Code review comment for lp:~dingqi-lxb/percona-server/5.5_log_queries_in_memory

1. Please add patch name to the "patches/series" file
2. About innodb_trx_id. Please look to two following cases:
 * log_slow_verbosity doesn't set "innodb"
 * query doesn't use the InnoDB
In first case slow query log will has no information about InnoDB
In second case slow query will have line "# No InnoDB statistics available for this query\n"
In this two cases innodb_trx_id will be incorrect, and you can't use and setup it.

Please handle variable innodb_was_used correctly (at least for innodb_trx_id)

3. Following is very, very bad:
+ if (general_query)
+ {
....
+ }
+ else
+ {
+ this->general_query= "NULL";
+ this->general_query_len= 5;
+ }
You are break SQL semantic. For example query:
SELECT * FROM INSFORMATION_SCHEMA.I_S_SLOW_LOG WHERE QUERY IS NULL
or any join will not work correctly.
You are break SQL language semantic by string "NULL" instead of NULL

Same for Schema.

4. I_S_SLOW_LOG not very good name. Why SLOW_LOG bad?

5. Please add documentation to the doc/

6. Sleep in the test file - bad idea. Please replace this by debug variable query_exec_time.

7. Please add tests to sys_vars suite for the all added variables.

Please fix this, and I will review again.