Investigation for query perfomance in redshift
1) Look log-table(svl_qlog) get qery id
select query, elapsed, substring
from svl_qlog
order by query
desc limit 10;
2) pass qery id in summary-table (svl_query_summary )
select query, stm, seg, step, maxtime, rows, label, is_diskbased, workmem, rows_pre_filter
from svl_query_summary where query = <queryid> order by stm, seg, step;
3)pass query if to get time of excution for query time-table(elapsed_time)
select * from svl_query_report where query = <queryid> order by segment, step,
elapsed_time, rows;