MAJOR: Don't delete transactions when orphaning - make them unconfirmed again

Lots of edits to Transaction subclasses to change/remove 'delete'.

Corresponding extra changes to help reset some transaction fields to pre-process
state during orphaning.

Changed Block, GenesisBlock & Synchronizer to save transactions where appropriate.

Added enhanced GET_SIGNATURES_V2 network message to reduce the number of
block signatures sent over network.

Peers are now version 2 if they send a new-style build version string,
instead of using first digit from build version.

src/main/java/org/qora/asset/Asset.java

@@ -156,6 +156,9 @@ public class Asset {
 
 		// Save reverted asset
 		this.repository.getAssetRepository().save(this.assetData);
+
+		// Remove reference to previous asset-changing transaction
+		updateAssetTransactionData.setOrphanReference(null);
 	}
 
 }

src/main/java/org/qora/block/Block.java

@@ -34,6 +34,7 @@ import org.qora.repository.Repository;
 import org.qora.transaction.AtTransaction;
 import org.qora.transaction.GenesisTransaction;
 import org.qora.transaction.Transaction;
+import org.qora.transaction.Transaction.TransactionType;
 import org.qora.transform.TransformationException;
 import org.qora.transform.block.BlockTransformer;
 import org.qora.transform.transaction.TransactionTransformer;
@@ -1045,10 +1046,15 @@ public class Block {
 		processBlockRewards();
 
 		// Process transactions (we'll link them to this block after saving the block itself)
-		// AT-generated transactions are already added to our transactions so no special handling is needed here.
+		// AT-generated transactions are already prepended to our transactions at this point.
 		List<Transaction> transactions = this.getTransactions();
-		for (Transaction transaction : transactions)
+		for (Transaction transaction : transactions) {
+			// AT_TRANSACTIONs are created locally and need saving into repository before processing
+			if (transaction.getTransactionData().getType() == TransactionType.AT)
+				this.repository.getTransactionRepository().save(transaction.getTransactionData());
+
 			transaction.process();
+		}
 
 		// Give transaction fees to generator/proxy
 		rewardTransactionFees();
@@ -1158,9 +1164,11 @@ public class Block {
 					transaction.getTransactionData().getSignature());
 			this.repository.getBlockRepository().delete(blockTransactionData);
 
-			// Add to unconfirmed pile
-			// XXX WE CAN'T ADD TO UNCONFIRMED AS TRANSACTION HAS BEEN DELETED BY transaction.orphan() ABOVE
-			// this.repository.getTransactionRepository().unconfirmTransaction(transaction.getTransactionData());
+			// Add to unconfirmed pile, or delete if AT_TRANSACTION
+			if (transaction.getTransactionData().getType() == TransactionType.AT)
+				this.repository.getTransactionRepository().delete(transaction.getTransactionData());
+			else
+				this.repository.getTransactionRepository().unconfirmTransaction(transaction.getTransactionData());
 
 			this.repository.getTransactionRepository().deleteParticipants(transaction.getTransactionData());
 		}

src/main/java/org/qora/block/GenesisBlock.java

@@ -318,6 +318,10 @@ public class GenesisBlock extends Block {
 			this.repository.rollbackToSavepoint();
 		}
 
+		// Save transactions into repository ready for processing
+		for (Transaction transaction : this.getTransactions())
+			this.repository.getTransactionRepository().save(transaction.getTransactionData());
+
 		super.process();
 	}
 

src/main/java/org/qora/controller/Controller.java

@@ -34,6 +34,7 @@ import org.qora.network.message.GetBlockMessage;
 import org.qora.network.message.GetBlockSummariesMessage;
 import org.qora.network.message.GetPeersMessage;
 import org.qora.network.message.GetSignaturesMessage;
+import org.qora.network.message.GetSignaturesV2Message;
 import org.qora.network.message.HeightMessage;
 import org.qora.network.message.Message;
 import org.qora.network.message.SignaturesMessage;
@@ -165,6 +166,7 @@ public class Controller extends Thread {
 		LOGGER.info("Validating blockchain");
 		try {
 			BlockChain.validate();
+			LOGGER.info(String.format("Our chain height at start-up: %d", getInstance().getChainHeight()));
 		} catch (DataException e) {
 			LOGGER.error("Couldn't validate blockchain", e);
 			System.exit(2);
@@ -415,6 +417,32 @@ public class Controller extends Thread {
 				}
 				break;
 
+			case GET_SIGNATURES_V2:
+				try (final Repository repository = RepositoryManager.getRepository()) {
+					GetSignaturesV2Message getSignaturesMessage = (GetSignaturesV2Message) message;
+					byte[] parentSignature = getSignaturesMessage.getParentSignature();
+
+					List<byte[]> signatures = new ArrayList<>();
+
+					do {
+						BlockData blockData = repository.getBlockRepository().fromReference(parentSignature);
+
+						if (blockData == null)
+							break;
+
+						parentSignature = blockData.getSignature();
+						signatures.add(parentSignature);
+					} while (signatures.size() < getSignaturesMessage.getNumberRequested());
+
+					Message signaturesMessage = new SignaturesMessage(signatures);
+					signaturesMessage.setId(message.getId());
+					if (!peer.sendMessage(signaturesMessage))
+						peer.disconnect();
+				} catch (DataException e) {
+					LOGGER.error(String.format("Repository issue while responding to %s from peer %s", message.getType().name(), peer), e);
+				}
+				break;
+
 			case GET_BLOCK:
 				try (final Repository repository = RepositoryManager.getRepository()) {
 					GetBlockMessage getBlockMessage = (GetBlockMessage) message;

