aggregator_simple; + +protected: + /** + Aggregator class instance. Not set initially. Allocated only after + it is determined if the incoming data are already distinct. + */ + Aggregator *aggr; + +private: + /** + Used in making ROLLUP. Set for the ROLLUP copies of the original + Item_sum and passed to create_tmp_field() to cause it to work + over the temp table buffer that is referenced by + Item_result_field::result_field. + */ + bool force_copy_fields; + + /** + Indicates how the aggregate function was specified by the parser : + 1 if it was written as AGGREGATE(DISTINCT), + 0 if it was AGGREGATE() + */ + bool with_distinct; + + /* TRUE if this is aggregate function of a window function */ + bool window_func_sum_expr_flag; + +public: + + bool has_force_copy_fields() const { return force_copy_fields; } + bool has_with_distinct() const { return with_distinct; } + + enum Sumfunctype + { COUNT_FUNC, COUNT_DISTINCT_FUNC, SUM_FUNC, SUM_DISTINCT_FUNC, AVG_FUNC, + AVG_DISTINCT_FUNC, MIN_FUNC, MAX_FUNC, STD_FUNC, + VARIANCE_FUNC, SUM_BIT_FUNC, UDF_SUM_FUNC, GROUP_CONCAT_FUNC, + ROW_NUMBER_FUNC, RANK_FUNC, DENSE_RANK_FUNC, PERCENT_RANK_FUNC, + CUME_DIST_FUNC, NTILE_FUNC, FIRST_VALUE_FUNC, LAST_VALUE_FUNC, + NTH_VALUE_FUNC, LEAD_FUNC, LAG_FUNC, PERCENTILE_CONT_FUNC, + PERCENTILE_DISC_FUNC, SP_AGGREGATE_FUNC, JSON_ARRAYAGG_FUNC, + JSON_OBJECTAGG_FUNC + }; + + Item **ref_by; /* pointer to a ref to the object used to register it */ + Item_sum *next; /* next in the circular chain of registered objects */ + Item_sum *in_sum_func; /* embedding set function if any */ + st_select_lex * aggr_sel; /* select where the function is aggregated */ + int8 nest_level; /* number of the nesting level of the set function */ + int8 aggr_level; /* nesting level of the aggregating subquery */ + int8 max_arg_level; /* max level of unbound column references */ + int8 max_sum_func_level;/* max level of aggregation for embedded functions */ + + /* + true (the default value) means this aggregate function can be computed + with TemporaryTableWithPartialSums algorithm (see end_update()). + false means this aggregate function needs OrderedGroupBy algorithm (see + end_write_group()). + */ + bool quick_group; + /* + This list is used by the check for mixing non aggregated fields and + sum functions in the ONLY_FULL_GROUP_BY_MODE. We save all outer fields + directly or indirectly used under this function it as it's unclear + at the moment of fixing outer field whether it's aggregated or not. + */ + List<Item_field> outer_fields; + +protected: + /* + Copy of the arguments list to hold the original set of arguments. + Used in EXPLAIN EXTENDED instead of the current argument list because + the current argument list can be altered by usage of temporary tables. + */ + Item **orig_args, *tmp_orig_args[2]; + + static size_t ram_limitation(THD *thd); +public: + // Methods used by ColumnStore + Item **get_orig_args() const { return orig_args; } +public: + + void mark_as_sum_func(); + Item_sum(THD *thd): Item_func_or_sum(thd), quick_group(1) + { + mark_as_sum_func(); + init_aggregator(); + } + Item_sum(THD *thd, Item *a): Item_func_or_sum(thd, a), quick_group(1), + orig_args(tmp_orig_args) + { + mark_as_sum_func(); + init_aggregator(); + } + Item_sum(THD *thd, Item *a, Item *b): Item_func_or_sum(thd, a, b), + quick_group(1), orig_args(tmp_orig_args) + { + mark_as_sum_func(); + init_aggregator(); + } + Item_sum(THD *thd, List<Item> &list); + //Copy constructor, need to perform subselects with temporary tables + Item_sum(THD *thd, Item_sum *item); + enum Type type() const override { return SUM_FUNC_ITEM; } + virtual enum Sumfunctype sum_func () const=0; + bool is_aggr_sum_func() + { + switch (sum_func()) { + case COUNT_FUNC: + case COUNT_DISTINCT_FUNC: + case SUM_FUNC: + case SUM_DISTINCT_FUNC: + case AVG_FUNC: + case AVG_DISTINCT_FUNC: + case MIN_FUNC: + case MAX_FUNC: + case STD_FUNC: + case VARIANCE_FUNC: + case SUM_BIT_FUNC: + case UDF_SUM_FUNC: + case GROUP_CONCAT_FUNC: + case JSON_ARRAYAGG_FUNC: + return true; + default: + return false; + } + } + /** + Resets the aggregate value to its default and aggregates the current + value of its attribute(s). + */ + inline bool reset_and_add() + { + aggregator_clear(); + return aggregator_add(); + }; + + /* + Called when new group is started and results are being saved in + a temporary table. Similarly to reset_and_add() it resets the + value to its default and aggregates the value of its + attribute(s), but must also store it in result_field. + This set of methods (result_item(), reset_field, update_field()) of + Item_sum is used only if quick_group is not null. Otherwise + copy_or_same() is used to obtain a copy of this item. + */ + virtual void reset_field()=0; + /* + Called for each new value in the group, when temporary table is in use. + Similar to add(), but uses temporary table field to obtain current value, + Updated value is then saved in the field. + */ + virtual void update_field()=0; + bool fix_length_and_dec(THD *thd) override + { + set_maybe_null(); + null_value=1; + return FALSE; + } + virtual Item *result_item(THD *thd, Field *field); + + void update_used_tables() override; + COND *build_equal_items(THD *thd, COND_EQUAL *inherited, + bool link_item_fields, + COND_EQUAL **cond_equal_ref) override + { + /* + Item_sum (and derivants) of the original WHERE/HAVING clauses + should already be replaced to Item_aggregate_ref by the time when + build_equal_items() is called. See Item::split_sum_func2(). + */ + DBUG_ASSERT(0); + return Item::build_equal_items(thd, inherited, link_item_fields, + cond_equal_ref); + } + bool is_null() override { return null_value; } + /** + make_const() + Called if we've managed to calculate the value of this Item in + opt_sum_query(), hence it can be considered constant at all subsequent + steps. + */ + void make_const () + { + used_tables_cache= 0; + const_item_cache= true; + } + void reset_forced_const() { const_item_cache= false; } + bool const_during_execution() const override { return false; } + void print(String *str, enum_query_type query_type) override; + void fix_num_length_and_dec(); + + /** + Mark an aggregate as having no rows. + + This function is called by the execution engine to assign 'NO ROWS + FOUND' value to an aggregate item, when the underlying result set + has no rows. Such value, in a general case, may be different from + the default value of the item after 'clear()': e.g. a numeric item + may be initialized to 0 by clear() and to NULL by + no_rows_in_result(). + */ + void no_rows_in_result() override + { + set_aggregator(current_thd, with_distinct ? + Aggregator::DISTINCT_AGGREGATOR : + Aggregator::SIMPLE_AGGREGATOR); + aggregator_clear(); + } + virtual void make_unique() { force_copy_fields= TRUE; } + Item *get_tmp_table_item(THD *thd) override; + virtual Field *create_tmp_field(MEM_ROOT *root, bool group, TABLE *table); + Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src, + const Tmp_field_param *param) override + { + return create_tmp_field(root, param->group(), table); + } + bool collect_outer_ref_processor(void *param) override; + bool init_sum_func_check(THD *thd); + bool check_sum_func(THD *thd, Item **ref); + bool register_sum_func(THD *thd, Item **ref); + st_select_lex *depended_from() + { return (nest_level == aggr_level ? 