database/sql: use slices rather than container/list
Significantly reduces the number of allocations, while also
simplifying the code and increasing performance by a 1-2%.
benchmark old ns/op new ns/op delta
BenchmarkConcurrentDBExec 13290567 13026236 -1.99%
BenchmarkConcurrentStmtQuery 13249399 13008879 -1.82%
BenchmarkConcurrentStmtExec 8806237 8680182 -1.43%
BenchmarkConcurrentTxQuery 13628379 12756293 -6.40%
BenchmarkConcurrentTxExec 4794800 4722440 -1.51%
BenchmarkConcurrentTxStmtQuery 5040804 5200721 +3.17%
BenchmarkConcurrentTxStmtExec 1366574 1336626 -2.19%
BenchmarkConcurrentRandom 11119120 10926113 -1.74%
benchmark old allocs new allocs delta
BenchmarkConcurrentDBExec 14191 13684 -3.57%
BenchmarkConcurrentStmtQuery 16020 15514 -3.16%
BenchmarkConcurrentStmtExec 4179 3672 -12.13%
BenchmarkConcurrentTxQuery 16025 15518 -3.16%
BenchmarkConcurrentTxExec 12717 12709 -0.06%
BenchmarkConcurrentTxStmtQuery 15532 15525 -0.05%
BenchmarkConcurrentTxStmtExec 2175 2168 -0.32%
BenchmarkConcurrentRandom 12320 11997 -2.62%
benchmark old bytes new bytes delta
BenchmarkConcurrentDBExec 2164827 2139760 -1.16%
BenchmarkConcurrentStmtQuery 2418070 2394030 -0.99%
BenchmarkConcurrentStmtExec 1728782 1704371 -1.41%
BenchmarkConcurrentTxQuery 2477144 2452620 -0.99%
BenchmarkConcurrentTxExec 588920 588343 -0.10%
BenchmarkConcurrentTxStmtQuery 790866 796578 +0.72%
BenchmarkConcurrentTxStmtExec 98502 98143 -0.36%
BenchmarkConcurrentRandom 1725906 1710220 -0.91%
LGTM=ruiu, dave, bradfitz
R=golang-codereviews, ruiu, gobot, bradfitz, dave, minux
CC=bradfitz, golang-codereviews
https://golang.org/cl/107020044
diff --git a/src/pkg/database/sql/sql_test.go b/src/pkg/database/sql/sql_test.go
index 71c81d6..8849c81 100644
--- a/src/pkg/database/sql/sql_test.go
+++ b/src/pkg/database/sql/sql_test.go
@@ -24,7 +24,14 @@
}
freedFrom := make(map[dbConn]string)
putConnHook = func(db *DB, c *driverConn) {
- if c.listElem != nil {
+ idx := -1
+ for i, v := range db.freeConn {
+ if v == c {
+ idx = i
+ break
+ }
+ }
+ if idx >= 0 {
// print before panic, as panic may get lost due to conflicting panic
// (all goroutines asleep) elsewhere, since we might not unlock
// the mutex in freeConn here.
@@ -79,15 +86,14 @@
t.Errorf("Error closing fakeConn: %v", err)
}
})
- for node, i := db.freeConn.Front(), 0; node != nil; node, i = node.Next(), i+1 {
- dc := node.Value.(*driverConn)
+ for i, dc := range db.freeConn {
if n := len(dc.openStmt); n > 0 {
// Just a sanity check. This is legal in
// general, but if we make the tests clean up
// their statements first, then we can safely
// verify this is always zero here, and any
// other value is a leak.
- t.Errorf("while closing db, freeConn %d/%d had %d open stmts; want 0", i, db.freeConn.Len(), n)
+ t.Errorf("while closing db, freeConn %d/%d had %d open stmts; want 0", i, len(db.freeConn), n)
}
}
err := db.Close()
@@ -105,10 +111,10 @@
// numPrepares assumes that db has exactly 1 idle conn and returns
// its count of calls to Prepare
func numPrepares(t *testing.T, db *DB) int {
- if n := db.freeConn.Len(); n != 1 {
+ if n := len(db.freeConn); n != 1 {
t.Fatalf("free conns = %d; want 1", n)
}
- return (db.freeConn.Front().Value.(*driverConn)).ci.(*fakeConn).numPrepare
+ return db.freeConn[0].ci.(*fakeConn).numPrepare
}
func (db *DB) numDeps() int {
@@ -133,7 +139,7 @@
func (db *DB) numFreeConns() int {
db.mu.Lock()
defer db.mu.Unlock()
- return db.freeConn.Len()
+ return len(db.freeConn)
}
func (db *DB) dumpDeps(t *testing.T) {
@@ -650,10 +656,10 @@
if err != nil {
t.Fatal(err)
}
- if db.freeConn.Len() != 1 {
+ if len(db.freeConn) != 1 {
t.Fatalf("expected 1 free conn")
}
- fakeConn := (db.freeConn.Front().Value.(*driverConn)).ci.(*fakeConn)
+ fakeConn := db.freeConn[0].ci.(*fakeConn)
if made, closed := fakeConn.stmtsMade, fakeConn.stmtsClosed; made != closed {
t.Errorf("statement close mismatch: made %d, closed %d", made, closed)
}
@@ -878,13 +884,13 @@
t.Fatal(err)
}
tx.Commit()
- if got := db.freeConn.Len(); got != 1 {
+ if got := len(db.freeConn); got != 1 {
t.Errorf("freeConns = %d; want 1", got)
}
db.SetMaxIdleConns(0)
- if got := db.freeConn.Len(); got != 0 {
+ if got := len(db.freeConn); got != 0 {
t.Errorf("freeConns after set to zero = %d; want 0", got)
}
@@ -893,7 +899,7 @@
t.Fatal(err)
}
tx.Commit()
- if got := db.freeConn.Len(); got != 0 {
+ if got := len(db.freeConn); got != 0 {
t.Errorf("freeConns = %d; want 0", got)
}
}
@@ -1180,10 +1186,10 @@
t.Fatal(err)
}
- if db.freeConn.Len() != 1 {
- t.Fatalf("expected 1 freeConn; got %d", db.freeConn.Len())
+ if len(db.freeConn) != 1 {
+ t.Fatalf("expected 1 freeConn; got %d", len(db.freeConn))
}
- dc := db.freeConn.Front().Value.(*driverConn)
+ dc := db.freeConn[0]
if dc.closed {
t.Errorf("conn shouldn't be closed")
}