src/main/java/org/qora/controller/Synchronizer.java

@@ -18,12 +18,14 @@ import org.qora.network.message.BlockSummariesMessage;
 import org.qora.network.message.GetBlockMessage;
 import org.qora.network.message.GetBlockSummariesMessage;
 import org.qora.network.message.GetSignaturesMessage;
+import org.qora.network.message.GetSignaturesV2Message;
 import org.qora.network.message.Message;
 import org.qora.network.message.Message.MessageType;
 import org.qora.network.message.SignaturesMessage;
 import org.qora.repository.DataException;
 import org.qora.repository.Repository;
 import org.qora.repository.RepositoryManager;
+import org.qora.transaction.Transaction;
 
 public class Synchronizer {
 
@@ -168,10 +170,11 @@ public class Synchronizer {
 
 						// Fetch, and apply, blocks from peer
 						byte[] signature = commonBlockData.getSignature();
-						while (ourHeight < peerHeight && ourHeight < commonBlockHeight + SYNC_BATCH_SIZE) {
+						int maxBatchHeight = commonBlockHeight + SYNC_BATCH_SIZE;
+						while (ourHeight < peerHeight && ourHeight < maxBatchHeight) {
 							// Do we need more signatures?
 							if (signatures.isEmpty()) {
-								signatures = this.getBlockSignatures(peer, signature, MAXIMUM_BLOCK_STEP);
+								signatures = this.getBlockSignatures(peer, signature, maxBatchHeight - ourHeight);
 								if (signatures == null || signatures.isEmpty()) {
 									LOGGER.info(String.format("Peer %s failed to respond with more block signatures after height %d", peer, ourHeight));
 									return SynchronizationResult.NO_REPLY;
@@ -200,6 +203,10 @@ public class Synchronizer {
 								return SynchronizationResult.INVALID_DATA;
 							}
 
+							// Save transactions attached to this block
+							for (Transaction transaction : newBlock.getTransactions())
+								repository.getTransactionRepository().save(transaction.getTransactionData());
+
 							newBlock.process();
 
 							// If we've grown our blockchain then at least save progress so far
@@ -316,8 +323,9 @@ public class Synchronizer {
 	}
 
 	private List<byte[]> getBlockSignatures(Peer peer, byte[] parentSignature, int numberRequested) {
-		// TODO numberRequested is v2+ feature
-		Message getSignaturesMessage = new GetSignaturesMessage(parentSignature);
+		// numberRequested is v2+ feature
+		Message getSignaturesMessage = peer.getVersion() >= 2 ? new GetSignaturesV2Message(parentSignature, numberRequested) : new GetSignaturesMessage(parentSignature);
+		// Message getSignaturesMessage = new GetSignaturesMessage(parentSignature);
 
 		Message message = peer.getResponse(getSignaturesMessage);
 		if (message == null || message.getType() != MessageType.SIGNATURES)

src/main/java/org/qora/data/transaction/SetGroupTransactionData.java

@@ -65,7 +65,7 @@ public class SetGroupTransactionData extends TransactionData {
 		return this.previousDefaultGroupId;
 	}
 
-	public void setPreviousDefaultGroupId(int previousDefaultGroupId) {
+	public void setPreviousDefaultGroupId(Integer previousDefaultGroupId) {
 		this.previousDefaultGroupId = previousDefaultGroupId;
 	}
 

src/main/java/org/qora/group/Group.java

@@ -361,6 +361,9 @@ public class Group {
 			if (Arrays.equals(groupMemberData.getReference(), updateGroupTransactionData.getSignature()))
 				this.deleteMember(newOwner);
 		}
+
+		// Remove cached reference to previous group change from transaction data
+		updateGroupTransactionData.setGroupReference(null);
 	}
 
 	/** Reverts groupData using previous values stored in referenced transaction. */
@@ -485,27 +488,27 @@ public class Group {
 		if (joinReference != null) {
 			// Rebuild join-request
 			this.rebuildJoinRequest(member, joinReference);
+		} else {
+			// Rebuild member entry using stored transaction reference
+			this.rebuildMember(member, groupKickTransactionData.getMemberReference());
 
-			return;
+			// Revert member's defaultGroupId if necessary
+			Integer previousDefaultGroupId = groupKickTransactionData.getPreviousGroupId();
+			if (previousDefaultGroupId != null) {
+				Account memberAccount = new Account(this.repository, member);
+				memberAccount.setDefaultGroupId(previousDefaultGroupId);
+			}
+
+			if (groupKickTransactionData.getAdminReference() != null)
+				// Rebuild admin entry using stored transaction reference
+				this.rebuildAdmin(member, groupKickTransactionData.getAdminReference());
 		}
 
