MySQL 9.0.0
Source Code Documentation
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When the query has window functions, an outer node named "windowing" is added: query_block: { select_id: 1, windowing: { windows: [ ... list of all windows' details ... ], nested_loop: [ ... ]. More...
Public Member Functions | |
window_ctx (context *parent_arg) | |
Public Member Functions inherited from opt_explain_json_namespace::join_ctx | |
join_ctx (enum_parsing_context type_arg, const char *name_arg, context *parent_arg) | |
bool | add_join_tab (joinable_ctx *ctx) override |
Add a CTX_QEP_TAB node to a CTX_JOIN node. More... | |
void | set_sort (sort_ctx *ctx) override |
Set nested ORDER BY/GROUP BY/DISTINCT node to ctx . More... | |
void | set_window (window_ctx *ctx) override |
Set nested WINDOW node to ctx . More... | |
qep_row * | entry () override |
bool | find_and_set_derived (context *subquery) override |
Associate a CTX_DERIVED node with its CTX_QEP_TAB node. More... | |
bool | add_subquery (subquery_list_enum subquery_type, subquery_ctx *ctx) override |
Append a subquery node to the specified list of the unit node. More... | |
bool | format_nested_loop (Opt_trace_context *json) override |
Format nested loop join subtree (if any) to JSON formatter. More... | |
size_t | id (bool hide) override |
Analogue of the "id" column in the traditional EXPLAIN output. More... | |
bool | cacheable () override |
bool | dependent () override |
int | add_where_subquery (subquery_ctx *ctx, Query_expression *subquery) override |
Associate WHERE subqueries of given context and unit with this object. More... | |
Public Member Functions inherited from opt_explain_json_namespace::unit_ctx | |
unit_ctx (enum_parsing_context type_arg, const char *name_arg, context *parent_arg) | |
bool | has_no_subqueries () const |
Helper function to distinguish subquery-less nodes. More... | |
bool | format_query_expression (Opt_trace_context *json) override |
Helper function to format output for HAVING, ORDER/GROUP BY subqueries. More... | |
Public Member Functions inherited from opt_explain_json_namespace::context | |
context (enum_parsing_context type_arg, const char *name_arg, context *parent_arg) | |
virtual | ~context ()=default |
virtual bool | format (Opt_trace_context *json) |
Pass the node with its child nodes to a JSON formatter. More... | |
bool | is_query_block () const |
virtual enum_mod_type | get_mod_type () |
virtual void | set_child (context *) |
Associate a child node with this node. More... | |
virtual void | set_setop_result (setop_result_ctx *) |
associate CTX_UNION_RESULT node with CTX_UNION node More... | |
virtual bool | add_query_spec (context *ctx) |
Add a query specification node to the CTX_UNION node. More... | |
virtual bool | format_derived (Opt_trace_context *) |
Helper function to format output for derived subquery if any. More... | |
virtual bool | format_where (Opt_trace_context *) |
Helper function to format output for associated WHERE subqueries if any. More... | |
Public Member Functions inherited from Explain_context | |
Explain_context (enum_parsing_context type_arg) | |
Public Member Functions inherited from qep_row | |
qep_row () | |
virtual | ~qep_row ()=default |
void | cleanup () |
virtual void | register_where_subquery (Query_expression *subquery) |
Remember a subquery's unit. More... | |
void | format_extra (Opt_trace_object *obj) |
Protected Member Functions | |
const char * | get_cost_tag () override |
Protected Member Functions inherited from opt_explain_json_namespace::join_ctx | |
bool | format_body_inner (Opt_trace_context *json, Opt_trace_object *obj) |
Private Member Functions | |
bool | format_body (Opt_trace_context *json, Opt_trace_object *obj) override |
Format JSON object body. More... | |
Additional Inherited Members | |
Public Attributes inherited from opt_explain_json_namespace::context | |
context * | parent |
link to parent node or NULL More... | |
Public Attributes inherited from Explain_context | |
enum_parsing_context | type |
type tag More... | |
Public Attributes inherited from qep_row | |
column< uint > | col_id |
"id" column: seq. number of SELECT within the query More... | |
column< enum_explain_type > | col_select_type |
"select_type" column More... | |
mem_root_str | col_table_name |
"table" to which the row of output refers More... | |
List< const char > | col_partitions |
"partitions" column More... | |
mem_root_str | col_join_type |
"type" column, see join_type_str array More... | |
List< const char > | col_possible_keys |
"possible_keys": comma-separated list More... | |
mem_root_str | col_key |
"key" column: index that is actually decided to use More... | |
mem_root_str | col_key_len |
"key_length" column: length of the "key" above More... | |
List< const char > | col_ref |
"ref":columns/constants which are compared to "key" More... | |
column< float > | col_filtered |
"filtered": % of rows filtered by condition More... | |
List< extra > | col_extra |
"extra" column (traditional) or property list More... | |
mem_root_str | col_message |
replaces "Extra" column if not empty More... | |
mem_root_str | col_attached_condition |
former "Using where" More... | |
column< ulonglong > | col_rows |
"rows": estimated number of examined table rows per single scan More... | |
column< ulonglong > | col_prefix_rows |
"rows": estimated number of examined table rows per query More... | |
column< double > | col_read_cost |
Time to read the table. More... | |
column< double > | col_prefix_cost |
Cost of the partial join including this table. More... | |
column< double > | col_cond_cost |
Cost of evaluating conditions on this table per query. More... | |
mem_root_str | col_data_size_query |
Size of data expected to be read per query. More... | |
List< const char > | col_used_columns |
List of used columns. More... | |
List< const char > | col_partial_update_columns |
List of columns that can be updated using partial update. More... | |
uint | query_block_id |
query block id for materialized subqueries More... | |
List< opt_explain_json_namespace::context > | derived_from |
List of "derived" subquery trees. More... | |
List< const char > | col_key_parts |
used parts of the key More... | |
bool | is_dependent |
bool | is_cacheable |
bool | using_temporary |
enum_mod_type | mod_type |
bool | is_materialized_from_subquery |
uint | derived_clone_id |
If a clone of a materialized derived table, this is the ID of the first underlying query block of the first materialized derived table. More... | |
List< Window > * | m_windows |
Windows to describe in this node. More... | |
Protected Attributes inherited from opt_explain_json_namespace::join_ctx | |
List< joinable_ctx > | join_tabs |
hosted JOIN_TAB nodes More... | |
sort_ctx * | sort |
window_ctx * | window |
Protected Attributes inherited from opt_explain_json_namespace::context | |
const char * | name |
When the query has window functions, an outer node named "windowing" is added: query_block: { select_id: 1, windowing: { windows: [ ... list of all windows' details ... ], nested_loop: [ ... ].
Due to this "outer-node" layout, the implementation of window_ctx is similar to that of sort_ctx. Except that while it makes sense to describe to the user the "subqueries included in ORDER BY", it doesn't for "subqueries included in the window function's arguments" (the window function belongs to the SELECT list or ORDER BY: so does the subquery, simply), so there is no window_with_subqueries_ctx.
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inline |
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inlineoverrideprivatevirtual |
Format JSON object body.
json | Formatter |
obj | Object of this body |
false | Ok |
true | Error |
Reimplemented from opt_explain_json_namespace::join_ctx.
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inlineoverrideprotectedvirtual |
Reimplemented from opt_explain_json_namespace::join_ctx.