0 : aggr_sel); } + + Item *get_arg(uint i) const { return args[i]; } + Item *set_arg(uint i, THD *thd, Item *new_val); + uint get_arg_count() const { return arg_count; } + virtual Item **get_args() { return fixed() ? orig_args : args; } + + /* Initialization of distinct related members */ + void init_aggregator() + { + aggr= NULL; + with_distinct= FALSE; + force_copy_fields= FALSE; + } + + /** + Called to initialize the aggregator. + */ + + inline bool aggregator_setup(THD *thd) { return aggr->setup(thd); }; + + /** + Called to cleanup the aggregator. + */ + + inline void aggregator_clear() { aggr->clear(); } + + /** + Called to add value to the aggregator. + */ + + inline bool aggregator_add() { return aggr->add(); }; + + /* stores the declared DISTINCT flag (from the parser) */ + void set_distinct(bool distinct) + { + with_distinct= distinct; + quick_group= with_distinct ? 0 : 1; + } + + /* + Set the type of aggregation : DISTINCT or not. + + May be called multiple times. + */ + + int set_aggregator(THD *thd, Aggregator::Aggregator_type aggregator); + + virtual void clear()= 0; + virtual bool add()= 0; + virtual bool setup(THD *thd) { return false; } + + virtual bool supports_removal() const { return false; } + virtual void remove() { DBUG_ASSERT(0); } + + void cleanup() override; + bool check_vcol_func_processor(void *arg) override; + virtual void setup_window_func(THD *thd, Window_spec *window_spec) {} + void mark_as_window_func_sum_expr() { window_func_sum_expr_flag= true; } + bool is_window_func_sum_expr() { return window_func_sum_expr_flag; } + virtual void setup_caches(THD *thd) {}; + virtual void set_partition_row_count(ulonglong count) { DBUG_ASSERT(0); } +}; + + +class Unique; + + +/** + The distinct aggregator. + Implements AGGFN (DISTINCT ..) + Collects all the data into an Unique (similarly to what Item_sum + does currently when with_distinct=true) and then (if applicable) iterates over + the list of unique values and pumps them back into its object +*/ + +class Aggregator_distinct : public Aggregator +{ + friend class Item_sum_sum; + + /* + flag to prevent consecutive runs of endup(). Normally in endup there are + expensive calculations (like walking the distinct tree for example) + which we must do only once if there are no data changes. + We can re-use the data for the second and subsequent val_xxx() calls. + endup_done set to TRUE also means that the calculated values for + the aggregate functions are correct and don't need recalculation. + */ + bool endup_done; + + /* + Used depending on the type of the aggregate function and the presence of + blob columns in it: + - For COUNT(DISTINCT) and no blob fields this points to a real temporary + table. It's used as a hash table. + - For AVG/SUM(DISTINCT) or COUNT(DISTINCT) with blob fields only the + in-memory data structure of a temporary table is constructed. + It's used by the Field classes to transform data into row format. + */ + TABLE *table; + + /* + An array of field lengths on row allocated and used only for + COUNT(DISTINCT) with multiple columns and no blobs. Used in + Aggregator_distinct::composite_key_cmp (called from Unique to compare + nodes + */ + uint32 *field_lengths; + + /* + Used in conjunction with 'table' to support the access to Field classes + for COUNT(DISTINCT). Needed by copy_fields()/copy_funcs(). + */ + TMP_TABLE_PARAM *tmp_table_param; + + /* + If there are no blobs in the COUNT(DISTINCT) arguments, we can use a tree, + which is faster than heap table. In that case, we still use the table + to help get things set up, but we insert nothing in it. + For AVG/SUM(DISTINCT) we always use this tree (as it takes a single + argument) to get the distinct rows. + */ + Unique *tree; + + /* + The length of the temp table row. Must be a member of the class as it + gets passed down to simple_raw_key_cmp () as a compare function argument + to Unique. simple_raw_key_cmp () is used as a fast comparison function + when the entire row can be binary compared. + */ + uint tree_key_length; + + /* + Set to true if the result is known to be always NULL. + If set deactivates creation and usage of the temporary table (in the + 'table' member) and the Unique instance (in the 'tree' member) as well as + the calculation of the final value on the first call to + Item_[sum|avg|count]::val_xxx(). + */ + bool always_null; + + /** + When feeding back the data in endup() from Unique/temp table back to + Item_sum::add() methods we must read the data from Unique (and not + recalculate the functions that are given as arguments to the aggregate + function. + This flag is to tell the arg_*() methods to take the data from the Unique + instead of calling the relevant val_..() method. + */ + bool use_distinct_values; + +public: + Aggregator_distinct (Item_sum *sum) : + Aggregator(sum), table(NULL), tmp_table_param(NULL), tree(NULL), + always_null(false), use_distinct_values(false) {} + virtual ~Aggregator_distinct (); + Aggregator_type Aggrtype() { return DISTINCT_AGGREGATOR; } + + bool setup(THD *); + void clear(); + bool add(); + void endup(); + virtual my_decimal *arg_val_decimal(my_decimal * value); + virtual double arg_val_real(); + virtual bool arg_is_null(bool use_null_value); + + bool unique_walk_function(void *element); + bool unique_walk_function_for_count(void *element); + static int composite_key_cmp(void* arg, uchar* key1, uchar* key2); +}; + + +/** + The pass-through aggregator. + Implements AGGFN (DISTINCT ..) by knowing it gets distinct data on input. + So it just pumps them back to the Item_sum descendant class. +*/ +class Aggregator_simple : public Aggregator +{ +public: + + Aggregator_simple (Item_sum *sum) : + Aggregator(sum) {} + Aggregator_type Aggrtype() { return Aggregator::SIMPLE_AGGREGATOR; } + + bool setup(THD * thd) { return item_sum->setup(thd); } + void clear() { item_sum->clear(); } + bool add() { return item_sum->add(); } + void endup() {}; + virtual my_decimal *arg_val_decimal(my_decimal * value); + virtual double arg_val_real(); + virtual bool arg_is_null(bool use_null_value); +}; + + +class Item_sum_num :public Item_sum +{ +public: + Item_sum_num(THD *thd): Item_sum(thd) {} + Item_sum_num(THD *thd, Item *item_par): + Item_sum(thd, item_par) {} + Item_sum_num(THD *thd, Item *a, Item* b): + Item_sum(thd, a, b) {} + Item_sum_num(THD *thd, List<Item> &list): + Item_sum(thd, list) {} + Item_sum_num(THD *thd, Item_sum_num *item): + Item_sum(thd, item) {} + bool fix_fields(THD *, Item **); +}; + + +class Item_sum_double :public Item_sum_num +{ +public: + Item_sum_double(THD *thd): Item_sum_num(thd) {} + Item_sum_double(THD *thd, Item *item_par): Item_sum_num(thd, item_par) {} + Item_sum_double(THD *thd, List<Item> &list): Item_sum_num(thd, list) {} + Item_sum_double(THD *thd, Item_sum_double *item) :Item_sum_num(thd, item) {} + longlong val_int() override + { + return val_int_from_real(); + } + String *val_str(String*str) override + { + return val_string_from_real(str); + } + my_decimal *val_decimal(my_decimal *to) override + { + return val_decimal_from_real(to); + } + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return get_date_from_real(thd, ltime, fuzzydate); + } + const Type_handler *type_handler() const override + { return &type_handler_double; } +}; + + +class Item_sum_int :public Item_sum_num +{ +public: + Item_sum_int(THD *thd): Item_sum_num(thd) {} + Item_sum_int(THD *thd, Item *item_par): Item_sum_num(thd, item_par) {} + Item_sum_int(THD *thd, List<Item> &list): Item_sum_num(thd, list) {} + Item_sum_int(THD *thd, Item_sum_int *item) :Item_sum_num(thd, item) {} + double val_real() override { DBUG_ASSERT(fixed()); return (double) val_int(); } + String *val_str(String*str) override; + my_decimal *val_decimal(my_decimal *) override; + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return get_date_from_int(thd, ltime, fuzzydate); + } + bool fix_length_and_dec(THD *thd) override + { + decimals=0; + max_length=21; + base_flags&= ~item_base_t::MAYBE_NULL; + null_value=0; + return FALSE; } +}; + + +class Item_sum_sum :public Item_sum_num, + public Type_handler_hybrid_field_type +{ +protected: + bool direct_added; + bool direct_reseted_field; + bool direct_sum_is_null; + double direct_sum_real; + double sum; + my_decimal direct_sum_decimal; + my_decimal dec_buffs[2]; + uint curr_dec_buff; + bool fix_length_and_dec(THD *thd) override; + +public: + Item_sum_sum(THD *thd, Item *item_par, bool distinct): + Item_sum_num(thd, item_par), direct_added(FALSE), + direct_reseted_field(FALSE) + { + set_distinct(distinct); + } + Item_sum_sum(THD *thd, Item_sum_sum *item); + enum Sumfunctype sum_func() const override + { + return has_with_distinct() ? SUM_DISTINCT_FUNC : SUM_FUNC; + } + void cleanup() override; + void direct_add(my_decimal *add_sum_decimal); + void direct_add(double add_sum_real, bool add_sum_is_null); + void clear() override; + bool add() override; + double val_real() override; + longlong val_int() override; + String *val_str(String*str) override; + my_decimal *val_decimal(my_decimal *) override; + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate); + } + const Type_handler *type_handler() const override + { return Type_handler_hybrid_field_type::type_handler(); } + void fix_length_and_dec_double(); + void fix_length_and_dec_decimal(); + void reset_field() override; + void update_field() override; + void no_rows_in_result() override {} + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING name_distinct= { STRING_WITH_LEN("sum(distinct ")}; + static LEX_CSTRING name_normal= { STRING_WITH_LEN("sum(") }; + return has_with_distinct() ? name_distinct : name_normal; + } + Item *copy_or_same(THD* thd) override; + void remove() override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_sum>(thd, this); } + + bool supports_removal() const override + { + return true; + } + +private: + void add_helper(bool perform_removal); + ulonglong count; +}; + + +class Item_sum_count :public Item_sum_int +{ + bool direct_counted; + bool direct_reseted_field; + longlong direct_count; + longlong count; + + friend class Aggregator_distinct; + + void clear() override; + bool add() override; + void cleanup() override; + void remove() override; + +public: + Item_sum_count(THD *thd, Item *item_par): + Item_sum_int(thd, item_par), direct_counted(FALSE), + direct_reseted_field(FALSE), count(0) + {} + + /** + Constructs an instance for COUNT(DISTINCT) + + @param list a list of the arguments to the aggregate function + + This constructor is called by the parser only for COUNT (DISTINCT). + */ + + Item_sum_count(THD *thd, List<Item> &list): + Item_sum_int(thd, list), direct_counted(FALSE), + direct_reseted_field(FALSE), count(0) + { + set_distinct(TRUE); + } + Item_sum_count(THD *thd, Item_sum_count *item): + Item_sum_int(thd, item), direct_counted(FALSE), + direct_reseted_field(FALSE), count(item->count) + {} + enum Sumfunctype sum_func () const override + { + return has_with_distinct() ? COUNT_DISTINCT_FUNC : COUNT_FUNC; + } + void no_rows_in_result() override { count=0; } + void make_const(longlong count_arg) + { + count=count_arg; + Item_sum::make_const(); + } + const Type_handler *type_handler() const override + { return &type_handler_slonglong; } + longlong val_int() override; + void reset_field() override; + void update_field() override; + void direct_add(longlong add_count); + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING name_distinct= { STRING_WITH_LEN("count(distinct ")}; + static LEX_CSTRING name_normal= { STRING_WITH_LEN("count(") }; + return has_with_distinct() ? name_distinct : name_normal; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_count>(thd, this); } + + bool supports_removal() const override + { + return true; + } +}; + + +class Item_sum_avg :public Item_sum_sum +{ +public: + // TODO-cvicentiu given that Item_sum_sum now uses a counter of its own, in + // order to implement remove(), it is possible to remove this member. + ulonglong count; + uint prec_increment; + uint f_precision, f_scale, dec_bin_size; + + Item_sum_avg(THD *thd, Item *item_par, bool distinct): + Item_sum_sum(thd, item_par, distinct), count(0) + {} + Item_sum_avg(THD *thd, Item_sum_avg *item) + :Item_sum_sum(thd, item), count(item->count), + prec_increment(item->prec_increment) {} + + void fix_length_and_dec_double(); + void fix_length_and_dec_decimal(); + bool fix_length_and_dec(THD *thd) override; + enum Sumfunctype sum_func () const override + { + return has_with_distinct() ? AVG_DISTINCT_FUNC : AVG_FUNC; + } + void clear() override; + bool add() override; + void remove() override; + double val_real() override; + // In SPs we might force the "wrong" type with select into a declare variable + longlong val_int() override { return val_int_from_real(); } + my_decimal *val_decimal(my_decimal *) override; + String *val_str(String *str) override; + void reset_field() override; + void update_field() override; + Item *result_item(THD *thd, Field *field) override; + void no_rows_in_result() override {} + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING