1 files changed, 49 insertions, 85 deletions

diff --git a/src/third_party/wiredtiger/src/btree/bt_curprev.c b/src/third_party/wiredtiger/src/btree/bt_curprev.c
index 0099d1ae594..f8db9cd6233 100644
--- a/src/third_party/wiredtiger/src/btree/bt_curprev.c
+++ b/src/third_party/wiredtiger/src/btree/bt_curprev.c
@@ -40,7 +40,7 @@ __cursor_skip_prev(WT_CURSOR_BTREE *cbt)
     uint64_t recno;
     int i;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
 
 restart:
     /*
@@ -123,9 +123,8 @@ static inline int
 __cursor_fix_append_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
 {
     WT_SESSION_IMPL *session;
-    WT_UPDATE *upd;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
 
     /* If restarting after a prepare conflict, jump to the right spot. */
     if (restart)
@@ -198,28 +197,14 @@ __cursor_fix_append_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
         cbt->iface.value.data = &cbt->v;
     } else {
 restart_read:
-        WT_RET(__wt_txn_read_upd_list(session, cbt->ins->upd, &upd));
-        if (upd == NULL) {
+        WT_RET(__wt_txn_read_upd_list(session, cbt, cbt->ins->upd));
+        if (cbt->upd_value->type == WT_UPDATE_INVALID) {
             cbt->v = 0;
             cbt->iface.value.data = &cbt->v;
-        } else {
-            /*
-             * If this update has been restored from the disk, it needs to be freed after copying it
-             * to the user cursor.
-             */
-            if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK)) {
-                switch (upd->type) {
-                case WT_UPDATE_TOMBSTONE:
-                    cbt->iface.value.data = upd->data;
-                    __wt_free_update_list(session, &upd);
-                    break;
-                default:
-                    return (__wt_value_return(cbt, upd));
-                }
-            }
-            if (upd != NULL)
-                cbt->iface.value.data = upd->data;
-        }
+        } else if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE)
+            cbt->iface.value.data = cbt->upd_value->buf.data;
+        else
+            WT_RET(__wt_value_return(cbt, cbt->upd_value));
     }
     cbt->iface.value.size = 1;
     return (0);
@@ -235,9 +220,8 @@ __cursor_fix_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
     WT_BTREE *btree;
     WT_PAGE *page;
     WT_SESSION_IMPL *session;
-    WT_UPDATE *upd;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
     page = cbt->ref->page;
     btree = S2BT(session);
 
@@ -265,35 +249,21 @@ new_page:
     cbt->ins = __col_insert_search(cbt->ins_head, cbt->ins_stack, cbt->next_stack, cbt->recno);
     if (cbt->ins != NULL && cbt->recno != WT_INSERT_RECNO(cbt->ins))
         cbt->ins = NULL;
-    upd = NULL;
     /*
-     * FIXME-PM-1523: Now we only do transaction read if we have an update chain and it doesn't work
+     * FIXME-WT-6127: Now we only do transaction read if we have an update chain and it doesn't work
      * in durable history. Review this when we have a plan for fixed-length column store.
      */
+    __wt_upd_value_clear(cbt->upd_value);
     if (cbt->ins != NULL)
 restart_read:
-    WT_RET(__wt_txn_read(session, cbt, NULL, cbt->recno, cbt->ins->upd, NULL, &upd));
-    if (upd == NULL) {
+    WT_RET(__wt_txn_read(session, cbt, NULL, cbt->recno, cbt->ins->upd, NULL));
+    if (cbt->upd_value->type == WT_UPDATE_INVALID) {
         cbt->v = __bit_getv_recno(cbt->ref, cbt->recno, btree->bitcnt);
         cbt->iface.value.data = &cbt->v;
-    } else {
-        /*
-         * If this update has been restored from the disk, it needs to be freed after copying it to
-         * the user cursor.
-         */
-        if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK)) {
-            switch (upd->type) {
-            case WT_UPDATE_TOMBSTONE:
-                cbt->iface.value.data = upd->data;
-                __wt_free_update_list(session, &upd);
-                break;
-            default:
-                return (__wt_value_return(cbt, upd));
-            }
-        }
-        if (upd != NULL)
-            cbt->iface.value.data = upd->data;
-    }
+    } else if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE)
+        cbt->iface.value.data = cbt->upd_value->buf.data;
+    else
+        WT_RET(__wt_value_return(cbt, cbt->upd_value));
     cbt->iface.value.size = 1;
     return (0);
 }
@@ -306,9 +276,8 @@ static inline int
 __cursor_var_append_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
 {
     WT_SESSION_IMPL *session;
-    WT_UPDATE *upd;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
 
