From 9dfc8e0bde12cd4950c3e86dfe746a62d51d2afc Mon Sep 17 00:00:00 2001
From: Mark Holt <135143369+mh0lt@users.noreply.github.com>
Date: Thu, 28 Sep 2023 19:25:12 +0100
Subject: [PATCH] Only reduce the consensus db size based on flags values
 (#8321)

This is to fix an issue with resource usage if the db.size.limit is
increased from its default setting of 2TB. This is applied to the chain
DB, but should not be used on the consensus DB which has smaller data
requirements. Expanding both DBs results in excessive RAM being reserved
by the underlying OS.
---
 erigon-lib/kv/mdbx/kv_mdbx.go |  7 +++++--
 node/node.go                  | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/erigon-lib/kv/mdbx/kv_mdbx.go b/erigon-lib/kv/mdbx/kv_mdbx.go
index 847f772f2bc..3fc537c9ee9 100644
--- a/erigon-lib/kv/mdbx/kv_mdbx.go
+++ b/erigon-lib/kv/mdbx/kv_mdbx.go
@@ -70,6 +70,9 @@ type MdbxOpts struct {
 	inMem           bool
 }
 
+const DefaultMapSize = 2 * datasize.TB
+const DefaultGrowthStep = 2 * datasize.GB
+
 func NewMDBX(log log.Logger) MdbxOpts {
 	opts := MdbxOpts{
 		bucketsCfg: WithChaindataTables,
@@ -81,8 +84,8 @@ func NewMDBX(log log.Logger) MdbxOpts {
 		// but for reproducibility of benchmarks - please don't rely on Available RAM
 		dirtySpace: 2 * (memory.TotalMemory() / 42),
 
-		mapSize:         2 * datasize.TB,
-		growthStep:      2 * datasize.GB,
+		mapSize:         DefaultMapSize,
+		growthStep:      DefaultGrowthStep,
 		mergeThreshold:  3 * 8192,
 		shrinkThreshold: -1, // default
 		label:           kv.InMem,
diff --git a/node/node.go b/node/node.go
index 60a12240f93..06ba6018126 100644
--- a/node/node.go
+++ b/node/node.go
@@ -325,7 +325,7 @@ func OpenDatabase(config *nodecfg.Config, label kv.Label, name string, readonly
 		}
 
 		switch label {
-		case kv.ChainDB, kv.ConsensusDB:
+		case kv.ChainDB:
 			if config.MdbxPageSize.Bytes() > 0 {
 				opts = opts.PageSize(config.MdbxPageSize.Bytes())
 			}
@@ -335,6 +335,18 @@ func OpenDatabase(config *nodecfg.Config, label kv.Label, name string, readonly
 			if config.MdbxGrowthStep > 0 {
 				opts = opts.GrowthStep(config.MdbxGrowthStep)
 			}
+		case kv.ConsensusDB:
+			if config.MdbxPageSize.Bytes() > 0 {
+				opts = opts.PageSize(config.MdbxPageSize.Bytes())
+			}
+			// Don't adjust up the consensus DB - this will lead to resource exhaustion lor large map sizes
+			if config.MdbxDBSizeLimit > 0 && config.MdbxDBSizeLimit < mdbx.DefaultMapSize {
+				opts = opts.MapSize(config.MdbxDBSizeLimit)
+			}
+			// Don't adjust up the consensus DB - to align with db size limit above
+			if config.MdbxGrowthStep > 0 && config.MdbxGrowthStep < mdbx.DefaultGrowthStep {
+				opts = opts.GrowthStep(config.MdbxGrowthStep)
+			}
 		default:
 			opts = opts.GrowthStep(16 * datasize.MB)
 		}