-		// Rebuild member entry using stored transaction reference
-		this.rebuildMember(member, groupKickTransactionData.getMemberReference());
-
-		// Revert member's defaultGroupId if necessary
-		Integer previousDefaultGroupId = groupKickTransactionData.getPreviousGroupId();
-		if (previousDefaultGroupId != null) {
-			Account memberAccount = new Account(this.repository, member);
-			memberAccount.setDefaultGroupId(previousDefaultGroupId);
-		}
-
-		if (groupKickTransactionData.getAdminReference() != null)
-			// Rebuild admin entry using stored transaction reference
-			this.rebuildAdmin(member, groupKickTransactionData.getAdminReference());
-
 		// Clean cached references to transactions used to rebuild member/admin info
 		groupKickTransactionData.setMemberReference(null);
 		groupKickTransactionData.setAdminReference(null);
+		groupKickTransactionData.setJoinReference(null);
+		groupKickTransactionData.setPreviousGroupId(null);
 	}
 
 	public void ban(GroupBanTransactionData groupBanTransactionData) throws DataException {
@@ -622,6 +625,12 @@ public class Group {
 				}
 			}
 		}
+
+		// Remove any group-related references from transaction data
+		groupBanTransactionData.setMemberReference(null);
+		groupBanTransactionData.setAdminReference(null);
+		groupBanTransactionData.setJoinInviteReference(null);
+		groupBanTransactionData.setPreviousGroupId(null);
 	}
 
 	public void cancelBan(CancelGroupBanTransactionData groupUnbanTransactionData) throws DataException {
@@ -697,6 +706,10 @@ public class Group {
 
 		// Delete invite
 		this.deleteInvite(invitee);
+
+		// Clear cached references
+		groupInviteTransactionData.setJoinReference(null);
+		groupInviteTransactionData.setPreviousGroupId(null);
 	}
 
 	public void cancelInvite(CancelGroupInviteTransactionData cancelGroupInviteTransactionData) throws DataException {
@@ -769,27 +782,29 @@ public class Group {
 		if (inviteReference == null && !groupData.getIsOpen()) {
 			// Delete join request
 			this.deleteJoinRequest(joiner.getAddress());
+		} else {
+			// Any invite to rebuild?
+			if (inviteReference != null) {
+				// Rebuild invite using cache reference to invite transaction
+				TransactionData transactionData = this.repository.getTransactionRepository().fromSignature(inviteReference);
+				this.addInvite((GroupInviteTransactionData) transactionData);
 
-			return;
+				// Clear cached reference to invite transaction
+				joinGroupTransactionData.setInviteReference(null);
+			}
+
+			// Delete member
+			this.deleteMember(joiner.getAddress());
+
+			// Revert joiner's defaultGroupId if necessary
+			Integer previousDefaultGroupId = joinGroupTransactionData.getPreviousGroupId();
+			if (previousDefaultGroupId != null)
+				joiner.setDefaultGroupId(previousDefaultGroupId);
 		}
 
-		// Any invite to rebuild?
-		if (inviteReference != null) {
-			// Rebuild invite using cache reference to invite transaction
-			TransactionData transactionData = this.repository.getTransactionRepository().fromSignature(inviteReference);
-			this.addInvite((GroupInviteTransactionData) transactionData);
-
-			// Clear cached reference to invite transaction
-			joinGroupTransactionData.setInviteReference(null);
-		}
-
-		// Delete member
-		this.deleteMember(joiner.getAddress());
-
-		// Revert joiner's defaultGroupId if necessary
-		Integer previousDefaultGroupId = joinGroupTransactionData.getPreviousGroupId();
-		if (previousDefaultGroupId != null)
-			joiner.setDefaultGroupId(previousDefaultGroupId);
+		// Clear cached references
+		joinGroupTransactionData.setInviteReference(null);
+		joinGroupTransactionData.setPreviousGroupId(null);
 	}
 
 	public void leave(LeaveGroupTransactionData leaveGroupTransactionData) throws DataException {
@@ -842,6 +857,11 @@ public class Group {
 		Integer previousDefaultGroupId = leaveGroupTransactionData.getPreviousGroupId();
 		if (previousDefaultGroupId != null)
 			leaver.setDefaultGroupId(previousDefaultGroupId);
+
+		// Clear cached references
+		leaveGroupTransactionData.setAdminReference(null);
+		leaveGroupTransactionData.setMemberReference(null);
+		leaveGroupTransactionData.setPreviousGroupId(null);
 	}
 
 }

src/main/java/org/qora/naming/Name.java

@@ -113,6 +113,9 @@ public class Name {
 
 		// Save reverted name data
 		this.repository.getNameRepository().save(this.nameData);
+
+		// Remove reference to previous name-changing transaction
+		updateNameTransactionData.setNameReference(null);
 	}
 
 	public void sell(SellNameTransactionData sellNameTransactionData) throws DataException {
@@ -133,7 +136,7 @@ public class Name {
 		this.repository.getNameRepository().save(this.nameData);
 	}
 
-	public void sell(CancelSellNameTransactionData cancelSellNameTransactionData) throws DataException {
+	public void cancelSell(CancelSellNameTransactionData cancelSellNameTransactionData) throws DataException {
 		// Mark not for-sale but leave price in case we want to orphan
 		this.nameData.setIsForSale(false);
 
@@ -141,7 +144,7 @@ public class Name {
 		this.repository.getNameRepository().save(this.nameData);
 	}
 
-	public void unsell(CancelSellNameTransactionData cancelSellNameTransactionData) throws DataException {
+	public void uncancelSell(CancelSellNameTransactionData cancelSellNameTransactionData) throws DataException {
 		// Mark as for-sale using existing price
 		this.nameData.setIsForSale(true);
 
@@ -180,6 +183,9 @@ public class Name {
 		// Previous name reference is taken from this transaction's cached copy
 		this.nameData.setReference(buyNameTransactionData.getNameReference());
 
