From 5432949c4f9bf536b3932d7cc9b0186461316009 Mon Sep 17 00:00:00 2001
From: Michael Cahill <michael.cahill@wiredtiger.com>
Date: Tue, 14 May 2013 11:12:15 +1000
Subject: Fix an off-by-one error in the transaction used for eviction.  We
 track the oldest ID that can *not* be written.

---
 src/btree/bt_evict.c |  8 ++++++++
 src/txn/txn.c        | 11 +++++++----
 2 files changed, 15 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/btree/bt_evict.c b/src/btree/bt_evict.c
index 3bbc31e1582..a81c65a1ecd 100644
--- a/src/btree/bt_evict.c
+++ b/src/btree/bt_evict.c
@@ -333,6 +333,14 @@ __wt_evict_page(WT_SESSION_IMPL *session, WT_PAGE *page)
 
 	__wt_txn_get_evict_snapshot(session);
 	txn->isolation = TXN_ISO_READ_COMMITTED;
+
+	/*
+	 * Sanity check: if a transaction is running, its updates should not
+	 * be visible to eviction.
+	 */
+	WT_ASSERT(session, !was_running ||
+	    !__wt_txn_visible(session, saved_txn.id));
+
 	ret = __wt_rec_evict(session, page, 0);
 
 	if (was_running) {
diff --git a/src/txn/txn.c b/src/txn/txn.c
index c1a72ecd671..587983bc14e 100644
--- a/src/txn/txn.c
+++ b/src/txn/txn.c
@@ -168,9 +168,14 @@ __wt_txn_get_evict_snapshot(WT_SESSION_IMPL *session)
 
 	txn = &session->txn;
 
+	/*
+	 * The oldest active snapshot ID in the system should *not* be visible
+	 * to eviction.  Create a snapshot containing that ID.
+	 */
 	__wt_txn_get_oldest(session);
+	txn->snapshot[0] = txn->oldest_snap_min;
 	__txn_sort_snapshot(
-	    session, 0, txn->oldest_snap_min, txn->oldest_snap_min);
+	    session, 1, txn->oldest_snap_min, txn->oldest_snap_min);
 
 	/*
 	 * Note that we carefully don't update the global table with this
@@ -397,9 +402,7 @@ __wt_txn_init(WT_SESSION_IMPL *session)
 	txn->mod = NULL;
 	txn->modref = NULL;
 
-	/* The default isolation level is read-committed. */
-	txn->isolation = session->isolation = TXN_ISO_READ_COMMITTED;
-
+	txn->isolation = session->isolation;
 	return (0);
 }
 
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