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| author | Michael Cahill <michael.cahill@mongodb.com> | 2015-11-24 16:05:25 +1100 |
|---|---|---|
| committer | Michael Cahill <michael.cahill@mongodb.com> | 2015-11-24 16:05:25 +1100 |
| commit | 0ba1737427565b679ea6a8dd43c4ca175dd3f613 (patch) | |
| tree | 1985908af2639307f59a8a2b64a852709270cfff /src/reconcile/rec_track.c | |
| parent | 2cf57a6fbfc220c704b5138bf3e71a439beedcaa (diff) | |
| download | mongo-0ba1737427565b679ea6a8dd43c4ca175dd3f613.tar.gz | |
WT-2237 Have threads publish unique transaction IDs so that updates always become visible immediately on commit.
Previously, WiredTiger avoided locking in the transaction subsystem by having
threads race to allocate transaction IDs. Only one thread wins the race, but
losing threads could temporarily leave a transaction ID published in the global
state table. If the winning thread completed its transaction quickly enough,
its changes may not become visible immediately to readers (until the losing
threads have woken up and allocated a new ID).
This change separates ID allocation from the notion of a shared "current"
value. Every thread gets a unique transaction ID, and spins to update the
current value.
Diffstat (limited to 'src/reconcile/rec_track.c')
| -rw-r--r-- | src/reconcile/rec_track.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/reconcile/rec_track.c b/src/reconcile/rec_track.c index 5d8870dc5ae..18ed5c6b551 100644 --- a/src/reconcile/rec_track.c +++ b/src/reconcile/rec_track.c @@ -820,7 +820,7 @@ __wt_ovfl_txnc_add(WT_SESSION_IMPL *session, WT_PAGE *page, txnc->value_offset = WT_PTRDIFF32(p, txnc); txnc->value_size = WT_STORE_SIZE(value_size); memcpy(p, value, value_size); - txnc->current = __wt_txn_new_id(session); + txnc->current = __wt_txn_id_alloc(session, false); __wt_cache_page_inmem_incr( session, page, WT_OVFL_SIZE(txnc, WT_OVFL_TXNC)); |