+		// Remove reference in transaction data
+		buyNameTransactionData.setNameReference(null);
+
 		// Revert buyer's balance
 		Account buyer = new PublicKeyAccount(this.repository, buyNameTransactionData.getBuyerPublicKey());
 		buyer.setConfirmedBalance(Asset.QORA, buyer.getConfirmedBalance(Asset.QORA).add(buyNameTransactionData.getAmount()));

src/main/java/org/qora/network/Peer.java

@@ -99,14 +99,9 @@ public class Peer implements Runnable {
 		this.versionMessage = versionMessage;
 
 		if (this.versionMessage.getVersionString().startsWith(Controller.VERSION_PREFIX)) {
-			int index = Controller.VERSION_PREFIX.length();
-			try {
-				this.version = Integer.parseInt(this.versionMessage.getVersionString().substring(index, index + 1));
-			} catch (NumberFormatException e) {
-				this.version = 1;
-			}
+			this.version = 2; // enhanced protocol
 		} else {
-			this.version = 1;
+			this.version = 1; // legacy protocol
 		}
 	}
 

src/main/java/org/qora/network/message/GetSignaturesV2Message.java

@@ -0,0 +1,67 @@
+package org.qora.network.message;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.UnsupportedEncodingException;
+import java.nio.ByteBuffer;
+
+import org.qora.transform.Transformer;
+import org.qora.transform.block.BlockTransformer;
+
+import com.google.common.primitives.Ints;
+
+public class GetSignaturesV2Message extends Message {
+
+	private static final int BLOCK_SIGNATURE_LENGTH = BlockTransformer.BLOCK_SIGNATURE_LENGTH;
+	private static final int NUMBER_REQUESTED_LENGTH = Transformer.INT_LENGTH;
+
+	private byte[] parentSignature;
+	private int numberRequested;
+
+	public GetSignaturesV2Message(byte[] parentSignature, int numberRequested) {
+		this(-1, parentSignature, numberRequested);
+	}
+
+	private GetSignaturesV2Message(int id, byte[] parentSignature, int numberRequested) {
+		super(id, MessageType.GET_SIGNATURES_V2);
+
+		this.parentSignature = parentSignature;
+		this.numberRequested = numberRequested;
+	}
+
+	public byte[] getParentSignature() {
+		return this.parentSignature;
+	}
+
+	public int getNumberRequested() {
+		return this.numberRequested;
+	}
+
+	public static Message fromByteBuffer(int id, ByteBuffer bytes) throws UnsupportedEncodingException {
+		if (bytes.remaining() != BLOCK_SIGNATURE_LENGTH + NUMBER_REQUESTED_LENGTH)
+			return null;
+
+		byte[] parentSignature = new byte[BLOCK_SIGNATURE_LENGTH];
+		bytes.get(parentSignature);
+
+		int numberRequested = bytes.getInt();
+
+		return new GetSignaturesV2Message(id, parentSignature, numberRequested);
+	}
+
+	@Override
+	protected byte[] toData() {
+		try {
+			ByteArrayOutputStream bytes = new ByteArrayOutputStream();
+
+			bytes.write(this.parentSignature);
+
+			bytes.write(Ints.toByteArray(this.numberRequested));
+
+			return bytes.toByteArray();
+		} catch (IOException e) {
+			return null;
+		}
+	}
+
+}

src/main/java/org/qora/network/message/Message.java

@@ -42,7 +42,8 @@ public abstract class Message {
 		PROOF(12),
 		PEERS_V2(13),
 		GET_BLOCK_SUMMARIES(14),
-		BLOCK_SUMMARIES(15);
+		BLOCK_SUMMARIES(15),
+		GET_SIGNATURES_V2(16);
 
 		public final int value;
 		public final Method fromByteBuffer;

src/main/java/org/qora/transaction/AccountFlagsTransaction.java

@@ -129,8 +129,9 @@ public class AccountFlagsTransaction extends Transaction {
 		else
 			target.setFlags(previousFlags);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(accountFlagsTransactionData);
+		// Remove previous flags from transaction itself
+		accountFlagsTransactionData.setPreviousFlags(null);
+		this.repository.getTransactionRepository().save(accountFlagsTransactionData);
 
 		Account creator = getCreator();
 

src/main/java/org/qora/transaction/AddGroupAdminTransaction.java

@@ -121,8 +121,7 @@ public class AddGroupAdminTransaction extends Transaction {
 		Group group = new Group(this.repository, addGroupAdminTransactionData.getGroupId());
 		group.promoteToAdmin(addGroupAdminTransactionData);
 
-		// Save this transaction
-		this.repository.getTransactionRepository().save(addGroupAdminTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update owner's balance
 		Account owner = getOwner();
@@ -138,8 +137,7 @@ public class AddGroupAdminTransaction extends Transaction {
 		Group group = new Group(this.repository, addGroupAdminTransactionData.getGroupId());
 		group.unpromoteToAdmin(addGroupAdminTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(addGroupAdminTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/ArbitraryTransaction.java

@@ -115,14 +115,7 @@ public class ArbitraryTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		/*
-		 * Save the transaction.
-		 * 
-		 * We might have either raw data or only a hash of data, depending on content filtering.
-		 * If we have raw data then the repository save will store the raw data somewhere and save the data's hash in the repository.
-		 * This also modifies the passed transactionData.
-		 */
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Wrap and delegate payment processing to Payment class. Always update recipients' last references regardless of asset.
 		new Payment(this.repository).process(arbitraryTransactionData.getSenderPublicKey(), arbitraryTransactionData.getPayments(),
@@ -131,16 +124,11 @@ public class ArbitraryTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		/*
-		 * Delete the transaction.
-		 * 
-		 * The repository will also remove the stored raw data, if present.
-		 */
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		// Wrap and delegate payment processing to Payment class. Always revert recipients' last references regardless of asset.
 		new Payment(this.repository).orphan(arbitraryTransactionData.getSenderPublicKey(), arbitraryTransactionData.getPayments(),
 				arbitraryTransactionData.getFee(), arbitraryTransactionData.getSignature(), arbitraryTransactionData.getReference(), true);
+
+		// We would save transaction in orphaned form at this point, but it hasn't been modified
 	}
 
