leverage height index on windows query

decred · Aug 12, 2019 · f243570 · f243570
1 parent 92b2bbc
commit f243570
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Showing 3 changed files with 10 additions and 5 deletions.
diff --git a/db/dcrpg/internal/blockstmts.go b/db/dcrpg/internal/blockstmts.go
@@ -133,9 +133,9 @@ const (
 		MIN(time) AS time,
 		COUNT(*) AS blocks_count
 		FROM blocks
+		WHERE height BETWEEN $2 AND $3
 		GROUP BY window_start
-		ORDER BY window_start DESC
-		LIMIT $2 OFFSET $3;`
+		ORDER BY window_start DESC;`
 
 	SelectBlocksTimeListingByLimit = `SELECT date_trunc($1, time) as index_value,
 		MAX(height),

diff --git a/db/dcrpg/pgblockchain.go b/db/dcrpg/pgblockchain.go
@@ -1628,7 +1628,8 @@ func (pgb *ChainDB) TicketPoolByDateAndInterval(maturityBlock int64,
 func (pgb *ChainDB) PosIntervals(limit, offset uint64) ([]*dbtypes.BlocksGroupedInfo, error) {
 	ctx, cancel := context.WithTimeout(pgb.ctx, pgb.queryTimeout)
 	defer cancel()
-	bgi, err := retrieveWindowBlocks(ctx, pgb.db, pgb.chainParams.StakeDiffWindowSize, limit, offset)
+	bgi, err := retrieveWindowBlocks(ctx, pgb.db,
+		pgb.chainParams.StakeDiffWindowSize, pgb.Height(), limit, offset)
 	return bgi, pgb.replaceCancelError(err)
 }
 

diff --git a/db/dcrpg/queries.go b/db/dcrpg/queries.go
@@ -1019,8 +1019,12 @@ func RetrieveAllVotesDbIDsHeightsTicketDbIDs(ctx context.Context, db *sql.DB) (i
 
 // retrieveWindowBlocks fetches chunks of windows using the limit and offset provided
 // for a window size of chaincfg.Params.StakeDiffWindowSize.
-func retrieveWindowBlocks(ctx context.Context, db *sql.DB, windowSize int64, limit, offset uint64) ([]*dbtypes.BlocksGroupedInfo, error) {
-	rows, err := db.QueryContext(ctx, internal.SelectWindowsByLimit, windowSize, limit, offset)
+func retrieveWindowBlocks(ctx context.Context, db *sql.DB, windowSize, currentHeight int64, limit, offset uint64) ([]*dbtypes.BlocksGroupedInfo, error) {
+	endWindow := currentHeight/windowSize - int64(offset)
+	startWindow := endWindow - int64(limit) + 1
+	startHeight := startWindow * windowSize
+	endHeight := (endWindow+1)*windowSize - 1
+	rows, err := db.QueryContext(ctx, internal.SelectWindowsByLimit, windowSize, startHeight, endHeight)
 	if err != nil {
 		return nil, fmt.Errorf("retrieveWindowBlocks failed: error: %v", err)
 	}