diff options
Diffstat (limited to 'src/third_party/wiredtiger/src/txn/txn_timestamp.c')
| -rw-r--r-- | src/third_party/wiredtiger/src/txn/txn_timestamp.c | 58 |
1 files changed, 44 insertions, 14 deletions
diff --git a/src/third_party/wiredtiger/src/txn/txn_timestamp.c b/src/third_party/wiredtiger/src/txn/txn_timestamp.c index 385817e89b9..b50da548f71 100644 --- a/src/third_party/wiredtiger/src/txn/txn_timestamp.c +++ b/src/third_party/wiredtiger/src/txn/txn_timestamp.c @@ -132,6 +132,20 @@ __wt_txn_parse_timestamp(WT_SESSION_IMPL *session, const char *name, } /* + * __txn_get_read_timestamp -- + * Get the read timestamp from the transaction. Additionally + * return bool to specify whether the transaction has set + * clear read queue flag. + */ +static bool +__txn_get_read_timestamp( + WT_TXN *txn, wt_timestamp_t *read_timestampp) +{ + WT_ORDERED_READ(*read_timestampp, txn->read_timestamp); + return (!txn->clear_read_q); +} + +/* * __txn_get_pinned_timestamp -- * Calculate the current pinned timestamp. */ @@ -142,7 +156,7 @@ __txn_get_pinned_timestamp( WT_CONNECTION_IMPL *conn; WT_TXN *txn; WT_TXN_GLOBAL *txn_global; - wt_timestamp_t tmp_ts; + wt_timestamp_t tmp_read_ts, tmp_ts; bool include_oldest, txn_has_write_lock; conn = S2C(session); @@ -171,15 +185,18 @@ __txn_get_pinned_timestamp( TAILQ_FOREACH(txn, &txn_global->read_timestamph, read_timestampq) { /* * Skip any transactions on the queue that are not active. + * Copy out value of read timestamp to prevent possible + * race where a transaction resets its read timestamp while + * we traverse the queue. */ - if (txn->clear_read_q) + if (!__txn_get_read_timestamp(txn, &tmp_read_ts)) continue; /* * A zero timestamp is possible here only when the oldest * timestamp is not accounted for. */ - if (tmp_ts == 0 || txn->read_timestamp < tmp_ts) - tmp_ts = txn->read_timestamp; + if (tmp_ts == 0 || tmp_read_ts < tmp_ts) + tmp_ts = tmp_read_ts; /* * We break on the first active txn on the list. */ @@ -239,6 +256,13 @@ __txn_global_query_timestamp( break; } __wt_readunlock(session, &txn_global->commit_timestamp_rwlock); + + /* + * If a transaction is committing with timestamp 1, we could + * return zero here, which is unexpected. Fail instead. + */ + if (ts == 0) + return (WT_NOTFOUND); } else if (WT_STRING_MATCH("last_checkpoint", cval.str, cval.len)) /* Read-only value forever. No lock needed. */ ts = txn_global->last_ckpt_timestamp; @@ -679,7 +703,7 @@ __wt_txn_parse_prepare_timestamp( WT_CONFIG_ITEM cval; WT_TXN *prev; WT_TXN_GLOBAL *txn_global; - wt_timestamp_t oldest_ts; + wt_timestamp_t oldest_ts, tmp_timestamp; char hex_timestamp[WT_TS_HEX_SIZE]; txn_global = &S2C(session)->txn_global; @@ -706,12 +730,12 @@ __wt_txn_parse_prepare_timestamp( /* * Skip any transactions that are not active. */ - if (prev->clear_read_q) { + if (!__txn_get_read_timestamp(prev, &tmp_timestamp)) { prev = TAILQ_PREV( prev, __wt_txn_rts_qh, read_timestampq); continue; } - if (prev->read_timestamp >= *timestamp) { + if (tmp_timestamp >= *timestamp) { __wt_readunlock(session, &txn_global->read_timestamp_rwlock); __wt_timestamp_to_hex_string( @@ -972,6 +996,7 @@ __wt_txn_set_read_timestamp(WT_SESSION_IMPL *session) { WT_TXN *qtxn, *txn, *txn_tmp; WT_TXN_GLOBAL *txn_global; + wt_timestamp_t tmp_timestamp; uint64_t walked; txn = &session->txn; @@ -1023,11 +1048,14 @@ __wt_txn_set_read_timestamp(WT_SESSION_IMPL *session) */ qtxn = TAILQ_LAST( &txn_global->read_timestamph, __wt_txn_rts_qh); - while (qtxn != NULL && - qtxn->read_timestamp > txn->read_timestamp) { - ++walked; - qtxn = TAILQ_PREV( - qtxn, __wt_txn_rts_qh, read_timestampq); + while (qtxn != NULL) { + if (!__txn_get_read_timestamp(qtxn, &tmp_timestamp) || + tmp_timestamp > txn->read_timestamp) { + ++walked; + qtxn = TAILQ_PREV(qtxn, + __wt_txn_rts_qh, read_timestampq); + } else + break; } if (qtxn == NULL) { TAILQ_INSERT_HEAD(&txn_global->read_timestamph, @@ -1061,9 +1089,10 @@ __wt_txn_clear_read_timestamp(WT_SESSION_IMPL *session) txn = &session->txn; - if (!F_ISSET(txn, WT_TXN_PUBLIC_TS_READ)) + if (!F_ISSET(txn, WT_TXN_PUBLIC_TS_READ)) { + txn->read_timestamp = WT_TS_NONE; return; - + } #ifdef HAVE_DIAGNOSTIC { WT_TXN_GLOBAL *txn_global; @@ -1084,6 +1113,7 @@ __wt_txn_clear_read_timestamp(WT_SESSION_IMPL *session) */ WT_PUBLISH(txn->clear_read_q, true); WT_PUBLISH(txn->flags, flags); + txn->read_timestamp = WT_TS_NONE; } /* |