 	// Data access

src/main/java/org/qora/transaction/AtTransaction.java

@@ -159,8 +159,7 @@ public class AtTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		if (this.atTransactionData.getAmount() != null) {
 			Account sender = getATAccount();
@@ -185,9 +184,6 @@ public class AtTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		if (this.atTransactionData.getAmount() != null) {
 			Account sender = getATAccount();
 			Account recipient = getRecipient();
@@ -208,6 +204,10 @@ public class AtTransaction extends Transaction {
 			if (assetId == Asset.QORA && Arrays.equals(recipient.getLastReference(), this.atTransactionData.getSignature()))
 				recipient.setLastReference(null);
 		}
+
+		// We would save updated transaction at this point, but it hasn't been modified
+
+		// As AT_TRANSACTIONs are really part of a block, the caller (Block) will probably delete this transaction after orphaning
 	}
 
 }

src/main/java/org/qora/transaction/BuyNameTransaction.java

@@ -127,7 +127,7 @@ public class BuyNameTransaction extends Transaction {
 		Name name = new Name(this.repository, buyNameTransactionData.getName());
 		name.buy(buyNameTransactionData);
 
-		// Save this transaction, now with updated "name reference" to previous transaction that updated name
+		// Save transaction with updated "name reference" pointing to previous transaction that updated name
 		this.repository.getTransactionRepository().save(buyNameTransactionData);
 
 		// Update buyer's balance
@@ -144,8 +144,8 @@ public class BuyNameTransaction extends Transaction {
 		Name name = new Name(this.repository, buyNameTransactionData.getName());
 		name.unbuy(buyNameTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(buyNameTransactionData);
+		// Save this transaction, with removed "name reference"
+		this.repository.getTransactionRepository().save(buyNameTransactionData);
 
 		// Update buyer's balance
 		Account buyer = getBuyer();

src/main/java/org/qora/transaction/CancelAssetOrderTransaction.java

@@ -101,8 +101,7 @@ public class CancelAssetOrderTransaction extends Transaction {
 	public void process() throws DataException {
 		Account creator = getCreator();
 
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update creator's balance regarding fee
 		creator.setConfirmedBalance(Asset.QORA, creator.getConfirmedBalance(Asset.QORA).subtract(cancelOrderTransactionData.getFee()));
@@ -120,8 +119,7 @@ public class CancelAssetOrderTransaction extends Transaction {
 	public void orphan() throws DataException {
 		Account creator = getCreator();
 
-		// Save this transaction itself
-		this.repository.getTransactionRepository().delete(this.transactionData);
+		// We would save transaction in orphaned form at this point, but it hasn't been modified
 
 		// Update creator's balance regarding fee
 		creator.setConfirmedBalance(Asset.QORA, creator.getConfirmedBalance(Asset.QORA).add(cancelOrderTransactionData.getFee()));

src/main/java/org/qora/transaction/CancelGroupBanTransaction.java

@@ -134,8 +134,8 @@ public class CancelGroupBanTransaction extends Transaction {
 		Group group = new Group(this.repository, groupUnbanTransactionData.getGroupId());
 		group.uncancelBan(groupUnbanTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(groupUnbanTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(groupUnbanTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/CancelGroupInviteTransaction.java

@@ -134,8 +134,8 @@ public class CancelGroupInviteTransaction extends Transaction {
 		Group group = new Group(this.repository, cancelGroupInviteTransactionData.getGroupId());
 		group.uncancelInvite(cancelGroupInviteTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(cancelGroupInviteTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(cancelGroupInviteTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/CancelSellNameTransaction.java

@@ -112,9 +112,9 @@ public class CancelSellNameTransaction extends Transaction {
 	public void process() throws DataException {
 		// Update Name
 		Name name = new Name(this.repository, cancelSellNameTransactionData.getName());
-		name.sell(cancelSellNameTransactionData);
+		name.cancelSell(cancelSellNameTransactionData);
 
-		// Save this transaction, now with updated "name reference" to previous transaction that updated name
+		// Save this transaction, with updated "name reference" to previous transaction that updated name
 		this.repository.getTransactionRepository().save(cancelSellNameTransactionData);
 
 		// Update owner's balance
@@ -129,10 +129,10 @@ public class CancelSellNameTransaction extends Transaction {
 	public void orphan() throws DataException {
 		// Revert name
 		Name name = new Name(this.repository, cancelSellNameTransactionData.getName());
-		name.unsell(cancelSellNameTransactionData);
+		name.uncancelSell(cancelSellNameTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(cancelSellNameTransactionData);
+		// Save this transaction, with removed "name reference"
+		this.repository.getTransactionRepository().save(cancelSellNameTransactionData);
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/CreateAssetOrderTransaction.java

@@ -186,8 +186,7 @@ public class CreateAssetOrderTransaction extends Transaction {
 		// Update creator's last reference
 		creator.setLastReference(createOrderTransactionData.getSignature());
 
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(createOrderTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Order Id is transaction's signature
 		byte[] orderId = createOrderTransactionData.getSignature();
@@ -217,8 +216,7 @@ public class CreateAssetOrderTransaction extends Transaction {
 		OrderData orderData = this.repository.getAssetRepository().fromOrderId(orderId);
 		new Order(this.repository, orderData).orphan();
 
