indexer: Cache scanner table

During the indexing cycle many operations try to read information
from the scanner table, this can occasionally lead to resource
contention depending on the DB. This reads the table into memory when
the indexer store is instanciated and uses when asked for scanner info.

Signed-off-by: crozzy <[email protected]>

Author: crozzy

datastore/postgres/distributionsbylayer.go

@@ -39,13 +39,6 @@ var (
 
 func (s *IndexerStore) DistributionsByLayer(ctx context.Context, hash claircore.Digest, scnrs indexer.VersionedScanners) ([]*claircore.Distribution, error) {
 	const (
-		selectScanner = `
-		SELECT id
-		FROM scanner
-		WHERE name = $1
-		  AND version = $2
-		  AND kind = $3;
-		`
 		query = `
 		SELECT dist.id,
 			   dist.name,
@@ -68,17 +61,9 @@ func (s *IndexerStore) DistributionsByLayer(ctx context.Context, hash claircore.
 		return []*claircore.Distribution{}, nil
 	}
 
-	// get scanner ids
-	scannerIDs := make([]int64, len(scnrs))
-	for i, scnr := range scnrs {
-		start := time.Now()
-		err := s.pool.QueryRow(ctx, selectScanner, scnr.Name(), scnr.Version(), scnr.Kind()).
-			Scan(&scannerIDs[i])
-		if err != nil {
-			return nil, fmt.Errorf("failed to retrieve distribution ids for scanner %q: %w", scnr, err)
-		}
-		distributionByLayerCounter.WithLabelValues("selectScanner").Add(1)
-		distributionByLayerDuration.WithLabelValues("selectScanner").Observe(time.Since(start).Seconds())
+	scannerIDs, err := s.selectScanners(scnrs)
+	if err != nil {
+		return nil, err
 	}
 
 	start := time.Now()

datastore/postgres/filesbylayer.go

@@ -38,13 +38,6 @@ var (
 
 func (s *IndexerStore) FilesByLayer(ctx context.Context, hash claircore.Digest, scnrs indexer.VersionedScanners) ([]claircore.File, error) {
 	const (
-		selectScanner = `
-		SELECT id
-		FROM scanner
-		WHERE name = $1
-		  AND version = $2
-		  AND kind = $3;
-		`
 		query = `
 		SELECT file.path, file.kind
 		FROM file_scanartifact
@@ -59,17 +52,9 @@ func (s *IndexerStore) FilesByLayer(ctx context.Context, hash claircore.Digest,
 		return []claircore.File{}, nil
 	}
 
-	// get scanner ids
-	scannerIDs := make([]int64, len(scnrs))
-	for i, scnr := range scnrs {
-		start := time.Now()
-		err := s.pool.QueryRow(ctx, selectScanner, scnr.Name(), scnr.Version(), scnr.Kind()).
-			Scan(&scannerIDs[i])
-		filesByLayerCounter.WithLabelValues("selectScanner").Add(1)
-		filesByLayerDuration.WithLabelValues("selectScanner").Observe(time.Since(start).Seconds())
-		if err != nil {
-			return nil, fmt.Errorf("failed to retrieve file ids for scanner %q: %w", scnr, err)
-		}
+	scannerIDs, err := s.selectScanners(scnrs)
+	if err != nil {
+		return nil, err
 	}
 
 	start := time.Now()