Questions:
1. Does the inserted table have constraints - especially FK contraints back
to a parent table?
2. Is there anything unusual about the table being inserted such as being
an IOT , partitioned etc?
Tips:
1. Execute your SELECT sql (without the INSERT) and then immediately
execute :
select * from table(dbms_xplan.display_cursor(null,null,'ADVANCED IOSTATS
LAST'))
/
From that output you can grab everything under the OUTLINE section - it's a
big hint and you can add that to your SELECT statement and use it in your
insert.
For example let's say your output under OUTLINE DATA looks something like:
/*+
BEGIN_OUTLINE_DATA
IGNORE_OPTIM_EMBEDDED_HINTS
OPTIMIZER_FEATURES_ENABLE('12.1.0.2')
DB_VERSION('12.1.0.2')
OPT_PARAM('_optim_peek_user_binds' 'false')
OPT_PARAM('optimizer_dynamic_sampling' 0)
OPT_PARAM('_bloom_filter_enabled' 'false')
OPT_PARAM('_optimizer_use_feedback' 'false')
OPT_PARAM('_px_adaptive_dist_method' 'off')
OPT_PARAM('_optimizer_dsdir_usage_control' 0)
OPT_PARAM('_optimizer_adaptive_plans' 'false')
OPT_PARAM('_optimizer_strans_adaptive_pruning' 'false')
OPT_PARAM('_optimizer_gather_feedback' 'false')
OPT_PARAM('_optimizer_aggr_groupby_elim' 'false')
OPT_PARAM('_optimizer_reduce_groupby_key' 'false')
OPT_PARAM('_optimizer_nlj_hj_adaptive_join' 'false')
OPT_PARAM('_fix_control' '20355502:8')
ALL_ROWS
OUTLINE_LEAF(@"SEL$1")
FULL(@"SEL$1" "N"@"SEL$1")
END_OUTLINE_DATA
*/
Then your INSERT would become:
INSERT into my_table (col1, col2, col3, colN)
SELECT /*+
BEGIN_OUTLINE_DATA
IGNORE_OPTIM_EMBEDDED_HINTS
OPTIMIZER_FEATURES_ENABLE('12.1.0.2')
DB_VERSION('12.1.0.2')
OPT_PARAM('_optim_peek_user_binds' 'false')
OPT_PARAM('optimizer_dynamic_sampling' 0)
OPT_PARAM('_bloom_filter_enabled' 'false')
OPT_PARAM('_optimizer_use_feedback' 'false')
OPT_PARAM('_px_adaptive_dist_method' 'off')
OPT_PARAM('_optimizer_dsdir_usage_control' 0)
OPT_PARAM('_optimizer_adaptive_plans' 'false')
OPT_PARAM('_optimizer_strans_adaptive_pruning' 'false')
OPT_PARAM('_optimizer_gather_feedback' 'false')
OPT_PARAM('_optimizer_aggr_groupby_elim' 'false')
OPT_PARAM('_optimizer_reduce_groupby_key' 'false')
OPT_PARAM('_optimizer_nlj_hj_adaptive_join' 'false')
OPT_PARAM('_fix_control' '20355502:8')
ALL_ROWS
OUTLINE_LEAF(@"SEL$1")
FULL(@"SEL$1" "N"@"SEL$1")
END_OUTLINE_DATA
*/
col1, col2, col3, colN from my_other_table;
HTH
Chris
On Fri, Apr 27, 2018 at 10:50 AM, Sheehan, Jeremy <JEREMY.SHEEHAN@xxxxxxx>
wrote:
Hello Gurus,
Oracle 12.1.0.2
AIX 7.1
I have a query that runs fairly well. Takes about 8 minutes to run,
nothing terrible about it (no huge FTS, joins seem to be in place
correctly). When I try to do an insert into TABLE as SELECT, it picks a
completely different execution plan and never finishes. The really odd
thing is that it works great when using CTAS or initial creation of a MV.
Any suggestion on how I can have the optimizer not use a specific
execution plan or any session level parameters that would have it use a
different execution plan?
Thanks in advance!
Jeremy
