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authorGalina Shalygina <galashalygina@gmail.com>2016-05-08 23:04:41 +0300
committerGalina Shalygina <galashalygina@gmail.com>2016-05-08 23:04:41 +0300
commitbe1d06c8a5f843e775374e5ec148aaee56970bdc (patch)
treebd7a95e771ca3b405583dccab8b468dd6fb4509f /sql/sql_window.h
parente09b1f2a226bf2763b211f74908a6486b83ebed1 (diff)
downloadmariadb-git-be1d06c8a5f843e775374e5ec148aaee56970bdc.tar.gz
Merge branch '10.2' into 10.2-mdev9864
Diffstat (limited to 'sql/sql_window.h')
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diff --git a/sql/sql_window.h b/sql/sql_window.h
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+
+#ifndef SQL_WINDOW_INCLUDED
+#define SQL_WINDOW_INCLUDED
+
+#include "my_global.h"
+#include "item.h"
+#include "filesort.h"
+#include "records.h"
+
+class Item_window_func;
+
+/*
+ Window functions module.
+
+ Each instance of window function has its own element in SELECT_LEX::window_specs.
+*/
+
+
+class Window_frame_bound : public Sql_alloc
+{
+
+public:
+
+ enum Bound_precedence_type
+ {
+ PRECEDING,
+ CURRENT, // Used for CURRENT ROW window frame bounds
+ FOLLOWING
+ };
+
+ Bound_precedence_type precedence_type;
+
+
+ /*
+ For UNBOUNDED PRECEDING / UNBOUNDED FOLLOWING window frame bounds
+ precedence type is seto to PRECEDING / FOLLOWING and
+ offset is set to NULL.
+ The offset is not meaningful with precedence type CURRENT
+ */
+ Item *offset;
+
+ Window_frame_bound(Bound_precedence_type prec_type,
+ Item *offset_val)
+ : precedence_type(prec_type), offset(offset_val) {}
+
+ bool is_unbounded() { return offset == NULL; }
+
+};
+
+
+class Window_frame : public Sql_alloc
+{
+
+public:
+
+ enum Frame_units
+ {
+ UNITS_ROWS,
+ UNITS_RANGE
+ };
+
+ enum Frame_exclusion
+ {
+ EXCL_NONE,
+ EXCL_CURRENT_ROW,
+ EXCL_GROUP,
+ EXCL_TIES
+ };
+
+ Frame_units units;
+
+ Window_frame_bound *top_bound;
+
+ Window_frame_bound *bottom_bound;
+
+ Frame_exclusion exclusion;
+
+ Window_frame(Frame_units win_frame_units,
+ Window_frame_bound *win_frame_top_bound,
+ Window_frame_bound *win_frame_bottom_bound,
+ Frame_exclusion win_frame_exclusion)
+ : units(win_frame_units), top_bound(win_frame_top_bound),
+ bottom_bound(win_frame_bottom_bound), exclusion(win_frame_exclusion) {}
+
+ bool check_frame_bounds();
+
+};
+
+class Window_spec : public Sql_alloc
+{
+ bool window_names_are_checked;
+ public:
+ virtual ~Window_spec() {}
+
+ LEX_STRING *window_ref;
+
+ SQL_I_List<ORDER> *partition_list;
+
+ SQL_I_List<ORDER> *order_list;
+
+ Window_frame *window_frame;
+
+ Window_spec *referenced_win_spec;
+
+ Window_spec(LEX_STRING *win_ref,
+ SQL_I_List<ORDER> *part_list,
+ SQL_I_List<ORDER> *ord_list,
+ Window_frame *win_frame)
+ : window_names_are_checked(false), window_ref(win_ref),
+ partition_list(part_list), order_list(ord_list),
+ window_frame(win_frame), referenced_win_spec(NULL) {}
+
+ virtual char *name() { return NULL; }
+
+ bool check_window_names(List_iterator_fast<Window_spec> &it);
+
+ char *window_reference() { return window_ref ? window_ref->str : NULL; }
+
+ void join_partition_and_order_lists()
+ {
+ *(partition_list->next)= order_list->first;
+ }
+
+ void disjoin_partition_and_order_lists()
+ {
+ *(partition_list->next)= NULL;
+ }
+};
+
+class Window_def : public Window_spec
+{
+ public:
+
+ LEX_STRING *window_name;
+
+ Window_def(LEX_STRING *win_name,
+ LEX_STRING *win_ref,
+ SQL_I_List<ORDER> *part_list,
+ SQL_I_List<ORDER> *ord_list,
+ Window_frame *win_frame)
+ : Window_spec(win_ref, part_list, ord_list, win_frame),
+ window_name(win_name) {}
+
+ char *name() { return window_name->str; }
+
+};
+
+int setup_windows(THD *thd, Ref_ptr_array ref_pointer_array, TABLE_LIST *tables,
+ List<Item> &fields, List<Item> &all_fields,
+ List<Window_spec> &win_specs, List<Item_window_func> &win_funcs);
+
+
+//////////////////////////////////////////////////////////////////////////////
+// Classes that make window functions computation a part of SELECT's query plan
+//////////////////////////////////////////////////////////////////////////////
+
+typedef bool (*window_compute_func_t)(Item_window_func *item_win,
+ TABLE *tbl, READ_RECORD *info);
+
+/*
+ This handles computation of one window function.
+
+ Currently, we make a spearate filesort() call for each window function.
+*/
+
+class Window_func_runner : public Sql_alloc
+{
+ Item_window_func *win_func;
+
+ /* The function to use for computation*/
+ window_compute_func_t compute_func;
+
+public:
+ Window_func_runner(Item_window_func *win_func_arg) :
+ win_func(win_func_arg)
+ {}
+
+ // Set things up. Create filesort structures, etc
+ bool setup(THD *thd);
+
+ // This sorts and runs the window function.
+ bool exec(TABLE *tbl, SORT_INFO *filesort_result);
+};
+
+
+/*
+ Represents a group of window functions that require the same sorting of
+ rows and so share the filesort() call.
+
+*/
+
+class Window_funcs_sort : public Sql_alloc
+{
+ List<Window_func_runner> runners;
+
+ /* Window functions can be computed over this sorting */
+ Filesort *filesort;
+public:
+ bool setup(THD *thd, SQL_SELECT *sel, List_iterator<Item_window_func> &it);
+ bool exec(JOIN *join);
+ void cleanup() { delete filesort; }
+
+ friend class Window_funcs_computation;
+};
+
+
+struct st_join_table;
+class Explain_aggr_window_funcs;
+/*
+ This is a "window function computation phase": a single object of this class
+ takes care of computing all window functions in a SELECT.
+
+ - JOIN optimizer is exected to call setup() during query optimization.
+ - JOIN::exec() should call exec() once it has collected join output in a
+ temporary table.
+*/
+
+class Window_funcs_computation : public Sql_alloc
+{
+ List<Window_funcs_sort> win_func_sorts;
+public:
+ bool setup(THD *thd, List<Item_window_func> *window_funcs, st_join_table *tab);
+ bool exec(JOIN *join);
+
+ Explain_aggr_window_funcs *save_explain_plan(MEM_ROOT *mem_root, bool is_analyze);
+ void cleanup();
+};
+
+
+#endif /* SQL_WINDOW_INCLUDED */