-		// Delete this transaction
-		this.repository.getTransactionRepository().delete(createOrderTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 	}
 
 }

src/main/java/org/qora/transaction/CreateGroupTransaction.java

@@ -139,8 +139,11 @@ public class CreateGroupTransaction extends Transaction {
 		Group group = new Group(this.repository, createGroupTransactionData.getGroupId());
 		group.uncreate();
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(createGroupTransactionData);
+		// Remove assigned group ID from transaction record
+		createGroupTransactionData.setGroupId(null);
+
+		// Save this transaction with removed group ID
+		this.repository.getTransactionRepository().save(createGroupTransactionData);
 
 		// Update creator's balance
 		Account creator = getCreator();

src/main/java/org/qora/transaction/CreatePollTransaction.java

@@ -153,8 +153,7 @@ public class CreatePollTransaction extends Transaction {
 		Poll poll = new Poll(this.repository, createPollTransactionData);
 		poll.publish();
 
-		// Save this transaction, now with corresponding pollId
-		this.repository.getTransactionRepository().save(createPollTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update creator's balance
 		Account creator = getCreator();
@@ -170,8 +169,7 @@ public class CreatePollTransaction extends Transaction {
 		Poll poll = new Poll(this.repository, createPollTransactionData.getPollName());
 		poll.unpublish();
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(createPollTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update creator's balance
 		Account creator = getCreator();

src/main/java/org/qora/transaction/DeployAtTransaction.java

@@ -216,8 +216,7 @@ public class DeployAtTransaction extends Transaction {
 		AT at = new AT(this.repository, this.deployATTransactionData);
 		at.deploy();
 
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		long assetId = deployATTransactionData.getAssetId();
 
@@ -243,8 +242,7 @@ public class DeployAtTransaction extends Transaction {
 		AT at = new AT(this.repository, this.deployATTransactionData);
 		at.undeploy();
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(deployATTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		long assetId = deployATTransactionData.getAssetId();
 

src/main/java/org/qora/transaction/EnableForgingTransaction.java

@@ -152,8 +152,7 @@ public class EnableForgingTransaction extends Transaction {
 		target.setFlags(targetFlags);
 		target.setForgingEnabler(creator.getAddress());
 
-		// Save this transaction
-		this.repository.getTransactionRepository().save(enableForgingTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update creator's balance
 		creator.setConfirmedBalance(Asset.QORA, creator.getConfirmedBalance(Asset.QORA).subtract(enableForgingTransactionData.getFee()));
@@ -182,8 +181,7 @@ public class EnableForgingTransaction extends Transaction {
 		target.setFlags(targetFlags);
 		target.setForgingEnabler(null);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(enableForgingTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update creator's balance
 		creator.setConfirmedBalance(Asset.QORA, creator.getConfirmedBalance(Asset.QORA).add(enableForgingTransactionData.getFee()));

src/main/java/org/qora/transaction/GenesisTransaction.java

@@ -136,8 +136,7 @@ public class GenesisTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		Account recipient = new Account(repository, genesisTransactionData.getRecipient());
 
@@ -150,8 +149,7 @@ public class GenesisTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction
-		this.repository.getTransactionRepository().delete(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Delete recipient's account (and balance)
 		this.repository.getAccountRepository().delete(genesisTransactionData.getRecipient());

src/main/java/org/qora/transaction/GroupApprovalTransaction.java

@@ -115,10 +115,9 @@ public class GroupApprovalTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Revert?
-
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(groupApprovalTransactionData);
+		// Save this transaction with removed prior reference
+		groupApprovalTransactionData.setPriorReference(null);
+		this.repository.getTransactionRepository().save(groupApprovalTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/GroupBanTransaction.java

@@ -135,8 +135,8 @@ public class GroupBanTransaction extends Transaction {
 		Group group = new Group(this.repository, groupBanTransactionData.getGroupId());
 		group.unban(groupBanTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(groupBanTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(groupBanTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/GroupInviteTransaction.java

@@ -141,8 +141,8 @@ public class GroupInviteTransaction extends Transaction {
 		Group group = new Group(this.repository, groupInviteTransactionData.getGroupId());
 		group.uninvite(groupInviteTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(groupInviteTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(groupInviteTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/GroupKickTransaction.java

@@ -141,8 +141,8 @@ public class GroupKickTransaction extends Transaction {
 		Group group = new Group(this.repository, groupKickTransactionData.getGroupId());
 		group.unkick(groupKickTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(groupKickTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(groupKickTransactionData);
 
 		// Update admin's balance
 		Account admin = getAdmin();

src/main/java/org/qora/transaction/IssueAssetTransaction.java

@@ -170,8 +170,11 @@ public class IssueAssetTransaction extends Transaction {
 		Asset asset = new Asset(this.repository, issueAssetTransactionData.getAssetId());
 		asset.deissue();
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(issueAssetTransactionData);
+		// Remove assigned asset ID from transaction info
+		issueAssetTransactionData.setAssetId(null);
+
+		// Save this transaction, with removed assetId
+		this.repository.getTransactionRepository().save(issueAssetTransactionData);
 
 		// Update issuer's balance
 		Account issuer = getIssuer();

src/main/java/org/qora/transaction/JoinGroupTransaction.java

@@ -104,7 +104,7 @@ public class JoinGroupTransaction extends Transaction {
 		Group group = new Group(this.repository, joinGroupTransactionData.getGroupId());
 		group.join(joinGroupTransactionData);
 
