Merge pull request #64 from itzmeanjan/fix-block-insertion

Conflicting Block Entry Resolution

Author: itzmeanjan

app/db/block.go

@@ -45,21 +45,16 @@ func StoreBlock(dbWOTx *gorm.DB, block *PackedBlock, status *d.StatusHolder, que
 
 			log.Printf("[!] Block %d already present in DB, similar ❌\n", block.Block.Number)
 
-			// -- If block is going to be updated, it's better
-			// we also remove associated entries for that block
-			// i.e. transactions, events
-			if err := RemoveEventsByBlockHash(dbWTx, persistedBlock.Hash); err != nil {
+			// cascaded deletion !
+			if err := DeleteBlock(dbWTx, block.Block.Number); err != nil {
 				return err
 			}
 
-			if err := RemoveTransactionsByBlockHash(dbWTx, persistedBlock.Hash); err != nil {
+			if err := PutBlock(dbWTx, block.Block); err != nil {
 				return err
 			}
-			// -- block data clean up ends here
 
-			if err := UpdateBlock(dbWTx, block.Block); err != nil {
-				return err
-			}
+			blockInserted = true
 
 		} else {
 
@@ -128,6 +123,12 @@ func PutBlock(dbWTx *gorm.DB, block *Blocks) error {
 
 }
 
+// DeleteBlock - Delete block entry, identified by block number, while
+// cascading all dependent entries ( i.e. in transactions/ events table )
+func DeleteBlock(dbWTx *gorm.DB, number uint64) error {
+	return dbWTx.Where("number = ?", number).Delete(&Blocks{}).Error
+}
+
 // UpdateBlock - Updating already existing block
 func UpdateBlock(dbWTx *gorm.DB, block *Blocks) error {
 

app/db/model.go

@@ -31,8 +31,8 @@ type Blocks struct {
 	TransactionRootHash string       `gorm:"column:txroothash;type:char(66);not null"`
 	ReceiptRootHash     string       `gorm:"column:receiptroothash;type:char(66);not null"`
 	ExtraData           []byte       `gorm:"column:extradata;type:bytea"`
-	Transactions        Transactions `gorm:"foreignKey:blockhash"`
-	Events              Events       `gorm:"foreignKey:blockhash"`
+	Transactions        Transactions `gorm:"foreignKey:blockhash;constraint:OnDelete:CASCADE;"`
+	Events              Events       `gorm:"foreignKey:blockhash;constraint:OnDelete:CASCADE;"`
 }
 
 // TableName - Overriding default table name
@@ -73,7 +73,7 @@ type Transactions struct {
 	Nonce     uint64 `gorm:"column:nonce;type:bigint;not null;index"`
 	State     uint64 `gorm:"column:state;type:smallint;not null"`
 	BlockHash string `gorm:"column:blockhash;type:char(66);not null;index"`
-	Events    Events `gorm:"foreignKey:txhash"`
+	Events    Events `gorm:"foreignKey:txhash;constraint:OnDelete:CASCADE;"`
 }
 
 // TableName - Overriding default table name

db/schema.sql

@@ -36,7 +36,7 @@ create table transactions (
     nonce bigint not null,
     state smallint not null,
     blockhash char(66) not null,
-    foreign key (blockhash) references blocks(hash)
+    foreign key (blockhash) references blocks(hash) on delete cascade
 );
 
 create index on transactions(from);
@@ -53,8 +53,8 @@ create table events (
     txhash char(66) not null,
     blockhash char(66) not null,
     primary key (blockhash, index),
-    foreign key (txhash) references transactions(hash),
-    foreign key (blockhash) references blocks(hash)
+    foreign key (txhash) references transactions(hash) on delete cascade,
+    foreign key (blockhash) references blocks(hash) on delete cascade
 );
 
 create index on events(origin);
@@ -75,7 +75,7 @@ create table delivery_history (
     client char(42) not null,
     ts timestamp not null,
     endpoint varchar(100) not null,
-    datalength bigint not null,
+    datalength bigint not null
 );
 
 create index on delivery_history(client);