func (pgSQL *pgSQL) FindLayer(name string, withFeatures, withVulnerabilities bool) (database.Layer, error) {
subquery := "all"
if withFeatures {
subquery += "/features"
} else if withVulnerabilities {
subquery += "/features+vulnerabilities"
}
defer observeQueryTime("FindLayer", subquery, time.Now())
// Find the layer
var layer database.Layer
var parentID zero.Int
var parentName zero.String
var namespaceID zero.Int
var namespaceName sql.NullString
t := time.Now()
err := pgSQL.QueryRow(searchLayer, name).
Scan(&layer.ID, &layer.Name, &layer.EngineVersion, &parentID, &parentName, &namespaceID,
&namespaceName)
observeQueryTime("FindLayer", "searchLayer", t)
if err != nil {
return layer, handleError("searchLayer", err)
}
if !parentID.IsZero() {
layer.Parent = &database.Layer{
Model: database.Model{ID: int(parentID.Int64)},
Name: parentName.String,
}
}
if !namespaceID.IsZero() {
layer.Namespace = &database.Namespace{
Model: database.Model{ID: int(namespaceID.Int64)},
Name: namespaceName.String,
}
}
// Find its features
if withFeatures || withVulnerabilities {
// Create a transaction to disable hash/merge joins as our experiments have shown that
// PostgreSQL 9.4 makes bad planning decisions about:
// - joining the layer tree to feature versions and feature
// - joining the feature versions to affected/fixed feature version and vulnerabilities
// It would for instance do a merge join between affected feature versions (300 rows, estimated
// 3000 rows) and fixed in feature version (100k rows). In this case, it is much more
// preferred to use a nested loop.
tx, err := pgSQL.Begin()
if err != nil {
return layer, handleError("FindLayer.Begin()", err)
}
defer tx.Commit()
_, err = tx.Exec(disableHashJoin)
if err != nil {
log.Warningf("FindLayer: could not disable hash join: %s", err)
}
_, err = tx.Exec(disableMergeJoin)
if err != nil {
log.Warningf("FindLayer: could not disable merge join: %s", err)
}
t = time.Now()
featureVersions, err := getLayerFeatureVersions(tx, layer.ID)
observeQueryTime("FindLayer", "getLayerFeatureVersions", t)
if err != nil {
return layer, err
}
layer.Features = featureVersions
if withVulnerabilities {
// Load the vulnerabilities that affect the FeatureVersions.
t = time.Now()
err := loadAffectedBy(tx, layer.Features)
observeQueryTime("FindLayer", "loadAffectedBy", t)
if err != nil {
return layer, err
}
}
}
return layer, nil
}