name_distinct= { STRING_WITH_LEN("avg(distinct ")}; + static LEX_CSTRING name_normal= { STRING_WITH_LEN("avg(") }; + return has_with_distinct() ? name_distinct : name_normal; + } + Item *copy_or_same(THD* thd) override; + Field *create_tmp_field(MEM_ROOT *root, bool group, TABLE *table) override; + void cleanup() override + { + count= 0; + Item_sum_sum::cleanup(); + } + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_avg>(thd, this); } + + bool supports_removal() const override + { + return true; + } +}; + + +/* + variance(a) = + + = sum (ai - avg(a))^2 / count(a) ) + = sum (ai^2 - 2*ai*avg(a) + avg(a)^2) / count(a) + = (sum(ai^2) - sum(2*ai*avg(a)) + sum(avg(a)^2))/count(a) = + = (sum(ai^2) - 2*avg(a)*sum(a) + count(a)*avg(a)^2)/count(a) = + = (sum(ai^2) - 2*sum(a)*sum(a)/count(a) + count(a)*sum(a)^2/count(a)^2 )/count(a) = + = (sum(ai^2) - 2*sum(a)^2/count(a) + sum(a)^2/count(a) )/count(a) = + = (sum(ai^2) - sum(a)^2/count(a))/count(a) + +But, this falls prey to catastrophic cancellation. Instead, use the recurrence formulas + + M_{1} = x_{1}, ~ M_{k} = M_{k-1} + (x_{k} - M_{k-1}) / k newline + S_{1} = 0, ~ S_{k} = S_{k-1} + (x_{k} - M_{k-1}) times (x_{k} - M_{k}) newline + for 2 <= k <= n newline + ital variance = S_{n} / (n-1) + +*/ + +class Stddev +{ + double m_m; + double m_s; + ulonglong m_count; +public: + Stddev() :m_m(0), m_s(0), m_count(0) { } + Stddev(double nr) :m_m(nr), m_s(0.0), m_count(1) { } + Stddev(const uchar *); + void to_binary(uchar *) const; + void recurrence_next(double nr); + double result(bool is_simple_variance); + ulonglong count() const { return m_count; } + static uint32 binary_size() + { + return (uint32) (sizeof(double) * 2 + sizeof(ulonglong)); + }; +}; + + + +class Item_sum_variance :public Item_sum_double +{ + Stddev m_stddev; + bool fix_length_and_dec(THD *thd) override; + +public: + uint sample; + uint prec_increment; + + Item_sum_variance(THD *thd, Item *item_par, uint sample_arg): + Item_sum_double(thd, item_par), + sample(sample_arg) + {} + Item_sum_variance(THD *thd, Item_sum_variance *item); + Sumfunctype sum_func () const override { return VARIANCE_FUNC; } + void fix_length_and_dec_double(); + void fix_length_and_dec_decimal(); + void clear() override final; + bool add() override final; + double val_real() override; + void reset_field() override final; + void update_field() override final; + Item *result_item(THD *thd, Field *field) override; + void no_rows_in_result() override final {} + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING name_sample= { STRING_WITH_LEN("var_samp(")}; + static LEX_CSTRING name_normal= { STRING_WITH_LEN("variance(") }; + return sample ? name_sample : name_normal; + } + Item *copy_or_same(THD* thd) override; + Field *create_tmp_field(MEM_ROOT *root, bool group, TABLE *table) override + final; + void cleanup() override final + { + m_stddev= Stddev(); + Item_sum_double::cleanup(); + } + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_variance>(thd, this); } +}; + +/* + standard_deviation(a) = sqrt(variance(a)) +*/ + +class Item_sum_std final :public Item_sum_variance +{ + public: + Item_sum_std(THD *thd, Item *item_par, uint sample_arg): + Item_sum_variance(thd, item_par, sample_arg) {} + Item_sum_std(THD *thd, Item_sum_std *item) + :Item_sum_variance(thd, item) + {} + enum Sumfunctype sum_func () const override final { return STD_FUNC; } + double val_real() override final; + Item *result_item(THD *thd, Field *field) override final; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING std_name= {STRING_WITH_LEN("std(") }; + static LEX_CSTRING stddev_samp_name= {STRING_WITH_LEN("stddev_samp(") }; + return sample ? stddev_samp_name : std_name; + } + Item *copy_or_same(THD* thd) override final; + Item *get_copy(THD *thd) override final + { return get_item_copy<Item_sum_std>(thd, this); } +}; + + +class Item_sum_hybrid : public Item_sum, + public Type_handler_hybrid_field_type +{ +public: + Item_sum_hybrid(THD *thd, Item *item_par): + Item_sum(thd, item_par), + Type_handler_hybrid_field_type(&type_handler_slonglong) + { collation.set(&my_charset_bin); } + Item_sum_hybrid(THD *thd, Item *a, Item *b): + Item_sum(thd, a, b), + Type_handler_hybrid_field_type(&type_handler_slonglong) + { collation.set(&my_charset_bin); } + Item_sum_hybrid(THD *thd, Item_sum_hybrid *item) + :Item_sum(thd, item), + Type_handler_hybrid_field_type(item) + { } + const Type_handler *type_handler() const override + { return Type_handler_hybrid_field_type::type_handler(); } + bool fix_length_and_dec_generic(); + bool fix_length_and_dec_numeric(const Type_handler *h); + bool fix_length_and_dec_string(); +}; + + +// This class is a string or number function depending on num_func +class Arg_comparator; +class Item_cache; +class Item_sum_min_max :public Item_sum_hybrid +{ +protected: + bool direct_added; + Item *direct_item; + Item_cache *value, *arg_cache; + Arg_comparator *cmp; + int cmp_sign; + bool was_values; // Set if we have found at least one row (for max/min only) + bool was_null_value; + +public: + Item_sum_min_max(THD *thd, Item *item_par,int sign): + Item_sum_hybrid(thd, item_par), + direct_added(FALSE), value(0), arg_cache(0), cmp(0), + cmp_sign(sign), was_values(TRUE) + { collation.set(&my_charset_bin); } + Item_sum_min_max(THD *thd, Item_sum_min_max *item) + :Item_sum_hybrid(thd, item), + direct_added(FALSE), value(item->value), arg_cache(0), + cmp_sign(item->cmp_sign), was_values(item->was_values) + { } + bool fix_fields(THD *, Item **) override; + bool fix_length_and_dec(THD *thd) override; + void setup_hybrid(THD *thd, Item *item, Item *value_arg); + void clear() override; + void direct_add(Item *item); + double val_real() override; + longlong val_int() override; + my_decimal *val_decimal(my_decimal *) override; + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override; + void reset_field() override; + String *val_str(String *) override; + bool val_native(THD *thd, Native *) override; + const Type_handler *real_type_handler() const override + { + return get_arg(0)->real_type_handler(); + } + const TYPELIB *get_typelib() const override { return args[0]->get_typelib(); } + void update_field() override; + void min_max_update_str_field(); + void min_max_update_real_field(); + void min_max_update_int_field(); + void min_max_update_decimal_field(); + void min_max_update_native_field(); + void cleanup() override; + bool any_value() { return was_values; } + void no_rows_in_result() override; + void restore_to_before_no_rows_in_result() override; + Field *create_tmp_field(MEM_ROOT *root, bool group, TABLE *table) override; + void setup_caches(THD *thd) override + { setup_hybrid(thd, arguments()[0], NULL); } +}; + + +class Item_sum_min final :public Item_sum_min_max +{ +public: + Item_sum_min(THD *thd, Item *item_par): Item_sum_min_max(thd, item_par, 1) {} + Item_sum_min(THD *thd, Item_sum_min *item) :Item_sum_min_max(thd, item) {} + enum Sumfunctype sum_func () const override {return MIN_FUNC;} + + bool add() override; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_name= {STRING_WITH_LEN("min(") }; + return sum_name; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_min>(thd, this); } +}; + + +class Item_sum_max final :public Item_sum_min_max +{ +public: + Item_sum_max(THD *thd, Item *item_par): Item_sum_min_max(thd, item_par, -1) {} + Item_sum_max(THD *thd, Item_sum_max *item) :Item_sum_min_max(thd, item) {} + enum Sumfunctype sum_func () const override {return MAX_FUNC;} + + bool add() override; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_name= {STRING_WITH_LEN("max(") }; + return sum_name; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_max>(thd, this); } +}; + + +class Item_sum_bit :public Item_sum_int +{ +public: + Item_sum_bit(THD *thd, Item *item_par, ulonglong reset_arg): + Item_sum_int(thd, item_par), reset_bits(reset_arg), bits(reset_arg), + as_window_function(FALSE), num_values_added(0) {} + Item_sum_bit(THD *thd, Item_sum_bit *item): + Item_sum_int(thd, item), reset_bits(item->reset_bits), bits(item->bits), + as_window_function(item->as_window_function), + num_values_added(item->num_values_added) + { + if (as_window_function) + memcpy(bit_counters, item->bit_counters, sizeof(bit_counters)); + } + enum Sumfunctype sum_func () const override { return SUM_BIT_FUNC;} + void clear() override; + longlong val_int() override; + void reset_field() override; + void update_field() override; + const Type_handler *type_handler() const override + { return &type_handler_ulonglong; } + bool fix_length_and_dec(THD *thd) override + { + if (args[0]->check_type_can_return_int(func_name_cstring())) + return true; + decimals= 0; max_length=21; unsigned_flag= 1; + base_flags&= ~item_base_t::MAYBE_NULL; + null_value= 0; + return FALSE; + } + void cleanup() override + { + bits= reset_bits; + if (as_window_function) + clear_as_window(); + Item_sum_int::cleanup(); + } + void setup_window_func(THD *thd __attribute__((unused)), + Window_spec *window_spec __attribute__((unused))) + override + { + as_window_function= TRUE; + clear_as_window(); + } + void remove() override + { + if (as_window_function) + { + remove_as_window(args[0]->val_int()); + return; + } + // Unless we're counting bits, we can not remove anything. + DBUG_ASSERT(0); + } + + bool supports_removal() const override + { + return true; + } + +protected: + enum bit_counters { NUM_BIT_COUNTERS= 64 }; + ulonglong reset_bits,bits; + /* + Marks whether the function is to be computed as a window function. + */ + bool as_window_function; + // When used as an aggregate window function, we need to store + // this additional information. + ulonglong num_values_added; + ulonglong bit_counters[NUM_BIT_COUNTERS]; + bool add_as_window(ulonglong value); + bool remove_as_window(ulonglong value); + bool clear_as_window(); + virtual void set_bits_from_counters()= 0; +}; + + +class Item_sum_or final :public Item_sum_bit +{ +public: + Item_sum_or(THD *thd, Item *item_par): Item_sum_bit(thd, item_par, 0) {} + Item_sum_or(THD *thd, Item_sum_or *item) :Item_sum_bit(thd, item) {} + bool add() override; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_name= {STRING_WITH_LEN("bit_or(") }; + return sum_name; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_or>(thd, this); } + +private: + void set_bits_from_counters() override; +}; + + +class Item_sum_and final :public Item_sum_bit +{ +public: + Item_sum_and(THD *thd, Item *item_par): + Item_sum_bit(thd, item_par, ULONGLONG_MAX) {} + Item_sum_and(THD *thd, Item_sum_and *item) :Item_sum_bit(thd, item) {} + bool add() override; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_min_name= {STRING_WITH_LEN("bit_and(") }; + return sum_min_name; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_and>(thd, this); } + +private: + void set_bits_from_counters() override; +}; + +class Item_sum_xor final :public Item_sum_bit +{ +public: + Item_sum_xor(THD *thd, Item *item_par): Item_sum_bit(thd, item_par, 0) {} + Item_sum_xor(THD *thd, Item_sum_xor *item) :Item_sum_bit(thd, item) {} + bool add() override; + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_min_name= {STRING_WITH_LEN("bit_xor(") }; + return sum_min_name; + } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_xor>(thd, this); } + +private: + void set_bits_from_counters() override; +}; + +class sp_head; +class sp_name; +class Query_arena; +struct st_sp_security_context; + +/* + Item_sum_sp handles STORED AGGREGATE FUNCTIONS + + Each Item_sum_sp represents a custom aggregate function. Inside the + function's body, we require at least one occurrence of FETCH GROUP NEXT ROW + instruction. This cursor is what makes custom stored aggregates possible. + + During computation the function's add method is called. This in turn performs + an execution of the function. The function will execute from the current + function context (and instruction), if one exists, or from the start if not. + See Item_sp for more details. + + Upon encounter of FETCH GROUP NEXT ROW instruction, the function will pause + execution. We assume that the user has performed the necessary additions for + a row, between two encounters of FETCH GROUP NEXT ROW. + + Example: + create aggregate function f1(x INT) returns int + begin + declare continue handler for not found return s; + declare s int default 0 + loop + fetch group next row; + set s = s + x; + end loop; + end + + The function will always stop after an encounter of FETCH GROUP NEXT ROW, + except (!) on first encounter, as the value for the first row in the + group is already set in the argument x. This behaviour is done so when + a user writes a function, he should "logically" include FETCH GROUP NEXT ROW + before any "add" instructions in the stored function. This means however that + internally, the first occurrence doesn't stop the function. See the + implementation of FETCH GROUP NEXT ROW for details as to how it happens. + + Either way, one should assume that after calling "Item_sum_sp::add()" that + the values for that particular row have been added to the aggregation. + + To produce values for val_xxx methods we need an extra syntactic construct. + We require a continue handler when "no more rows are available". val_xxx + methods force a function return by executing the function again, while + setting a server flag that no more rows have been found. This implies + that val_xxx methods should only be called once per group however. + + Example: + DECLARE CONTINUE HANDLER FOR NOT FOUND RETURN ret_val; +*/ +class Item_sum_sp :public Item_sum, + public Item_sp +{ + private: + bool execute(); + +public: + Item_sum_sp(THD *thd, Name_resolution_context *context_arg, sp_name *name, + sp_head *sp); + + Item_sum_sp(THD *thd, Name_resolution_context *context_arg, sp_name *name, + sp_head *sp, List<Item> &list); + Item_sum_sp(THD *thd, Item_sum_sp *item); + + enum Sumfunctype sum_func () const override + { + return SP_AGGREGATE_FUNC; + } + Field *create_field_for_create_select(MEM_ROOT *root, TABLE *table) override + { + return create_table_field_from_handler(root, table); + } + bool fix_length_and_dec(THD *thd) override; + bool fix_fields(THD *thd, Item **ref) override; + LEX_CSTRING func_name_cstring() const override; + const Type_handler *type_handler() const override; + bool add() override; + + /* val_xx functions */ + longlong val_int() override + { + if(execute()) + return 0; + return sp_result_field->val_int(); + } + + double val_real() override + { + if(execute()) + return 0.0; + return sp_result_field->val_real(); + } + + my_decimal *val_decimal(my_decimal *dec_buf) override + { + if(execute()) + return NULL; + return sp_result_field->val_decimal(dec_buf); + } + + bool val_native(THD *thd, Native *to) override + { + return (null_value= execute()) || sp_result_field->val_native(to); + } + + String *val_str(String *str) override + { + String buf; + char buff[20]; + buf.set(buff, 20, str->charset()); + buf.length(0); + if (execute()) + return NULL; + /* + result_field will set buf pointing to internal buffer + of the resul_field. Due to this it will change any time + when SP is executed. In order to prevent occasional + corruption of returned value, we make here a copy. + */ + sp_result_field->val_str(&buf); + str->copy(buf); + return str; + } + void reset_field() override{DBUG_ASSERT(0);} + void update_field() override{DBUG_ASSERT(0);} + void clear() override; + void cleanup() override; + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return execute() || sp_result_field->get_date(ltime, fuzzydate); + } + inline Field *get_sp_result_field() + { + return sp_result_field; + } + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_sp>(thd, this); } + Item *copy_or_same(THD *thd) override; +}; + +/* Items to get the value of a stored sum function */ + +class Item_sum_field :public Item +{ +protected: + Field *field; +public: + Item_sum_field(THD *thd, Item_sum *item) + :Item(thd), field(item->result_field) + { + name= item->name; + set_maybe_null(); + decimals= item->decimals; + max_length= item->max_length; + unsigned_flag= item->unsigned_flag; + } + table_map used_tables() const override { return (table_map) 1L; } + Field *create_tmp_field_ex(MEM_ROOT *root, TABLE *table, Tmp_field_src *src, + const Tmp_field_param *param) override + { + return create_tmp_field_ex_simple(root, table, src, param); + } + void save_in_result_field(bool no_conversions) override { DBUG_ASSERT(0); } + bool check_vcol_func_processor(void *arg) override + { + return mark_unsupported_function(name.str, arg, VCOL_IMPOSSIBLE); + } + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate); + } +}; + + +class Item_avg_field :public Item_sum_field +{ +protected: + uint prec_increment; +public: + Item_avg_field(THD *thd, Item_sum_avg *item) + :Item_sum_field(thd, item), prec_increment(item->prec_increment) + { } + enum Type type() const override { return FIELD_AVG_ITEM; } + bool is_null() override { update_null_value(); return null_value; } +}; + + +class Item_avg_field_double :public Item_avg_field +{ +public: + Item_avg_field_double(THD *thd, Item_sum_avg *item) + :Item_avg_field(thd, item) + { } + const Type_handler *type_handler() const override + { return &type_handler_double; } + longlong val_int() override { return val_int_from_real(); } + my_decimal *val_decimal(my_decimal *dec) override + { return val_decimal_from_real(dec); } + String *val_str(String *str) override + { return val_string_from_real(str); } + double val_real() override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_avg_field_double>(thd, this); } +}; + + +class Item_avg_field_decimal :public Item_avg_field +{ + uint f_precision, f_scale, dec_bin_size; +public: + Item_avg_field_decimal(THD *thd, Item_sum_avg *item) + :Item_avg_field(thd, item), + f_precision(item->f_precision), + f_scale(item->f_scale), + dec_bin_size(item->dec_bin_size) + { } + const Type_handler *type_handler() const override + { return &type_handler_newdecimal; } + double val_real() override + { + return VDec(this).to_double(); + } + longlong val_int() override + { + return VDec(this).to_longlong(unsigned_flag); + } + String *val_str(String *str) override + { + return VDec(this).to_string_round(str, decimals); + } + my_decimal *val_decimal(my_decimal *) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_avg_field_decimal>(thd, this); } +}; + + +class Item_variance_field :public Item_sum_field +{ + uint sample; +public: + Item_variance_field(THD *thd, Item_sum_variance *item) + :Item_sum_field(thd, item), sample(item->sample) + { } + enum Type type() const override {return FIELD_VARIANCE_ITEM; } + double val_real() override; + longlong val_int() override { return val_int_from_real(); } + String *val_str(String *str) override + { return val_string_from_real(str); } + my_decimal *val_decimal(my_decimal *dec_buf) override + { return val_decimal_from_real(dec_buf); } + bool is_null() override { update_null_value(); return null_value; } + const Type_handler *type_handler() const override + { return &type_handler_double; } + Item *get_copy(THD *thd) override + { return get_item_copy<Item_variance_field>(thd, this); } +}; + + +class Item_std_field :public Item_variance_field +{ +public: + Item_std_field(THD *thd, Item_sum_std *item) + :Item_variance_field(thd, item) + { } + enum Type type() const override { return FIELD_STD_ITEM; } + double val_real() override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_std_field>(thd, this); } +}; + + +/* + User defined aggregates +*/ + +#ifdef HAVE_DLOPEN + +class Item_udf_sum : public Item_sum +{ +protected: + udf_handler udf; + +public: + Item_udf_sum(THD *thd, udf_func *udf_arg): + Item_sum(thd), udf(udf_arg) + { quick_group=0; } + Item_udf_sum(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_sum(thd, list), udf(udf_arg) + { quick_group=0;} + Item_udf_sum(THD *thd, Item_udf_sum *item) + :Item_sum(thd, item), udf(item->udf) + { udf.not_original= TRUE; } + LEX_CSTRING func_name_cstring() const override + { + const char *tmp= udf.name(); + return {tmp, strlen(tmp) }; + } + bool fix_fields(THD *thd, Item **ref) override + { + DBUG_ASSERT(fixed() == 0); + + if (init_sum_func_check(thd)) + return TRUE; + + base_flags|= item_base_t::FIXED; + /* + We set const_item_cache to false in constructors. + It can be later changed to "true", in a Item_sum::make_const() call. + No make_const() calls should have happened