From f5c8dfe7661a97cf4585af0c9aa56c26542d0038 Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Mon, 31 Jul 2023 19:25:26 +0100
Subject: [PATCH 1/2] Added maxTransactionsPerBlock setting (default 25) to
 reduce minting load on slower machines.

This is a short term limit, is well above current usage levels, and can be increased substantially in future once the block minter code has been improved.
---
 .../qortal/repository/TransactionRepository.java    |  2 +-
 .../transaction/HSQLDBTransactionRepository.java    | 13 ++++++++++---
 src/main/java/org/qortal/settings/Settings.java     |  7 +++++++
 .../java/org/qortal/transaction/Transaction.java    |  3 ++-
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/main/java/org/qortal/repository/TransactionRepository.java b/src/main/java/org/qortal/repository/TransactionRepository.java
index 6cc88290..41986cad 100644
--- a/src/main/java/org/qortal/repository/TransactionRepository.java
+++ b/src/main/java/org/qortal/repository/TransactionRepository.java
@@ -314,7 +314,7 @@ public interface TransactionRepository {
 	 * @return list of transactions, or empty if none.
 	 * @throws DataException
 	 */
-	public List<TransactionData> getUnconfirmedTransactions(EnumSet<TransactionType> excludedTxTypes) throws DataException;
+	public List<TransactionData> getUnconfirmedTransactions(EnumSet<TransactionType> excludedTxTypes, Integer limit) throws DataException;
 
 	/**
 	 * Remove transaction from unconfirmed transactions pile.
diff --git a/src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java b/src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java
index 740b3e65..60b4e803 100644
--- a/src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java
+++ b/src/main/java/org/qortal/repository/hsqldb/transaction/HSQLDBTransactionRepository.java
@@ -1429,8 +1429,10 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 	}
 
 	@Override
-	public List<TransactionData> getUnconfirmedTransactions(EnumSet<TransactionType> excludedTxTypes) throws DataException {
+	public List<TransactionData> getUnconfirmedTransactions(EnumSet<TransactionType> excludedTxTypes, Integer limit) throws DataException {
 		StringBuilder sql = new StringBuilder(1024);
+		List<Object> bindParams = new ArrayList<>();
+
 		sql.append("SELECT signature FROM UnconfirmedTransactions ");
 		sql.append("JOIN Transactions USING (signature) ");
 		sql.append("WHERE type NOT IN (");
@@ -1446,12 +1448,17 @@ public class HSQLDBTransactionRepository implements TransactionRepository {
 		}
 
 		sql.append(")");
-		sql.append("ORDER BY created_when, signature");
+		sql.append("ORDER BY created_when, signature ");
+
+		if (limit != null) {
+			sql.append("LIMIT ?");
+			bindParams.add(limit);
+		}
 
 		List<TransactionData> transactions = new ArrayList<>();
 
 		// Find transactions with no corresponding row in BlockTransactions
-		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString())) {
+		try (ResultSet resultSet = this.repository.checkedExecute(sql.toString(), bindParams.toArray())) {
 			if (resultSet == null)
 				return transactions;
 
diff --git a/src/main/java/org/qortal/settings/Settings.java b/src/main/java/org/qortal/settings/Settings.java
index c3d5a0c8..ac9b8857 100644
--- a/src/main/java/org/qortal/settings/Settings.java
+++ b/src/main/java/org/qortal/settings/Settings.java
@@ -146,6 +146,9 @@ public class Settings {
 	/* How many blocks to cache locally. Defaulted to 10, which covers a typical Synchronizer request + a few spare */
 	private int blockCacheSize = 10;
 
+	/** Maximum number of transactions for the block minter to include in a block */
+	private int maxTransactionsPerBlock = 25;
+
 	/** How long to keep old, full, AT state data (ms). */
 	private long atStatesMaxLifetime = 5 * 24 * 60 * 60 * 1000L; // milliseconds
 	/** How often to attempt AT state trimming (ms). */
@@ -693,6 +696,10 @@ public class Settings {
 		return this.blockCacheSize;
 	}
 
+	public int getMaxTransactionsPerBlock() {
+		return this.maxTransactionsPerBlock;
+	}
+
 	public boolean isTestNet() {
 		return this.isTestNet;
 	}
diff --git a/src/main/java/org/qortal/transaction/Transaction.java b/src/main/java/org/qortal/transaction/Transaction.java
index f0e9b3f6..10834a06 100644
--- a/src/main/java/org/qortal/transaction/Transaction.java
+++ b/src/main/java/org/qortal/transaction/Transaction.java
@@ -641,7 +641,8 @@ public abstract class Transaction {
 		BlockData latestBlockData = repository.getBlockRepository().getLastBlock();
 
 		EnumSet<TransactionType> excludedTxTypes = EnumSet.of(TransactionType.CHAT, TransactionType.PRESENCE);
-		List<TransactionData> unconfirmedTransactions = repository.getTransactionRepository().getUnconfirmedTransactions(excludedTxTypes);
+		int limit = Settings.getInstance().getMaxTransactionsPerBlock();
+		List<TransactionData> unconfirmedTransactions = repository.getTransactionRepository().getUnconfirmedTransactions(excludedTxTypes, limit);
 
 		unconfirmedTransactions.sort(getDataComparator());
 

From 94d3664cb092877f8348bea1d6342dbe5a95993d Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Mon, 31 Jul 2023 19:30:45 +0100
Subject: [PATCH 2/2] Bump version to 4.2.1

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index f236761e..1a046758 100644
--- a/pom.xml
+++ b/pom.xml
@@ -3,7 +3,7 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.qortal</groupId>
 	<artifactId>qortal</artifactId>
-	<version>4.2.0</version>
+	<version>4.2.1</version>
 	<packaging>jar</packaging>
 	<properties>
 		<skipTests>true</skipTests>