diff options
Diffstat (limited to 'sql/opt_trace.h')
| -rw-r--r-- | sql/opt_trace.h | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/sql/opt_trace.h b/sql/opt_trace.h index 101fb5f707e..c6583cdab80 100644 --- a/sql/opt_trace.h +++ b/sql/opt_trace.h @@ -69,10 +69,34 @@ struct Opt_trace_info @param query query @param length query's length @param charset charset which was used to encode this query + + @detail + == Lifecycle == + The trace is created before the Name Resolution phase. Reasons: + 1. This way, we can have one place where we start the trace for all kinds of + queries. If we tried to start tracing right before query optimization + starts, we would have to construct Opt_trace_start object in many + places: one for SELECT, for UPDATE, for DELETE, etc. + + 2. Privilege checking code may notify the trace that the user doesn't have + enough permissions to perform tracing. The trace must exist to receive + the notication. See missing_privilege() and the opt_trace_disable_if_... + functions below for details. + + == Handling Query Errors == + The trace is kept when query error occurs, except for the case when + nothing [meaningful] was traced. The second part is necessary for mtr to + produce the same output with and without --ps-protocol. If there is an + error on prepare phase, then: + - In --ps-protocol: PREPARE command produces no trace. The EXECUTE + command is not run. The trace is not generated at all. + - Regular SQL query: should also NOT produce any trace to match the above. + This is handled by trace_heading_done() and clean_empty_trace(). */ -class Opt_trace_start { +class Opt_trace_start +{ public: Opt_trace_start(THD *thd_arg, TABLE_LIST *tbl, enum enum_sql_command sql_command, @@ -82,8 +106,17 @@ class Opt_trace_start { const CHARSET_INFO *query_charset); ~Opt_trace_start(); + void trace_heading_done(); + void clean_empty_trace(); private: Opt_trace_context *const ctx; + + /* Number of bytes written to the trace after the heading was written/ */ + size_t trace_heading_size; + + /* If true, trace should be removed (See Handling Query Errors above) */ + bool clean_me= false; + /* True: the query will be traced False: otherwise @@ -102,6 +135,9 @@ class Opt_trace_start { void opt_trace_print_expanded_query(THD *thd, SELECT_LEX *select_lex, Json_writer_object *trace_object); +void opt_trace_print_expanded_union(THD *thd, SELECT_LEX_UNIT *unit, + Json_writer_object *writer); + void add_table_scan_values_to_trace(THD *thd, JOIN_TAB *tab); void trace_plan_prefix(JOIN *join, uint idx, table_map join_tables); void print_final_join_order(JOIN *join); |