so far. + */ + DBUG_ASSERT(!const_item_cache); + if (udf.fix_fields(thd, this, this->arg_count, this->args)) + return TRUE; + /** + The above call for udf.fix_fields() updates + the Used_tables_and_const_cache part of "this" as if it was a regular + non-aggregate UDF function and can change both const_item_cache and + used_tables_cache members. + - The used_tables_cache will be re-calculated in update_used_tables() + which is called from check_sum_func() below. So we don't care about + its current value. + - The const_item_cache must stay "false" until a Item_sum::make_const() + call happens, if ever. So we need to reset const_item_cache back to + "false" here. + */ + const_item_cache= false; + memcpy (orig_args, args, sizeof (Item *) * arg_count); + return check_sum_func(thd, ref); + } + enum Sumfunctype sum_func () const override { return UDF_SUM_FUNC; } + virtual bool have_field_update(void) const { return 0; } + + void clear() override; + bool add() override; + bool supports_removal() const override; + void remove() override; + void reset_field() override {}; + void update_field() override {} + void cleanup() override; + void print(String *str, enum_query_type query_type) override; + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return type_handler()->Item_get_date_with_warn(thd, this, ltime, fuzzydate); + } +}; + + +class Item_sum_udf_float :public Item_udf_sum +{ + public: + Item_sum_udf_float(THD *thd, udf_func *udf_arg): + Item_udf_sum(thd, udf_arg) {} + Item_sum_udf_float(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_udf_sum(thd, udf_arg, list) {} + Item_sum_udf_float(THD *thd, Item_sum_udf_float *item) + :Item_udf_sum(thd, item) {} + longlong val_int() override { return val_int_from_real(); } + double val_real() override; + String *val_str(String*str) override; + my_decimal *val_decimal(my_decimal *) override; + const Type_handler *type_handler() const override + { return &type_handler_double; } + bool fix_length_and_dec(THD *thd) override + { fix_num_length_and_dec(); return FALSE; } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_udf_float>(thd, this); } +}; + + +class Item_sum_udf_int :public Item_udf_sum +{ +public: + Item_sum_udf_int(THD *thd, udf_func *udf_arg): + Item_udf_sum(thd, udf_arg) {} + Item_sum_udf_int(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_udf_sum(thd, udf_arg, list) {} + Item_sum_udf_int(THD *thd, Item_sum_udf_int *item) + :Item_udf_sum(thd, item) {} + longlong val_int() override; + double val_real() override + { DBUG_ASSERT(fixed()); return (double) Item_sum_udf_int::val_int(); } + String *val_str(String*str) override; + my_decimal *val_decimal(my_decimal *) override; + const Type_handler *type_handler() const override + { + if (unsigned_flag) + return &type_handler_ulonglong; + return &type_handler_slonglong; + } + bool fix_length_and_dec(THD *thd) override { decimals=0; max_length=21; return FALSE; } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_udf_int>(thd, this); } +}; + + +class Item_sum_udf_str :public Item_udf_sum +{ +public: + Item_sum_udf_str(THD *thd, udf_func *udf_arg): + Item_udf_sum(thd, udf_arg) {} + Item_sum_udf_str(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_udf_sum(thd, udf_arg, list) {} + Item_sum_udf_str(THD *thd, Item_sum_udf_str *item) + :Item_udf_sum(thd, item) {} + String *val_str(String *) override; + double val_real() override + { + int err_not_used; + char *end_not_used; + String *res; + res=val_str(&str_value); + return res ? res->charset()->strntod((char*) res->ptr(),res->length(), + &end_not_used, &err_not_used) : 0.0; + } + longlong val_int() override + { + int err_not_used; + char *end; + String *res; + CHARSET_INFO *cs; + + if (!(res= val_str(&str_value))) + return 0; /* Null value */ + cs= res->charset(); + end= (char*) res->ptr()+res->length(); + return cs->strtoll10(res->ptr(), &end, &err_not_used); + } + my_decimal *val_decimal(my_decimal *dec) override; + const Type_handler *type_handler() const override + { return string_type_handler(); } + bool fix_length_and_dec(THD *thd) override; + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_udf_str>(thd, this); } +}; + + +class Item_sum_udf_decimal :public Item_udf_sum +{ +public: + Item_sum_udf_decimal(THD *thd, udf_func *udf_arg): + Item_udf_sum(thd, udf_arg) {} + Item_sum_udf_decimal(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_udf_sum(thd, udf_arg, list) {} + Item_sum_udf_decimal(THD *thd, Item_sum_udf_decimal *item) + :Item_udf_sum(thd, item) {} + String *val_str(String *str) override + { + return VDec(this).to_string_round(str, decimals); + } + double val_real() override + { + return VDec(this).to_double(); + } + longlong val_int() override + { + return VDec(this).to_longlong(unsigned_flag); + } + my_decimal *val_decimal(my_decimal *) override; + const Type_handler *type_handler() const override + { return &type_handler_newdecimal; } + bool fix_length_and_dec(THD *thd) override + { fix_num_length_and_dec(); return FALSE; } + Item *copy_or_same(THD* thd) override; + Item *get_copy(THD *thd) override + { return get_item_copy<Item_sum_udf_decimal>(thd, this); } +}; + +#else /* Dummy functions to get yy_*.cc files compiled */ + +class Item_sum_udf_float :public Item_sum_double +{ + public: + Item_sum_udf_float(THD *thd, udf_func *udf_arg): + Item_sum_double(thd) {} + Item_sum_udf_float(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_sum_double(thd) {} + Item_sum_udf_float(THD *thd, Item_sum_udf_float *item) + :Item_sum_double(thd, item) {} + enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; } + double val_real() { DBUG_ASSERT(fixed()); return 0.0; } + void clear() {} + bool add() { return 0; } + void reset_field() { DBUG_ASSERT(0); }; + void update_field() {} +}; + + +class Item_sum_udf_int :public Item_sum_double +{ +public: + Item_sum_udf_int(THD *thd, udf_func *udf_arg): + Item_sum_double(thd) {} + Item_sum_udf_int(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_sum_double(thd) {} + Item_sum_udf_int(THD *thd, Item_sum_udf_int *item) + :Item_sum_double(thd, item) {} + enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; } + longlong val_int() { DBUG_ASSERT(fixed()); return 0; } + double val_real() { DBUG_ASSERT(fixed()); return 0; } + void clear() {} + bool add() { return 0; } + void reset_field() { DBUG_ASSERT(0); }; + void update_field() {} +}; + + +class Item_sum_udf_decimal :public Item_sum_double +{ + public: + Item_sum_udf_decimal(THD *thd, udf_func *udf_arg): + Item_sum_double(thd) {} + Item_sum_udf_decimal(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_sum_double(thd) {} + Item_sum_udf_decimal(THD *thd, Item_sum_udf_float *item) + :Item_sum_double(thd, item) {} + enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; } + double val_real() { DBUG_ASSERT(fixed()); return 