Questions On Parallel Degree For SQL Statements
(Doc ID 2643108.1)
Last updated on APRIL 17, 2023
Applies to:Oracle Database - Enterprise Edition - Version 188.8.131.52 and later
Information in this document applies to any platform.
- High load is associated with stats jobs for each schema that run from the scheduler
- Job is running at the same time as the staggering of start times is not large enough
- Each schema has a job to connect full stats as follows:
begin dbms_stats.gather_schema_stats (ownname => '',
method_opt => 'for all columns size auto',
estimate_percent => 100,
cascade => true,
options => 'gather'); end;
- There are many queries in AWR showing following:
select /*+ parallel_index(t, "_IDX1", 384) dbms_stats cursor_sharing_exact use_weak_name_resl dynamic_sampling(0) no_monitoring xmlindex_sel_idx_tbl opt_param('optimizer_inmemory_aware' 'false') no_substrb_pad no_expand index_ffs(t, "_IDX1") */ count(*) as nrw, count(distinct sys_op_lbid(364661, 'L', t.rowid)) as nlb, count(distinct "SYS_NC00015$") as ndk, sys_op_countchg(substrb(t.rowid, 1, 15), 1) as clf from...
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