diff options
Diffstat (limited to 'src/third_party/wiredtiger/src/include/btree.i')
| -rw-r--r-- | src/third_party/wiredtiger/src/include/btree.i | 118 |
1 files changed, 24 insertions, 94 deletions
diff --git a/src/third_party/wiredtiger/src/include/btree.i b/src/third_party/wiredtiger/src/include/btree.i index 81c166eb0e4..7813f1299fd 100644 --- a/src/third_party/wiredtiger/src/include/btree.i +++ b/src/third_party/wiredtiger/src/include/btree.i @@ -1158,8 +1158,7 @@ __wt_ref_block_free(WT_SESSION_IMPL *session, WT_REF *ref) * Return if a truncate operation is active. */ static inline bool -__wt_page_del_active( - WT_SESSION_IMPL *session, WT_REF *ref, bool visible_all) +__wt_page_del_active(WT_SESSION_IMPL *session, WT_REF *ref, bool visible_all) { WT_PAGE_DELETED *page_del; uint8_t prepare_state; @@ -1190,10 +1189,10 @@ __wt_page_las_active(WT_SESSION_IMPL *session, WT_REF *ref) if ((page_las = ref->page_las) == NULL) return (false); - if (page_las->invalid || !ref->page_las->las_skew_newest) + if (page_las->invalid || !ref->page_las->skew_newest) return (true); - if (__wt_txn_visible_all(session, page_las->las_max_txn, - WT_TIMESTAMP_NULL(&page_las->onpage_timestamp))) + if (__wt_txn_visible_all(session, page_las->max_txn, + WT_TIMESTAMP_NULL(&page_las->max_timestamp))) return (false); return (true); @@ -1329,6 +1328,7 @@ __wt_leaf_page_can_split(WT_SESSION_IMPL *session, WT_PAGE *page) static inline bool __wt_page_evict_retry(WT_SESSION_IMPL *session, WT_PAGE *page) { + WT_DECL_TIMESTAMP(pinned_ts) WT_PAGE_MODIFY *mod; WT_TXN_GLOBAL *txn_global; @@ -1338,7 +1338,8 @@ __wt_page_evict_retry(WT_SESSION_IMPL *session, WT_PAGE *page) * If the page hasn't been through one round of update/restore, give it * a try. */ - if ((mod = page->modify) == NULL || !mod->update_restored) + if ((mod = page->modify) == NULL || + !FLD_ISSET(mod->restore_state, WT_PAGE_RS_RESTORED)) return (true); /* @@ -1356,17 +1357,12 @@ __wt_page_evict_retry(WT_SESSION_IMPL *session, WT_PAGE *page) return (true); #ifdef HAVE_TIMESTAMPS - { - bool same_timestamp; - - same_timestamp = false; - if (!__wt_timestamp_iszero(&mod->last_eviction_timestamp)) - WT_WITH_TIMESTAMP_READLOCK(session, &txn_global->rwlock, - same_timestamp = __wt_timestamp_cmp( + if (!__wt_timestamp_iszero(&mod->last_eviction_timestamp)) { + __wt_txn_pinned_timestamp(session, &pinned_ts); + if (__wt_timestamp_cmp( &mod->last_eviction_timestamp, - &txn_global->pinned_timestamp) == 0); - if (!same_timestamp) - return (true); + &txn_global->pinned_timestamp) != 0) + return (true); } #endif @@ -1605,6 +1601,8 @@ __wt_split_descent_race( * update. A thread can read the parent page's original page index and * then read the split page's replacement index. * + * For example, imagine a search descending the tree. + * * Because internal page splits work by truncating the original page to * the initial part of the original page, the result of this race is we * will have a search key that points past the end of the current page. @@ -1649,73 +1647,17 @@ __wt_split_descent_race( * work by truncating the split page, so the split page search is for * content the split page retains after the split, and we ignore this * race. - */ - WT_INTL_INDEX_GET(session, ref->home, pindex); - return (pindex != saved_pindex); -} - -/* - * __wt_split_prev_race -- - * Return if we raced with an internal page split when moving backwards - * through the tree. - */ -static inline bool -__wt_split_prev_race(WT_SESSION_IMPL *session, WT_REF *ref) -{ - WT_PAGE_INDEX *pindex; - - /* - * There's a split race when a cursor moving backwards through the tree - * descends the tree. If we're splitting an internal page into its - * parent, we move the WT_REF structures and update the parent's page - * index before updating the split page's page index, and it's not an - * atomic update. A thread can read the parent and split page's original - * indexes during a split, or read the parent page's replacement page - * index and then read the split page's original index, either of which - * can lead to skipping pages. * - * For example, imagine an internal page with 3 child pages, with the - * namespaces a-f, g-h and i-j; the first child page splits. The parent - * starts out with the following page-index: + * This code is a general purpose check for a descent race and we call + * it in other cases, for example, a cursor traversing backwards through + * the tree. * - * | ... | a | g | i | ... | - * - * The split page starts out with the following page-index: - * - * | a | b | c | d | e | f | - * - * The first step is to move the c-f ranges into a new subtree, so, for - * example we might have two new internal pages 'c' and 'e', where the - * new 'c' page references the c-d namespace and the new 'e' page - * references the e-f namespace. The top of the subtree references the - * parent page, but until the parent's page index is updated, threads in - * the subtree won't be able to ascend out of the subtree. However, once - * the parent page's page index is updated to this: - * - * | ... | a | c | e | g | i | ... | - * - * threads in the subtree can ascend into the parent. Imagine a cursor - * in the c-d part of the namespace that ascends to the parent's 'c' - * slot. It would then decrement to the slot before the 'c' slot, the - * 'a' slot. - * - * The previous-cursor movement selects the last slot in the 'a' page; - * if the split page's page-index hasn't been updated yet, it selects - * the 'f' slot, which is incorrect. Once the split page's page index is - * updated to this: - * - * | a | b | - * - * the previous-cursor movement will select the 'b' slot, which is - * correct. - * - * This function takes an argument which is the internal page into which - * we're coupling. If the last slot on the page no longer points to - * the current page as its "home", the page is being split and part of - * its namespace moved, we have to restart. + * Presumably we acquired a page index on the child page before calling + * this code, don't re-order that acquisition with this check. */ - WT_INTL_INDEX_GET(session, ref->page, pindex); - return (pindex->index[pindex->entries - 1]->home != ref->page); + WT_BARRIER(); + WT_INTL_INDEX_GET(session, ref->home, pindex); + return (pindex != saved_pindex); } /* @@ -1724,8 +1666,8 @@ __wt_split_prev_race(WT_SESSION_IMPL *session, WT_REF *ref) * coupling up/down the tree. */ static inline int -__wt_page_swap_func(WT_SESSION_IMPL *session, - WT_REF *held, WT_REF *want, bool prev_race, uint32_t flags +__wt_page_swap_func( + WT_SESSION_IMPL *session, WT_REF *held, WT_REF *want, uint32_t flags #ifdef HAVE_DIAGNOSTIC , const char *file, int line #endif @@ -1755,18 +1697,6 @@ __wt_page_swap_func(WT_SESSION_IMPL *session, ); /* - * We can race when descending into an internal page as part of moving - * backwards through the tree, and we have to detect that race before - * releasing the page from which we are coupling, else we can't restart - * the movement. - */ - if (ret == 0 && prev_race && WT_PAGE_IS_INTERNAL(want->page) && - __wt_split_prev_race(session, want)) { - ret = WT_RESTART; - WT_TRET(__wt_page_release(session, want, flags)); - } - - /* * Expected failures: page not found or restart. Our callers list the * errors they're expecting to handle. */ |