[MDEV-407] Print EXPLAIN [ANALYZE] in the slow query log - Jira

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SHOW EXPLAIN allows to produce EXPLAIN during the query execution. We are now able to save it in the slow query log.

The user interface is as follows:

"explain" is a new flag in log-slow-verbosity argument:

[mysqld]

...

log-slow-verbosity=query_plan,explain

The output is printed into slow query log like this:

# User@Host: root[root] @ localhost []

# Thread_id: 2  Schema: j4  QC_hit: No

# Query_time: 0.000629  Lock_time: 0.000202  Rows_sent: 3  Rows_examined: 3

# Full_scan: Yes  Full_join: No  Tmp_table: No  Tmp_table_on_disk: No

# Filesort: No  Filesort_on_disk: No  Merge_passes: 0

## <explain>

##   id select_type     table   type    possible_keys   key     key_len ref     rows    Extra

##   1  SIMPLE  t1      ALL     NULL    NULL    NULL    NULL    3       Using where

## </explain>

SET timestamp=1381828772;

select * from t1 where a between 1 and 3333;

is blocked by

MDEV-3798 Add EXPLAIN for UPDATE/DELETE (mwl #51)

relates to

MDEV-5045 Server crashes in QPF_query::print_explain with log_slow_verbosity='query_plan,explain'

MDEV-5060 Server crashes on EXPLAIN EXTENDED or EXPLAIN PARTITIONS with explain in slow_log

MDEV-5067 Valgrind warnings (Invalid read) in QPF_table_access::print_explain / String::append on a SELECT sq with DISTINCT

MDEV-5106 Server crashes in Explain_union::print_explain on ER_TOO_BIG_SELECT with explain in slow log

MDEV-5117 Explain for a query executed as a PS is not written into the slow log

MDEV-5118 Explain output for SHOW EXPLAIN in the slow log looks useless

MDEV-5125 Test sys_vars.log_slow_verbosity_basic fails on 10.0-base-explain-slowquerylog tree

MDEV-6388 ANALYZE $stmt output in the slow query log

MDEV-406 ANALYZE $stmt

(5 relates to)

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