From 5d19626e35e50a5630e5f1a042f7ecee6acb7c70 Mon Sep 17 00:00:00 2001 From: Amit Khandekar Date: Wed, 9 Sep 2020 12:03:01 +0800 Subject: [PATCH 2/2] Add guc for ease of testing speedup. This is only for testing the performance gain. Otherwise, to compare the performance figures, it requires server restart, and the figures anyway shift back and forth by 5-15 percent after each restart, which creates lot of noise when comparing figures with and without fix. With this, we can easily see at least 4-10% difference in execution times by setting/unsetting the GUC enable_fix. --- src/backend/executor/tqueue.c | 12 ++++++++++++ src/backend/utils/misc/guc.c | 12 ++++++++++++ 2 files changed, 24 insertions(+) diff --git a/src/backend/executor/tqueue.c b/src/backend/executor/tqueue.c index c70ee0f39a..7dd60b5c7e 100644 --- a/src/backend/executor/tqueue.c +++ b/src/backend/executor/tqueue.c @@ -45,6 +45,7 @@ struct TupleQueueReader shm_mq_handle *queue; /* shm_mq to receive from */ }; +extern bool enable_fix; /* * Receive a tuple from a query, and send it to the designated shm_mq. * @@ -60,12 +61,23 @@ tqueueReceiveSlot(TupleTableSlot *slot, DestReceiver *self) bool should_free; /* Send the minimal tuple data. */ + if (enable_fix) + { minimal_tuple_data = ExecFetchSlotMinimalTupleData(slot, &len, &should_free); result = shm_mq_send(tqueue->queue, len, minimal_tuple_data, false); if (should_free) pfree(minimal_tuple_data); + } + else + { + MinimalTuple tuple; + tuple = ExecFetchSlotMinimalTuple(slot, &should_free); + result = shm_mq_send(tqueue->queue, tuple->t_len, tuple, false); + if (should_free) + pfree(tuple); + } /* Check for failure. */ if (result == SHM_MQ_DETACHED) return false; diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index de87ad6ef7..8b3f1339cb 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -138,6 +138,8 @@ extern bool trace_syncscan; extern bool optimize_bounded_sort; #endif +bool enable_fix = true; + static int GUC_check_errcode_value; /* global variables for check hook support */ @@ -2036,6 +2038,16 @@ static struct config_bool ConfigureNamesBool[] = NULL, NULL, NULL }, + { + {"enable_fix", PGC_USERSET, RESOURCES_ASYNCHRONOUS, + gettext_noop("dummy"), + gettext_noop("dummy"), + GUC_EXPLAIN + }, + &enable_fix, + true, + NULL, NULL, NULL + }, /* End-of-list marker */ { {NULL, 0, 0, NULL, NULL}, NULL, false, NULL, NULL, NULL -- 2.17.1