-		// Save this transaction
+		// Save this transaction with cached references to transactions that can help restore state
 		this.repository.getTransactionRepository().save(joinGroupTransactionData);
 
 		// Update joiner's balance
@@ -122,8 +122,8 @@ public class JoinGroupTransaction extends Transaction {
 		Group group = new Group(this.repository, joinGroupTransactionData.getGroupId());
 		group.unjoin(joinGroupTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(joinGroupTransactionData);
+		// Save this transaction with removed references
+		this.repository.getTransactionRepository().save(joinGroupTransactionData);
 
 		// Update joiner's balance
 		Account joiner = getJoiner();

src/main/java/org/qora/transaction/LeaveGroupTransaction.java

@@ -120,8 +120,8 @@ public class LeaveGroupTransaction extends Transaction {
 		Group group = new Group(this.repository, leaveGroupTransactionData.getGroupId());
 		group.unleave(leaveGroupTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(leaveGroupTransactionData);
+		// Save this transaction with removed member/admin references
+		this.repository.getTransactionRepository().save(leaveGroupTransactionData);
 
 		// Update leaver's balance
 		Account leaver = getLeaver();

src/main/java/org/qora/transaction/MessageTransaction.java

@@ -116,8 +116,7 @@ public class MessageTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Wrap and delegate payment processing to Payment class. Only update recipient's last reference if transferring QORA.
 		new Payment(this.repository).process(messageTransactionData.getSenderPublicKey(), getPaymentData(), messageTransactionData.getFee(),
@@ -126,12 +125,11 @@ public class MessageTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		// Wrap and delegate payment processing to Payment class. Only revert recipient's last reference if transferring QORA.
 		new Payment(this.repository).orphan(messageTransactionData.getSenderPublicKey(), getPaymentData(), messageTransactionData.getFee(),
 				messageTransactionData.getSignature(), messageTransactionData.getReference(), false);
+
+		// We would save updated transaction at this point, but it hasn't been modified
 	}
 
 }

src/main/java/org/qora/transaction/MultiPaymentTransaction.java

@@ -116,8 +116,7 @@ public class MultiPaymentTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Wrap and delegate payment processing to Payment class. Always update recipients' last references regardless of asset.
 		new Payment(this.repository).process(multiPaymentTransactionData.getSenderPublicKey(), multiPaymentTransactionData.getPayments(),
@@ -126,12 +125,11 @@ public class MultiPaymentTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		// Wrap and delegate payment processing to Payment class. Always revert recipients' last references regardless of asset.
 		new Payment(this.repository).orphan(multiPaymentTransactionData.getSenderPublicKey(), multiPaymentTransactionData.getPayments(),
 				multiPaymentTransactionData.getFee(), multiPaymentTransactionData.getSignature(), multiPaymentTransactionData.getReference(), true);
+
+		// We would save updated transaction at this point, but it hasn't been modified
 	}
 
 }

src/main/java/org/qora/transaction/PaymentTransaction.java

@@ -88,8 +88,7 @@ public class PaymentTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Wrap and delegate payment processing to Payment class. Only update recipient's last reference if transferring QORA.
 		new Payment(this.repository).process(paymentTransactionData.getSenderPublicKey(), getPaymentData(), paymentTransactionData.getFee(),
@@ -98,12 +97,11 @@ public class PaymentTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		// Wrap and delegate payment processing to Payment class. Only revert recipient's last reference if transferring QORA.
 		new Payment(this.repository).orphan(paymentTransactionData.getSenderPublicKey(), getPaymentData(), paymentTransactionData.getFee(),
 				paymentTransactionData.getSignature(), paymentTransactionData.getReference(), false);
+
+		// We would save updated transaction at this point, but it hasn't been modified
 	}
 
 }

src/main/java/org/qora/transaction/ProxyForgingTransaction.java

@@ -163,8 +163,9 @@ public class ProxyForgingTransaction extends Transaction {
 			this.repository.getAccountRepository().delete(forger.getPublicKey(), proxyForgingTransactionData.getRecipient());
 		}
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(proxyForgingTransactionData);
+		// Save this transaction, with removed previous share info
+		proxyForgingTransactionData.setPreviousShare(null);
+		this.repository.getTransactionRepository().save(proxyForgingTransactionData);
 
 		// Update forger's balance
 		forger.setConfirmedBalance(Asset.QORA, forger.getConfirmedBalance(Asset.QORA).add(proxyForgingTransactionData.getFee()));

src/main/java/org/qora/transaction/RegisterNameTransaction.java

@@ -125,8 +125,7 @@ public class RegisterNameTransaction extends Transaction {
 		Name name = new Name(this.repository, registerNameTransactionData);
 		name.register();
 
-		// Save this transaction
-		this.repository.getTransactionRepository().save(registerNameTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update registrant's balance
 		Account registrant = getRegistrant();
@@ -142,8 +141,7 @@ public class RegisterNameTransaction extends Transaction {
 		Name name = new Name(this.repository, registerNameTransactionData.getName());
 		name.unregister();
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(registerNameTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update registrant's balance
 		Account registrant = getRegistrant();

src/main/java/org/qora/transaction/RemoveGroupAdminTransaction.java

@@ -117,7 +117,7 @@ public class RemoveGroupAdminTransaction extends Transaction {
 		Group group = new Group(this.repository, removeGroupAdminTransactionData.getGroupId());
 		group.demoteFromAdmin(removeGroupAdminTransactionData);
 
-		// Save this transaction
+		// Save this transaction with cached references to transactions that can help restore state
 		this.repository.getTransactionRepository().save(removeGroupAdminTransactionData);
 
