schema change: epoch start_height is nullable

make epoch tracking parallelism-friendly

simplify db query; special-case end_height for current epoch

nit

analyzer/consensus/consensus.go

@@ -373,20 +373,11 @@ func (m *Main) queueBlockInserts(batch *storage.QueryBatch, data *storage.Consen
 
 func (m *Main) queueEpochInserts(batch *storage.QueryBatch, data *storage.ConsensusBlockData) error {
 	batch.Queue(
-		queries.ConsensusEpochInsert,
+		queries.ConsensusEpochUpsert,
 		data.Epoch,
 		data.BlockHeader.Height,
 	)
 
-	// Conclude previous epoch. Epochs start at index 0.
-	if data.Epoch > 0 {
-		batch.Queue(
-			queries.ConsensusEpochUpdate,
-			data.Epoch-1,
-			data.BlockHeader.Height,
-		)
-	}
-
 	return nil
 }
 

analyzer/queries/queries.go

@@ -27,15 +27,13 @@ const (
     INSERT INTO chain.blocks (height, block_hash, time, num_txs, namespace, version, type, root_hash)
       VALUES ($1, $2, $3, $4, $5, $6, $7, $8)`
 
-	ConsensusEpochInsert = `
-    INSERT INTO chain.epochs (id, start_height)
-      VALUES ($1, $2)
-    ON CONFLICT (id) DO NOTHING`
-
-	ConsensusEpochUpdate = `
-    UPDATE chain.epochs
-    SET end_height = $2
-      WHERE id = $1 AND end_height IS NULL`
+	ConsensusEpochUpsert = `
+    INSERT INTO chain.epochs AS epochs (id, start_height, end_height)
+      VALUES ($1, $2, $2)
+    ON CONFLICT (id) DO 
+    UPDATE SET
+      start_height = LEAST(excluded.start_height, epochs.start_height),
+      end_height = GREATEST(excluded.end_height, epochs.end_height)`
 
 	ConsensusTransactionInsert = `
     INSERT INTO chain.transactions (block, tx_hash, tx_index, nonce, fee_amount, max_gas, method, sender, body, module, code, message)

storage/client/queries/queries.go

@@ -180,7 +180,8 @@ const (
 		OFFSET $3::bigint`
 
 	Epochs = `
-		SELECT id, start_height, end_height
+		SELECT id, start_height, 
+			(CASE id WHEN (SELECT max(id) FROM chain.epochs) THEN NULL ELSE end_height END) AS end_height
 			FROM chain.epochs
 		ORDER BY id DESC
 		LIMIT $1::bigint

storage/migrations/01_consensus.up.sql

@@ -84,10 +84,13 @@ CREATE INDEX ix_events_type ON chain.events (type, tx_block);  -- tx_block is fo
 CREATE TABLE chain.epochs
 (
   id           UINT63 PRIMARY KEY,
+  -- Earliest known height that belongs to the epoch.
   start_height UINT63 NOT NULL,
-  end_height   UINT63 CHECK (end_height IS NULL OR end_height >= start_height),
+  -- Max known height that belongs to the epoch.
+  end_height   UINT63 CHECK (end_height >= start_height),
   UNIQUE (start_height, end_height)
 );
+CREATE INDEX ix_epochs_id ON chain.epochs (id);
 
 -- Registry Backend Data
 CREATE TABLE chain.entities