v46-0003-Pass-down-information-on-table-modification-to-s.patch
text/x-patch
Filename: v46-0003-Pass-down-information-on-table-modification-to-s.patch
Type: text/x-patch
Part: 2
Patch
Same data as JSON:
GET /api/v1/attachments/:id/patch
the parsed metadata as JSON — format, series position, per-file stats; never the diff bytes.
API reference →
Format: format-patch
Series: patch v46-0003
Subject: Pass down information on table modification to scan node
| File | + | − |
|---|---|---|
| src/backend/executor/execUtils.c | 8 | 0 |
| src/backend/executor/nodeBitmapHeapscan.c | 2 | 1 |
| src/backend/executor/nodeIndexonlyscan.c | 6 | 3 |
| src/backend/executor/nodeIndexscan.c | 8 | 4 |
| src/backend/executor/nodeSamplescan.c | 2 | 1 |
| src/backend/executor/nodeSeqscan.c | 7 | 3 |
| src/backend/executor/nodeTidrangescan.c | 8 | 3 |
| src/include/access/tableam.h | 3 | 0 |
| src/include/executor/executor.h | 2 | 0 |
From 105c2c2c0057ee9945cf6ec1c32061f617f627a2 Mon Sep 17 00:00:00 2001
From: Melanie Plageman <melanieplageman@gmail.com>
Date: Mon, 2 Mar 2026 16:31:33 -0500
Subject: [PATCH v46 3/5] Pass down information on table modification to scan
node
Pass down information to sequential scan, index [only] scan, bitmap
table scan, sample scan, and TID range scan nodes on whether or not the
query modifies the relation being scanned. A later commit will use this
information to update the VM during on-access pruning only if the
relation is not modified by the query.
Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/4379FDA3-9446-4E2C-9C15-32EFE8D4F31B%40yandex-team.ru
---
src/backend/executor/execUtils.c | 8 ++++++++
src/backend/executor/nodeBitmapHeapscan.c | 3 ++-
src/backend/executor/nodeIndexonlyscan.c | 9 ++++++---
src/backend/executor/nodeIndexscan.c | 12 ++++++++----
src/backend/executor/nodeSamplescan.c | 3 ++-
src/backend/executor/nodeSeqscan.c | 10 +++++++---
src/backend/executor/nodeTidrangescan.c | 11 ++++++++---
src/include/access/tableam.h | 3 +++
src/include/executor/executor.h | 2 ++
9 files changed, 46 insertions(+), 15 deletions(-)
diff --git a/src/backend/executor/execUtils.c b/src/backend/executor/execUtils.c
index 9886ab06b69..d2ffe28e010 100644
--- a/src/backend/executor/execUtils.c
+++ b/src/backend/executor/execUtils.c
@@ -736,6 +736,14 @@ ExecRelationIsTargetRelation(EState *estate, Index scanrelid)
return list_member_int(estate->es_plannedstmt->resultRelations, scanrelid);
}
+/* Return true if the scan node's relation is not modified by the query */
+bool
+ScanRelIsReadOnly(ScanState *ss)
+{
+ return !bms_is_member(((Scan *) ss->ps.plan)->scanrelid,
+ ss->ps.state->es_plannedstmt->modifiedRelids);
+}
+
/* ----------------------------------------------------------------
* ExecOpenScanRelation
*
diff --git a/src/backend/executor/nodeBitmapHeapscan.c b/src/backend/executor/nodeBitmapHeapscan.c
index e58bb02db43..7096e6f8645 100644
--- a/src/backend/executor/nodeBitmapHeapscan.c
+++ b/src/backend/executor/nodeBitmapHeapscan.c
@@ -149,7 +149,8 @@ BitmapTableScanSetup(BitmapHeapScanState *node)
node->ss.ps.state->es_snapshot,
0,
NULL,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
node->ss.ss_currentScanDesc->st.rs_tbmiterator = tbmiterator;
diff --git a/src/backend/executor/nodeIndexonlyscan.c b/src/backend/executor/nodeIndexonlyscan.c
index f8a6671793f..3971e54d7da 100644
--- a/src/backend/executor/nodeIndexonlyscan.c
+++ b/src/backend/executor/nodeIndexonlyscan.c
@@ -96,7 +96,8 @@ IndexOnlyNext(IndexOnlyScanState *node)
node->ioss_Instrument,
node->ioss_NumScanKeys,
node->ioss_NumOrderByKeys,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->ioss_ScanDesc = scandesc;
@@ -796,7 +797,8 @@ ExecIndexOnlyScanInitializeDSM(IndexOnlyScanState *node,
node->ioss_NumScanKeys,
node->ioss_NumOrderByKeys,
piscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->ioss_ScanDesc->xs_want_itup = true;
node->ioss_VMBuffer = InvalidBuffer;
@@ -863,7 +865,8 @@ ExecIndexOnlyScanInitializeWorker(IndexOnlyScanState *node,
node->ioss_NumScanKeys,
node->ioss_NumOrderByKeys,
piscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->ioss_ScanDesc->xs_want_itup = true;
/*
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 3df091ac000..09df10dd78a 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -114,7 +114,8 @@ IndexNext(IndexScanState *node)
