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- Committer: Brian Aker
- Date: 2009-01-28 01:12:41 UTC
- Revision ID: brian@tangent.org-20090128011241-w309ibv1yeza84cp
Dead variable array removal for statement based. (Thank god I got something
done today)
done today)
- files modified:
- drizzled/function/get_user_var.cc
added
removed
drizzled/function/get_user_var.cc
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return (var_entry->val_int(&null_value));
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}
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/**
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Get variable by name and, if necessary, put the record of variable
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use into the binary log.
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When a user variable is invoked from an update query (INSERT, UPDATE etc),
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stores this variable and its value in session->user_var_events, so that it can be
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written to the binlog (will be written just before the query is written, see
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log.cc).
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@param session Current thread
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@param name Variable name
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@param[out] out_entry variable structure or NULL. The pointer is set
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regardless of whether function succeeded or not.
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@retval
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0 OK
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@retval
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1 Failed to put appropriate record into binary log
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*/
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static int get_var_with_binlog(Session *session, enum_sql_command sql_command,
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LEX_STRING &name, user_var_entry **out_entry)
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{
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BINLOG_USER_VAR_EVENT *user_var_event;
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user_var_entry *var_entry;
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var_entry= get_variable(&session->user_vars, name, 0);
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/*
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Any reference to user-defined variable which is done from stored
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function or trigger affects their execution and the execution of the
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calling statement. We must log all such variables even if they are
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not involved in table-updating statements.
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*/
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if (!(opt_bin_log && is_update_query(sql_command)))
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{
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*out_entry= var_entry;
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return 0;
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}
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if (!var_entry)
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{
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/*
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If the variable does not exist, it's NULL, but we want to create it so
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that it gets into the binlog (if it didn't, the slave could be
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influenced by a variable of the same name previously set by another
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thread).
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We create it like if it had been explicitly set with SET before.
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The 'new' mimics what sql_yacc.yy does when 'SET @a=10;'.
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sql_set_variables() is what is called from 'case SQLCOM_SET_OPTION'
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in dispatch_command()). Instead of building a one-element list to pass to
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sql_set_variables(), we could instead manually call check() and update();
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this would save memory and time; but calling sql_set_variables() makes
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one unique place to maintain (sql_set_variables()).
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Manipulation with lex is necessary since free_underlaid_joins
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is going to release memory belonging to the main query.
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*/
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List<set_var_base> tmp_var_list;
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LEX *sav_lex= session->lex, lex_tmp;
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session->lex= &lex_tmp;
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lex_start(session);
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tmp_var_list.push_back(new set_var_user(new Item_func_set_user_var(name,
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new Item_null())));
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/* Create the variable */
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if (sql_set_variables(session, &tmp_var_list))
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{
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session->lex= sav_lex;
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goto err;
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}
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session->lex= sav_lex;
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if (!(var_entry= get_variable(&session->user_vars, name, 0)))
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goto err;
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}
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else if (var_entry->used_query_id == session->query_id)
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{
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/*
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If this variable was already stored in user_var_events by this query
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(because it's used in more than one place in the query), don't store
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it.
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*/
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*out_entry= var_entry;
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return 0;
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}
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uint32_t size;
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/*
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First we need to store value of var_entry, when the next situation
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appears:
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> set @a:=1;
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> insert into t1 values (@a), (@a:=@a+1), (@a:=@a+1);
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We have to write to binlog value @a= 1.
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We allocate the user_var_event on user_var_events_alloc pool, not on
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the this-statement-execution pool because in SPs user_var_event objects
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may need to be valid after current [SP] statement execution pool is
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destroyed.
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*/
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size= ALIGN_SIZE(sizeof(BINLOG_USER_VAR_EVENT)) + var_entry->length;
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if (!(user_var_event= (BINLOG_USER_VAR_EVENT *)
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alloc_root(session->user_var_events_alloc, size)))
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goto err;
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user_var_event->value= (char*) user_var_event +
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ALIGN_SIZE(sizeof(BINLOG_USER_VAR_EVENT));
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user_var_event->user_var_event= var_entry;
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user_var_event->type= var_entry->type;
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user_var_event->charset_number= var_entry->collation.collation->number;
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if (!var_entry->value)
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{
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/* NULL value*/
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user_var_event->length= 0;
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user_var_event->value= 0;
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}
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else
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{
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user_var_event->length= var_entry->length;
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memcpy(user_var_event->value, var_entry->value,
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var_entry->length);
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}
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/* Mark that this variable has been used by this query */
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var_entry->used_query_id= session->query_id;
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if (insert_dynamic(&session->user_var_events, (unsigned char*) &user_var_event))
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goto err;
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*out_entry= var_entry;
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return 0;
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err:
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*out_entry= var_entry;
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return 1;
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}
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void Item_func_get_user_var::fix_length_and_dec()
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{
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Session *session=current_session;
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int error;
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maybe_null=1;
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decimals=NOT_FIXED_DEC;
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max_length=MAX_BLOB_WIDTH;
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error= get_var_with_binlog(session, session->lex->sql_command, name, &var_entry);
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var_entry= get_variable(&session->user_vars, name, 0);
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/*
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If the variable didn't exist it has been created as a STRING-type.
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