database/sql: fix double decrement of numOpen count; test for connection leaks
Add a check at the end of every test to make sure
there are no leaked connections after running a test.
Avoid incorrectly decrementing the number of open connections
when the driver connection ends up it a bad state (numOpen was
decremented twice).
Prevent leaking a Rows struct (which ends up leaking a
connection) in Row.Scan() when a *RawBytes destination is
improperly used.
Close the Rows struct in TestRowsColumns.
Update #6593
R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/14642044
diff --git a/src/pkg/database/sql/sql.go b/src/pkg/database/sql/sql.go
index ae313ca..fe46ff3 100644
--- a/src/pkg/database/sql/sql.go
+++ b/src/pkg/database/sql/sql.go
@@ -504,7 +504,6 @@
// If n <= 0, no idle connections are retained.
func (db *DB) SetMaxIdleConns(n int) {
db.mu.Lock()
- defer db.mu.Unlock()
if n > 0 {
db.maxIdle = n
} else {
@@ -515,11 +514,16 @@
if db.maxOpen > 0 && db.maxIdleConnsLocked() > db.maxOpen {
db.maxIdle = db.maxOpen
}
+ var closing []*driverConn
for db.freeConn.Len() > db.maxIdleConnsLocked() {
dc := db.freeConn.Back().Value.(*driverConn)
dc.listElem = nil
db.freeConn.Remove(db.freeConn.Back())
- go dc.Close()
+ closing = append(closing, dc)
+ }
+ db.mu.Unlock()
+ for _, c := range closing {
+ c.Close()
}
}
@@ -743,8 +747,8 @@
if err == driver.ErrBadConn {
// Don't reuse bad connections.
// Since the conn is considered bad and is being discarded, treat it
- // as closed. Decrement the open count.
- db.numOpen--
+ // as closed. Don't decrement the open count here, finalClose will
+ // take care of that.
db.maybeOpenNewConnections()
db.mu.Unlock()
dc.Close()
@@ -1607,13 +1611,13 @@
// from Next will not be modified again." (for instance, if
// they were obtained from the network anyway) But for now we
// don't care.
+ defer r.rows.Close()
for _, dp := range dest {
if _, ok := dp.(*RawBytes); ok {
return errors.New("sql: RawBytes isn't allowed on Row.Scan")
}
}
- defer r.rows.Close()
if !r.rows.Next() {
return ErrNoRows
}
