1 files changed, 20 insertions, 12 deletions
diff --git a/vendor/github.com/ncruces/go-sqlite3/internal/alloc/alloc_unix.go b/vendor/github.com/ncruces/go-sqlite3/internal/alloc/alloc_unix.go
index a00dbbf24..203d8471a 100644
--- a/vendor/github.com/ncruces/go-sqlite3/internal/alloc/alloc_unix.go
+++ b/vendor/github.com/ncruces/go-sqlite3/internal/alloc/alloc_unix.go
@@ -9,24 +9,31 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-func NewMemory(_, max uint64) experimental.LinearMemory {
+func NewMemory(cap, max uint64) experimental.LinearMemory {
 	// Round up to the page size.
 	rnd := uint64(unix.Getpagesize() - 1)
-	max = (max + rnd) &^ rnd
+	res := (max + rnd) &^ rnd
 
-	if max > math.MaxInt {
-		// This ensures int(max) overflows to a negative value,
+	if res > math.MaxInt {
+		// This ensures int(res) overflows to a negative value,
 		// and unix.Mmap returns EINVAL.
-		max = math.MaxUint64
+		res = math.MaxUint64
 	}
 
-	// Reserve max bytes of address space, to ensure we won't need to move it.
+	com := res
+	prot := unix.PROT_READ | unix.PROT_WRITE
+	if cap < max { // Commit memory only if cap=max.
+		com = 0
+		prot = unix.PROT_NONE
+	}
+
+	// Reserve res bytes of address space, to ensure we won't need to move it.
 	// A protected, private, anonymous mapping should not commit memory.
-	b, err := unix.Mmap(-1, 0, int(max), unix.PROT_NONE, unix.MAP_PRIVATE|unix.MAP_ANON)
+	b, err := unix.Mmap(-1, 0, int(res), prot, unix.MAP_PRIVATE|unix.MAP_ANON)
 	if err != nil {
 		panic(err)
 	}
-	return &mmappedMemory{buf: b[:0]}
+	return &mmappedMemory{buf: b[:com]}
 }
 
 // The slice covers the entire mmapped memory:
@@ -40,9 +47,11 @@ func (m *mmappedMemory) Reallocate(size uint64) []byte {
 	com := uint64(len(m.buf))
 	res := uint64(cap(m.buf))
 	if com < size && size <= res {
-		// Round up to the page size.
+		// Grow geometrically, round up to the page size.
 		rnd := uint64(unix.Getpagesize() - 1)
-		new := (size + rnd) &^ rnd
+		new := com + com>>3
+		new = min(max(size, new), res)
+		new = (new + rnd) &^ rnd
 
 		// Commit additional memory up to new bytes.
 		err := unix.Mprotect(m.buf[com:new], unix.PROT_READ|unix.PROT_WRITE)
@@ -50,8 +59,7 @@ func (m *mmappedMemory) Reallocate(size uint64) []byte {
 			return nil
 		}
 
-		// Update committed memory.
-		m.buf = m.buf[:new]
+		m.buf = m.buf[:new] // Update committed memory.
 	}
 	// Limit returned capacity because bytes beyond
 	// len(m.buf) have not yet been committed.