From 522043366c6e60fc92776c09658a20b7e22ac120 Mon Sep 17 00:00:00 2001
From: Ben Johnson <benbjohnson@yahoo.com>
Date: Fri, 19 Feb 2016 09:18:07 -0700
Subject: use tx.meta during Tx.WriteTo()

This commit changes `Tx.WriteTo()` to use the transaction's
in-memory meta page instead of copying from the disk. This is
needed because the transaction uses the size from its meta page
but writes the current meta page on disk which may have allocated
additional pages since the transaction started.

Fixes #513
---
 tx.go | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

(limited to 'tx.go')

diff --git a/tx.go b/tx.go
index e74d2ca..299c073 100644
--- a/tx.go
+++ b/tx.go
@@ -297,12 +297,34 @@ func (tx *Tx) WriteTo(w io.Writer) (n int64, err error) {
 	}
 	defer func() { _ = f.Close() }()
 
-	// Copy the meta pages.
-	tx.db.metalock.Lock()
-	n, err = io.CopyN(w, f, int64(tx.db.pageSize*2))
-	tx.db.metalock.Unlock()
+	// Generate a meta page. We use the same page data for both meta pages.
+	buf := make([]byte, tx.db.pageSize)
+	page := (*page)(unsafe.Pointer(&buf[0]))
+	page.flags = metaPageFlag
+	*page.meta() = *tx.meta
+
+	// Write meta 0.
+	page.id = 0
+	page.meta().checksum = page.meta().sum64()
+	nn, err := w.Write(buf)
+	n += int64(nn)
+	if err != nil {
+		return n, fmt.Errorf("meta 0 copy: %s", err)
+	}
+
+	// Write meta 1 with a lower transaction id.
+	page.id = 1
+	page.meta().txid -= 1
+	page.meta().checksum = page.meta().sum64()
+	nn, err = w.Write(buf)
+	n += int64(nn)
 	if err != nil {
-		return n, fmt.Errorf("meta copy: %s", err)
+		return n, fmt.Errorf("meta 1 copy: %s", err)
+	}
+
+	// Move past the meta pages in the file.
+	if _, err := f.Seek(int64(tx.db.pageSize*2), os.SEEK_SET); err != nil {
+		return n, fmt.Errorf("seek: %s", err)
 	}
 
 	// Copy data pages.
-- 
cgit v1.2.3


From 37e96de68dcc7f3ee75e2a96410b2688553d9b82 Mon Sep 17 00:00:00 2001
From: Ben Johnson <benbjohnson@yahoo.com>
Date: Mon, 21 Mar 2016 08:49:39 -0600
Subject: fix strict mode

This commits fixes a timing bug where `DB.StrictMode` can panic
before the goroutine reading the database can finish. If an error
is found in strict mode then it now finishes reading the entire
database before panicking.
---
 tx.go | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

(limited to 'tx.go')

diff --git a/tx.go b/tx.go
index 299c073..b8510fd 100644
--- a/tx.go
+++ b/tx.go
@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 	"sort"
+	"strings"
 	"time"
 	"unsafe"
 )
@@ -202,8 +203,17 @@ func (tx *Tx) Commit() error {
 	// If strict mode is enabled then perform a consistency check.
 	// Only the first consistency error is reported in the panic.
 	if tx.db.StrictMode {
-		if err, ok := <-tx.Check(); ok {
-			panic("check fail: " + err.Error())
+		ch := tx.Check()
+		var errs []string
+		for {
+			err, ok := <-ch
+			if !ok {
+				break
+			}
+			errs = append(errs, err.Error())
+		}
+		if len(errs) > 0 {
+			panic("check fail: " + strings.Join(errs, "\n"))
 		}
 	}
 
-- 
cgit v1.2.3