diff options
| author | sueloverso <sue@mongodb.com> | 2016-07-21 22:52:06 -0400 |
|---|---|---|
| committer | Alex Gorrod <alexander.gorrod@mongodb.com> | 2016-07-22 12:52:06 +1000 |
| commit | a5f696c394815e3d630b77187899670b8087da37 (patch) | |
| tree | 0ef1005922d18e5e02e72abb371aee6cf8c3a15d /src/lsm | |
| parent | c74fcf400168930c3f0f9f39f5ec30a06a01f2df (diff) | |
| download | mongo-a5f696c394815e3d630b77187899670b8087da37.tar.gz | |
WT-2239 Make sure LSM cursors read up to date dsk_gen, it was racing with compact. (#2895)
Diffstat (limited to 'src/lsm')
| -rw-r--r-- | src/lsm/lsm_cursor.c | 6 | ||||
| -rw-r--r-- | src/lsm/lsm_tree.c | 14 |
2 files changed, 19 insertions, 1 deletions
diff --git a/src/lsm/lsm_cursor.c b/src/lsm/lsm_cursor.c index 0fb917e8f4c..a0e636768f0 100644 --- a/src/lsm/lsm_cursor.c +++ b/src/lsm/lsm_cursor.c @@ -205,6 +205,12 @@ __clsm_enter(WT_CURSOR_LSM *clsm, bool reset, bool update) WT_RET(__wt_txn_id_check(session)); WT_RET(__clsm_enter_update(clsm)); + /* + * Switching the tree will update the generation before + * updating the switch transaction. We test the + * transaction in clsm_enter_update. Now test the + * disk generation to avoid races. + */ if (clsm->dsk_gen != clsm->lsm_tree->dsk_gen) goto open; diff --git a/src/lsm/lsm_tree.c b/src/lsm/lsm_tree.c index da106ae2089..2ecfb614eee 100644 --- a/src/lsm/lsm_tree.c +++ b/src/lsm/lsm_tree.c @@ -771,6 +771,11 @@ __wt_lsm_tree_switch(WT_SESSION_IMPL *session, WT_LSM_TREE *lsm_tree) ++lsm_tree->dsk_gen; lsm_tree->modified = true; + /* + * Ensure the updated disk generation is visible to all other threads + * before updating the transaction ID. + */ + WT_FULL_BARRIER(); /* * Set the switch transaction in the previous chunk unless this is @@ -1187,8 +1192,15 @@ __wt_lsm_compact(WT_SESSION_IMPL *session, const char *name, bool *skipp) */ if (lsm_tree->nchunks > 0 && (chunk = lsm_tree->chunk[lsm_tree->nchunks - 1]) != NULL) { - if (chunk->switch_txn == WT_TXN_NONE) + if (chunk->switch_txn == WT_TXN_NONE) { + /* + * Make sure any cursors open on the tree see the + * new switch generation before updating. + */ + ++lsm_tree->dsk_gen; + WT_FULL_BARRIER(); chunk->switch_txn = __wt_txn_id_alloc(session, false); + } /* * If we have a chunk, we want to look for it to be on-disk. * So we need to add a reference to keep it available. |