node->iss_Instrument,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->iss_ScanDesc = scandesc;
@@ -211,7 +212,8 @@ IndexNextWithReorder(IndexScanState *node)
node->iss_Instrument,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->iss_ScanDesc = scandesc;
@@ -1733,7 +1735,8 @@ ExecIndexScanInitializeDSM(IndexScanState *node,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
piscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
/*
* If no run-time keys to calculate or they are ready, go ahead and pass
@@ -1798,7 +1801,8 @@ ExecIndexScanInitializeWorker(IndexScanState *node,
node->iss_NumScanKeys,
node->iss_NumOrderByKeys,
piscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
/*
* If no run-time keys to calculate or they are ready, go ahead and pass
diff --git a/src/backend/executor/nodeSamplescan.c b/src/backend/executor/nodeSamplescan.c
index f0e14e53fab..98fab36fbdc 100644
--- a/src/backend/executor/nodeSamplescan.c
+++ b/src/backend/executor/nodeSamplescan.c
@@ -299,7 +299,8 @@ tablesample_init(SampleScanState *scanstate)
scanstate->use_bulkread,
allow_sync,
scanstate->use_pagemode,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&scanstate->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
else
{
diff --git a/src/backend/executor/nodeSeqscan.c b/src/backend/executor/nodeSeqscan.c
index eaa8cfb6a1a..2f4c18051cd 100644
--- a/src/backend/executor/nodeSeqscan.c
+++ b/src/backend/executor/nodeSeqscan.c
@@ -72,7 +72,8 @@ SeqNext(SeqScanState *node)
scandesc = table_beginscan(node->ss.ss_currentRelation,
estate->es_snapshot,
0, NULL,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->ss.ss_currentScanDesc = scandesc;
}
@@ -375,9 +376,11 @@ ExecSeqScanInitializeDSM(SeqScanState *node,
pscan,
estate->es_snapshot);
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pscan);
+
node->ss.ss_currentScanDesc =
table_beginscan_parallel(node->ss.ss_currentRelation, pscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
/* ----------------------------------------------------------------
@@ -411,5 +414,6 @@ ExecSeqScanInitializeWorker(SeqScanState *node,
pscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
node->ss.ss_currentScanDesc =
table_beginscan_parallel(node->ss.ss_currentRelation, pscan,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
diff --git a/src/backend/executor/nodeTidrangescan.c b/src/backend/executor/nodeTidrangescan.c
index 6f63e9f80d0..f83a72e3635 100644
--- a/src/backend/executor/nodeTidrangescan.c
+++ b/src/backend/executor/nodeTidrangescan.c
@@ -246,7 +246,8 @@ TidRangeNext(TidRangeScanState *node)
estate->es_snapshot,
&node->trss_mintid,
&node->trss_maxtid,
- 0 /* flags */ );
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
node->ss.ss_currentScanDesc = scandesc;
}
else
@@ -461,7 +462,9 @@ ExecTidRangeScanInitializeDSM(TidRangeScanState *node, ParallelContext *pcxt)
shm_toc_insert(pcxt->toc, node->ss.ps.plan->plan_node_id, pscan);
node->ss.ss_currentScanDesc =
table_beginscan_parallel_tidrange(node->ss.ss_currentRelation,
- pscan, 0 /* flags */ );
+ pscan,
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
/* ----------------------------------------------------------------
@@ -495,5 +498,7 @@ ExecTidRangeScanInitializeWorker(TidRangeScanState *node,
pscan = shm_toc_lookup(pwcxt->toc, node->ss.ps.plan->plan_node_id, false);
node->ss.ss_currentScanDesc =
table_beginscan_parallel_tidrange(node->ss.ss_currentRelation,
- pscan, 0 /* flags */ );
+ pscan,
+ ScanRelIsReadOnly(&node->ss) ?
+ SO_HINT_REL_READ_ONLY : 0);
}
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index ce5176bdf69..014c686a5de 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -63,6 +63,9 @@ typedef enum ScanOptions
/* unregister snapshot at scan end? */
SO_TEMP_SNAPSHOT = 1 << 9,
+
+ /* set if the query doesn't modify the relation */
+ SO_HINT_REL_READ_ONLY = 1 << 10,
} ScanOptions;
/*
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 07f4b1f7490..7979a17e4ec 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -690,6 +690,8 @@ extern void ExecCreateScanSlotFromOuterPlan(EState *estate,
extern bool ExecRelationIsTargetRelation(EState *estate, Index scanrelid);
+extern bool ScanRelIsReadOnly(ScanState *ss);
+
extern Relation ExecOpenScanRelation(EState *estate, Index scanrelid, int eflags);
extern void ExecInitRangeTable(EState *estate, List *rangeTable, List *permInfos,
--
2.43.0