MySQL  8.0.16
Source Code Documentation
object_table.h
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22 
23 #ifndef DD__OBJECT_TABLE_INCLUDED
24 #define DD__OBJECT_TABLE_INCLUDED
25 
26 #include "my_inttypes.h"
27 #include "sql/dd/string_type.h" // dd::String_type
28 
29 class THD;
30 
31 namespace dd {
32 
33 ///////////////////////////////////////////////////////////////////////////
34 
35 class Object_table_definition;
36 class Properties;
37 
38 ///////////////////////////////////////////////////////////////////////////
39 
40 /**
41  This class represents all data dictionary table like mysql.tables,
42  mysql.columns and more. This is the base class of all the classes
43  defined in sql/dd/impl/tables/ headers. This class is also the base
44  class of tables requested by the DDSE and by plugins.
45 
46  The server code should contain a Object_table subclass for each DD table
47  which is a target table for at least one of the supported DD versions (i.e.,
48  the DD versions from which this server can upgrade). So even if a previous
49  DD version stops using a DD table, the later servers which can upgrade need
50  to keep the Object_table subclass for that table. The motivation for that
51  is to be able to recognize the table, and to be able to remove it.
52 
53  Instances of this class will contain one or two table definitions, depending
54  on the context:
55 
56  - The actual table definition reflects the persistently stored DD table,
57  i.e., what is reflected in the persistently stored mete data.
58  - The target table definition reflects the DD table which the server
59  is using during normal operation.
60 
61  If the actual DD version is different from the target DD version, upgrade
62  is required. The actual table definition is used only in situations where
63  we have an upgrade or downgrade.
64 
65  @note This class may be inherited along different paths
66  for some subclasses due to the diamond shaped
67  inheritance hierarchy; thus, direct subclasses
68  must inherit this class virtually.
69 */
70 
71 class Object_table {
72  public:
73  /**
74  Allocate a new Object_table instance on the heap.
75 
76  The new instance has the predefined options that all DD tables share:
77 
78  ENGINE=INNODB
79  DEFAULT CHARSET=utf8
80  COLLATE=utf8_bin
81  ROW_FORMAT=DYNAMIC
82  STATS_PERSISTENT=0
83  TABLESPACE=mysql
84 
85  @note The object is owned by the caller.
86 
87  @returns pointer to new Object_table instance.
88  */
90 
91  /**
92  Get the table name used by the target definition for the dictionary table.
93 
94  @return table name.
95  */
96  virtual const String_type &name() const = 0;
97 
98  /**
99  Get the target definition for the dictionary table.
100 
101  @note There are const and non-const variants.
102 
103  @return Pointer to the definition of the table.
104  */
106 
107  virtual const Object_table_definition *target_table_definition() const = 0;
108 
109  /**
110  Mark the target definition for the dictionary table as abandoned.
111 
112  @param last_dd_version Last version where this object table was used.
113  */
114  virtual void set_abandoned(uint last_dd_version) const = 0;
115 
116  /**
117  Check if the dictionary table is abandoned.
118 
119  @return true if the table is abandoned.
120  */
121  virtual bool is_abandoned() const = 0;
122 
123  /**
124  Get the actual definition for the dictionary table.
125 
126  The actual definition is the definition which is used by a DD table
127  which is stored persistently. Normally, for an ordinary running server,
128  the actual table definitions are equal to the target table definitions.
129  In an upgrade context, they may differ.
130 
131  @return Pointer to the definition of the table.
132  */
133  virtual const Object_table_definition *actual_table_definition() const = 0;
134 
135  /**
136  Set the actual definition for the dictionary table.
137 
138  @param table_def_properties Actual table definition represented as
139  a set of properties.
140 
141  @return false if no error.
142  */
143  virtual bool set_actual_table_definition(
144  const Properties &table_def_properties) const = 0;
145 
146  /**
147  Get the field ordinal position in the object table.
148 
149  @return Integer ordinal position.
150  */
151  virtual int field_number(const String_type &field_label) const = 0;
152 
153  /**
154  Execute low level code for populating the table.
155 
156  @return Boolean operation outcome, false if success.
157  */
158  virtual bool populate(THD *thd) const = 0;
159 
160  /**
161  Check if the table should be hidden.
162 
163  Most of Object tables (alias DD tables) are hidden from users,
164  but some of them are expected to be visible (not hidden) to user and be
165  able to update them, e.g., innodb_index_stats/innodb_table_stats.
166 
167  @returns true if the table should be hidden.
168  */
169  virtual bool is_hidden() const = 0;
170 
171  /**
172  Mark the dictionary table as hidden or visible.
173 
174  @param hidden Set to 'true' if the table should be hidden.
175  */
176  virtual void set_hidden(bool hidden) = 0;
177 
178  public:
179  virtual ~Object_table() {}
180 };
181 
182 ///////////////////////////////////////////////////////////////////////////
183 
184 } // namespace dd
185 
186 #endif // DD__OBJECT_TABLE_INCLUDED
Some integer typedefs for easier portability.
Char_string_template< String_type_allocator > String_type
Definition: string_type.h:50
virtual void set_hidden(bool hidden)=0
Mark the dictionary table as hidden or visible.
virtual void set_abandoned(uint last_dd_version) const =0
Mark the target definition for the dictionary table as abandoned.
virtual ~Object_table()
Definition: object_table.h:179
The purpose of this interface is to enable retrieving the SQL statements necessary to create and popu...
Definition: object_table_definition.h:46
virtual Object_table_definition * target_table_definition()=0
Get the target definition for the dictionary table.
virtual bool is_abandoned() const =0
Check if the dictionary table is abandoned.
unsigned int uint
Definition: uca-dump.cc:29
The Properties class defines an interface for storing key=value pairs, where both key and value may b...
Definition: properties.h:73
virtual int field_number(const String_type &field_label) const =0
Get the field ordinal position in the object table.
virtual bool is_hidden() const =0
Check if the table should be hidden.
This class represents all data dictionary table like mysql.tables, mysql.columns and more...
Definition: object_table.h:71
The version of the current data dictionary table definitions.
Definition: dictionary_client.h:39
virtual const String_type & name() const =0
Get the table name used by the target definition for the dictionary table.
virtual bool populate(THD *thd) const =0
Execute low level code for populating the table.
virtual bool set_actual_table_definition(const Properties &table_def_properties) const =0
Set the actual definition for the dictionary table.
virtual const Object_table_definition * actual_table_definition() const =0
Get the actual definition for the dictionary table.
For each client connection we create a separate thread with THD serving as a thread/connection descri...
Definition: sql_class.h:776
static Object_table * create_object_table()
Allocate a new Object_table instance on the heap.
Definition: object_table_impl.cc:86