0.0; } + my_decimal *val_decimal(my_decimal *) { DBUG_ASSERT(fixed()); return 0; } + void clear() {} + bool add() { return 0; } + void reset_field() { DBUG_ASSERT(0); }; + void update_field() {} +}; + + +class Item_sum_udf_str :public Item_sum_double +{ +public: + Item_sum_udf_str(THD *thd, udf_func *udf_arg): + Item_sum_double(thd) {} + Item_sum_udf_str(THD *thd, udf_func *udf_arg, List<Item> &list): + Item_sum_double(thd) {} + Item_sum_udf_str(THD *thd, Item_sum_udf_str *item) + :Item_sum_double(thd, item) {} + String *val_str(String *) + { DBUG_ASSERT(fixed()); null_value=1; return 0; } + double val_real() { DBUG_ASSERT(fixed()); null_value=1; return 0.0; } + longlong val_int() { DBUG_ASSERT(fixed()); null_value=1; return 0; } + bool fix_length_and_dec(THD *thd) override + { base_flags|= item_base_t::MAYBE_NULL; max_length=0; return FALSE; } + enum Sumfunctype sum_func () const { return UDF_SUM_FUNC; } + void clear() {} + bool add() { return 0; } + void reset_field() { DBUG_ASSERT(0); }; + void update_field() {} +}; + +#endif /* HAVE_DLOPEN */ + +C_MODE_START +int group_concat_key_cmp_with_distinct(void* arg, const void* key1, + const void* key2); +int group_concat_key_cmp_with_distinct_with_nulls(void* arg, const void* key1, + const void* key2); +int group_concat_key_cmp_with_order(void* arg, const void* key1, + const void* key2); +int group_concat_key_cmp_with_order_with_nulls(void *arg, const void *key1, + const void *key2); +int dump_leaf_key(void* key_arg, + element_count count __attribute__((unused)), + void* item_arg); +C_MODE_END + +class Item_func_group_concat : public Item_sum +{ +protected: + TMP_TABLE_PARAM *tmp_table_param; + String result; + String *separator; + TREE tree_base; + TREE *tree; + size_t tree_len; + Item **ref_pointer_array; + + /** + If DISTINCT is used with this GROUP_CONCAT, this member is used to filter + out duplicates. + @see Item_func_group_concat::setup + @see Item_func_group_concat::add + @see Item_func_group_concat::clear + */ + Unique *unique_filter; + TABLE *table; + ORDER **order; + Name_resolution_context *context; + /** The number of ORDER BY items. */ + uint arg_count_order; + /** The number of selected items, aka the expr list. */ + uint arg_count_field; + uint row_count; + bool distinct; + bool warning_for_row; + bool always_null; + bool force_copy_fields; + /** True if entire result of GROUP_CONCAT has been written to output buffer. */ + bool result_finalized; + /** Limits the rows in the result */ + Item *row_limit; + /** Skips a particular number of rows in from the result*/ + Item *offset_limit; + bool limit_clause; + /* copy of the offset limit */ + ulonglong copy_offset_limit; + /*copy of the row limit */ + ulonglong copy_row_limit; + + /* + Following is 0 normal object and pointer to original one for copy + (to correctly free resources) + */ + Item_func_group_concat *original; + + /* + Used by Item_func_group_concat and Item_func_json_arrayagg. The latter + needs null values but the former doesn't. + */ + bool add(bool exclude_nulls); + + friend int group_concat_key_cmp_with_distinct(void* arg, const void* key1, + const void* key2); + friend int group_concat_key_cmp_with_distinct_with_nulls(void* arg, + const void* key1, + const void* key2); + friend int group_concat_key_cmp_with_order(void* arg, const void* key1, + const void* key2); + friend int group_concat_key_cmp_with_order_with_nulls(void *arg, + const void *key1, const void *key2); + friend int dump_leaf_key(void* key_arg, + element_count count __attribute__((unused)), + void* item_arg); + + bool repack_tree(THD *thd); + + /* + Says whether the function should skip NULL arguments + or add them to the result. + Redefined in JSON_ARRAYAGG. + */ + virtual bool skip_nulls() const { return true; } + virtual String *get_str_from_item(Item *i, String *tmp) + { return i->val_str(tmp); } + virtual String *get_str_from_field(Item *i, Field *f, String *tmp, + const uchar *key, size_t offset) + { return f->val_str(tmp, key + offset); } + virtual void cut_max_length(String *result, + uint old_length, uint max_length) const; +public: + // Methods used by ColumnStore + bool get_distinct() const { return distinct; } + uint get_count_field() const { return arg_count_field; } + uint get_order_field() const { return arg_count_order; } + const String* get_separator() const { return separator; } + ORDER** get_order() const { return order; } + +public: + Item_func_group_concat(THD *thd, Name_resolution_context *context_arg, + bool is_distinct, List<Item> *is_select, + const SQL_I_List<ORDER> &is_order, String *is_separator, + bool limit_clause, Item *row_limit, Item *offset_limit); + + Item_func_group_concat(THD *thd, Item_func_group_concat *item); + ~Item_func_group_concat(); + void cleanup() override; + + enum Sumfunctype sum_func () const override {return GROUP_CONCAT_FUNC;} + LEX_CSTRING func_name_cstring() const override + { + static LEX_CSTRING sum_name= {STRING_WITH_LEN("group_concat(") }; + return sum_name; + } + const Type_handler *type_handler() const override + { + if (too_big_for_varchar()) + return &type_handler_blob; + return &type_handler_varchar; + } + void clear() override; + bool add() override + { + return add(skip_nulls()); + } + void reset_field() override { DBUG_ASSERT(0); } // not used + void update_field() override { DBUG_ASSERT(0); } // not used + bool fix_fields(THD *,Item **) override; + bool setup(THD *thd) override; + void make_unique() override; + double val_real() override + { + int error; + const char *end; + String *res; + if (!(res= val_str(&str_value))) + return 0.0; + end= res->ptr() + res->length(); + return (my_strtod(res->ptr(), (char**) &end, &error)); + } + longlong val_int() override + { + String *res; + char *end_ptr; + int error; + if (!(res= val_str(&str_value))) + return (longlong) 0; + end_ptr= (char*) res->ptr()+ res->length(); + return my_strtoll10(res->ptr(), &end_ptr, &error); + } + my_decimal *val_decimal(my_decimal *decimal_value) override + { + return val_decimal_from_string(decimal_value); + } + bool get_date(THD *thd, MYSQL_TIME *ltime, date_mode_t fuzzydate) override + { + return get_date_from_string(thd, ltime, fuzzydate); + } + String *val_str(String *str) override; + Item *copy_or_same(THD* thd) override; + void no_rows_in_result() override {} + void print(String *str, enum_query_type query_type) override; + bool change_context_processor(void *cntx) override + { context= (Name_resolution_context *)cntx; return FALSE; } + Item *get_copy(THD *thd) override + { return get_item_copy<Item_func_group_concat>(thd, this); } + qsort_cmp2 get_comparator_function_for_distinct(); + qsort_cmp2 get_comparator_function_for_order_by(); + uchar* get_record_pointer(); + uint get_null_bytes(); + +}; + +#endif /* ITEM_SUM_INCLUDED */ |