 		// Update owner's balance
@@ -134,8 +134,8 @@ public class RemoveGroupAdminTransaction extends Transaction {
 		Group group = new Group(this.repository, removeGroupAdminTransactionData.getGroupId());
 		group.undemoteFromAdmin(removeGroupAdminTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(removeGroupAdminTransactionData);
+		// Save this transaction with removed group references
+		this.repository.getTransactionRepository().save(removeGroupAdminTransactionData);
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/SellNameTransaction.java

@@ -118,12 +118,11 @@ public class SellNameTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Update Name
+		// Sell Name
 		Name name = new Name(this.repository, sellNameTransactionData.getName());
 		name.sell(sellNameTransactionData);
 
-		// Save this transaction, now with updated "name reference" to previous transaction that updated name
-		this.repository.getTransactionRepository().save(sellNameTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update owner's balance
 		Account owner = getOwner();
@@ -139,8 +138,7 @@ public class SellNameTransaction extends Transaction {
 		Name name = new Name(this.repository, sellNameTransactionData.getName());
 		name.unsell(sellNameTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(sellNameTransactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/SetGroupTransaction.java

@@ -119,8 +119,9 @@ public class SetGroupTransaction extends Transaction {
 
 		creator.setDefaultGroupId(previousDefaultGroupId);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(setGroupTransactionData);
+		// Save this transaction with removed previous defaultGroupId value
+		setGroupTransactionData.setPreviousDefaultGroupId(null);
+		this.repository.getTransactionRepository().save(setGroupTransactionData);
 
 		// Update creator's balance
 		creator.setConfirmedBalance(Asset.QORA, creator.getConfirmedBalance(Asset.QORA).add(setGroupTransactionData.getFee()));

src/main/java/org/qora/transaction/TransferAssetTransaction.java

@@ -101,8 +101,7 @@ public class TransferAssetTransaction extends Transaction {
 
 	@Override
 	public void process() throws DataException {
-		// Save this transaction itself
-		this.repository.getTransactionRepository().save(this.transactionData);
+		// We would save updated transaction at this point, but it hasn't been modified
 
 		// Wrap asset transfer as a payment and delegate processing to Payment class. Only update recipient's last reference if transferring QORA.
 		new Payment(this.repository).process(transferAssetTransactionData.getSenderPublicKey(), getPaymentData(), transferAssetTransactionData.getFee(),
@@ -111,12 +110,11 @@ public class TransferAssetTransaction extends Transaction {
 
 	@Override
 	public void orphan() throws DataException {
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(this.transactionData);
-
 		// Wrap asset transfer as a payment and delegate processing to Payment class. Only revert recipient's last reference if transferring QORA.
 		new Payment(this.repository).orphan(transferAssetTransactionData.getSenderPublicKey(), getPaymentData(), transferAssetTransactionData.getFee(),
 				transferAssetTransactionData.getSignature(), transferAssetTransactionData.getReference(), false);
+
+		// We would save updated transaction at this point, but it hasn't been modified
 	}
 
 }

src/main/java/org/qora/transaction/UpdateAssetTransaction.java

@@ -130,8 +130,7 @@ public class UpdateAssetTransaction extends Transaction {
 		Asset asset = new Asset(this.repository, updateAssetTransactionData.getAssetId());
 		asset.update(updateAssetTransactionData);
 
-		// Save this transaction, now with updated "name reference" to previous
-		// transaction that updated name
+		// Save this transaction, with updated "name reference" to previous transaction that updated name
 		this.repository.getTransactionRepository().save(updateAssetTransactionData);
 
 		// Update old owner's balance
@@ -149,8 +148,8 @@ public class UpdateAssetTransaction extends Transaction {
 		Asset asset = new Asset(this.repository, updateAssetTransactionData.getAssetId());
 		asset.revert(updateAssetTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(updateAssetTransactionData);
+		// Save this transaction, with removed "name reference" to previous transaction that updated name
+		this.repository.getTransactionRepository().save(updateAssetTransactionData);
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/UpdateGroupTransaction.java

@@ -149,8 +149,8 @@ public class UpdateGroupTransaction extends Transaction {
 		Group group = new Group(this.repository, updateGroupTransactionData.getGroupId());
 		group.unupdateGroup(updateGroupTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(updateGroupTransactionData);
+		// Save this transaction, now with removed "group reference"
+		this.repository.getTransactionRepository().save(updateGroupTransactionData);
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/UpdateNameTransaction.java

@@ -151,8 +151,8 @@ public class UpdateNameTransaction extends Transaction {
 		Name name = new Name(this.repository, updateNameTransactionData.getName());
 		name.revert(updateNameTransactionData);
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(updateNameTransactionData);
+		// Save this transaction, now with removed "name reference"
+		this.repository.getTransactionRepository().save(updateNameTransactionData);
 
 		// Update owner's balance
 		Account owner = getOwner();

src/main/java/org/qora/transaction/VoteOnPollTransaction.java

@@ -177,8 +177,9 @@ public class VoteOnPollTransaction extends Transaction {
 			votingRepository.delete(voteOnPollTransactionData.getPollName(), voteOnPollTransactionData.getVoterPublicKey());
 		}
 
-		// Delete this transaction itself
-		this.repository.getTransactionRepository().delete(voteOnPollTransactionData);
+		// Save this transaction, with removed previous vote info
+		voteOnPollTransactionData.setPreviousOptionIndex(null);
+		this.repository.getTransactionRepository().save(voteOnPollTransactionData);
 	}
 
 }