HAWQ-1122. Add ORCA optimizer GUC optimizer_parallel_union for parallel append (#977)
This GUC is disabled by default. Currently, when users run an `UNION ALL` query, such as ```sql SELECT a FROM foo UNION ALL SELECT b FROM bar ```, GPDB will parallelize the execution across all the segments, but the table scans on `foo` and `bar` are not executed parallel. With this GUC enabled, we add redistribution motion node under APPEND(UNION) operator, which makes all the children of APPEND(UNION) operator execute in parallel in every segment. This is cherry-picked from greenplum-db/gpdb@86e49e51d39ed0d252cbf6a79c2fc62e36a4e307 Project: http://git-wip-us.apache.org/repos/asf/incubator-hawq/repo Commit: http://git-wip-us.apache.org/repos/asf/incubator-hawq/commit/e7bba170 Tree: http://git-wip-us.apache.org/repos/asf/incubator-hawq/tree/e7bba170 Diff: http://git-wip-us.apache.org/repos/asf/incubator-hawq/diff/e7bba170 Branch: refs/heads/master Commit: e7bba17080139dd1f20d9d875947b62a2d543082 Parents: f0d891f Author: Haisheng Yuan <hy...@pivotal.io> Authored: Wed Jul 27 19:03:32 2016 -0500 Committer: rlei <r...@pivotal.io> Committed: Fri Oct 28 11:52:20 2016 +0800 ---------------------------------------------------------------------- src/backend/gpopt/config/CConfigParamMapping.cpp | 7 +++++++ src/backend/utils/misc/guc.c | 11 +++++++++++ src/include/utils/guc.h | 1 + 3 files changed, 19 insertions(+) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/e7bba170/src/backend/gpopt/config/CConfigParamMapping.cpp ---------------------------------------------------------------------- diff --git a/src/backend/gpopt/config/CConfigParamMapping.cpp b/src/backend/gpopt/config/CConfigParamMapping.cpp index b7b0475..4a2073c 100644 --- a/src/backend/gpopt/config/CConfigParamMapping.cpp +++ b/src/backend/gpopt/config/CConfigParamMapping.cpp @@ -384,6 +384,13 @@ CConfigParamMapping::SConfigMappingElem CConfigParamMapping::m_elem[] = &optimizer_prefer_scalar_dqa_multistage_agg, false, // m_fNegate GPOS_WSZ_LIT("Prefer multistage aggregates for scalar distinct qualified aggregate in the optimizer.") + }, + + { + EopttraceEnableParallelAppend, + &optimizer_parallel_union, + false, // m_fNegate + GPOS_WSZ_LIT("Enable parallel execution for UNION/UNION ALL queries.") } }; http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/e7bba170/src/backend/utils/misc/guc.c ---------------------------------------------------------------------- diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index 2cdcb62..a936765 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -764,6 +764,7 @@ bool optimizer_multilevel_partitioning; bool optimizer_enable_derive_stats_all_groups; bool optimizer_explain_show_status; bool optimizer_prefer_scalar_dqa_multistage_agg; +bool optimizer_parallel_union; /* Security */ bool gp_reject_internal_tcp_conn = true; @@ -4387,6 +4388,16 @@ static struct config_bool ConfigureNamesBool[] = true, NULL, NULL }, + { + {"optimizer_parallel_union", PGC_USERSET, DEVELOPER_OPTIONS, + gettext_noop("Enable parallel execution for UNION/UNION ALL queries."), + NULL, + GUC_NO_SHOW_ALL | GUC_NOT_IN_SAMPLE + }, + &optimizer_parallel_union, + false, NULL, NULL + }, + /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL http://git-wip-us.apache.org/repos/asf/incubator-hawq/blob/e7bba170/src/include/utils/guc.h ---------------------------------------------------------------------- diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h index 41f7056..58b2b61 100644 --- a/src/include/utils/guc.h +++ b/src/include/utils/guc.h @@ -440,6 +440,7 @@ extern bool optimizer_multilevel_partitioning; extern bool optimizer_enable_derive_stats_all_groups; extern bool optimizer_explain_show_status; extern bool optimizer_prefer_scalar_dqa_multistage_agg; +extern bool optimizer_parallel_union; /** * Enable logging of DPE match in optimizer.