     /* If restarting after a prepare conflict, jump to the right spot. */
     if (restart)
@@ -327,17 +296,16 @@ new_page:
 
         __cursor_set_recno(cbt, WT_INSERT_RECNO(cbt->ins));
 restart_read:
-        WT_RET(__wt_txn_read_upd_list(session, cbt->ins->upd, &upd));
-        if (upd == NULL)
+        WT_RET(__wt_txn_read_upd_list(session, cbt, cbt->ins->upd));
+        if (cbt->upd_value->type == WT_UPDATE_INVALID)
             continue;
-        if (upd->type == WT_UPDATE_TOMBSTONE) {
-            if (upd->txnid != WT_TXN_NONE && __wt_txn_upd_visible_all(session, upd))
+        if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE) {
+            if (cbt->upd_value->txnid != WT_TXN_NONE &&
+              __wt_txn_upd_value_visible_all(session, cbt->upd_value))
                 ++cbt->page_deleted_count;
-            if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK) && upd->type != WT_UPDATE_TOMBSTONE)
-                __wt_free_update_list(session, &upd);
             continue;
         }
-        return (__wt_value_return(cbt, upd));
+        return (__wt_value_return(cbt, cbt->upd_value));
     }
     /* NOTREACHED */
 }
@@ -355,10 +323,9 @@ __cursor_var_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
     WT_INSERT *ins;
     WT_PAGE *page;
     WT_SESSION_IMPL *session;
-    WT_UPDATE *upd;
     uint64_t rle_start;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
     page = cbt->ref->page;
 
     rle_start = 0; /* -Werror=maybe-uninitialized */
@@ -398,18 +365,17 @@ restart_read:
         /* Check any insert list for a matching record. */
         cbt->ins_head = WT_COL_UPDATE_SLOT(page, cbt->slot);
         cbt->ins = __col_insert_search_match(cbt->ins_head, cbt->recno);
-        upd = NULL;
+        __wt_upd_value_clear(cbt->upd_value);
         if (cbt->ins != NULL)
-            WT_RET(__wt_txn_read_upd_list(session, cbt->ins->upd, &upd));
-        if (upd != NULL) {
-            if (upd->type == WT_UPDATE_TOMBSTONE) {
-                if (upd->txnid != WT_TXN_NONE && __wt_txn_upd_visible_all(session, upd))
+            WT_RET(__wt_txn_read_upd_list(session, cbt, cbt->ins->upd));
+        if (cbt->upd_value->type != WT_UPDATE_INVALID) {
+            if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE) {
+                if (cbt->upd_value->txnid != WT_TXN_NONE &&
+                  __wt_txn_upd_value_visible_all(session, cbt->upd_value))
                     ++cbt->page_deleted_count;
-                if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK))
-                    __wt_free_update_list(session, &upd);
                 continue;
             }
-            return (__wt_value_return(cbt, upd));
+            return (__wt_value_return(cbt, cbt->upd_value));
         }
 
         /*
@@ -449,8 +415,9 @@ restart_read:
                 continue;
             }
 
-            WT_RET(__wt_bt_col_var_cursor_walk_txn_read(session, cbt, page, &unpack, cip, &upd));
-            if (upd == NULL)
+            WT_RET(__wt_bt_col_var_cursor_walk_txn_read(session, cbt, page, &unpack, cip));
+            if (cbt->upd_value->type == WT_UPDATE_INVALID ||
+              cbt->upd_value->type == WT_UPDATE_TOMBSTONE)
                 continue;
             return (0);
         }
@@ -474,10 +441,9 @@ __cursor_row_prev(WT_CURSOR_BTREE *cbt, bool newpage, bool restart)
     WT_PAGE *page;
     WT_ROW *rip;
     WT_SESSION_IMPL *session;
-    WT_UPDATE *upd;
     bool kpack_used;
 
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
     page = cbt->ref->page;
     key = &cbt->iface.key;
 
@@ -536,17 +502,16 @@ restart_read_insert:
         if ((ins = cbt->ins) != NULL) {
             key->data = WT_INSERT_KEY(ins);
             key->size = WT_INSERT_KEY_SIZE(ins);
-            WT_RET(__wt_txn_read_upd_list(session, ins->upd, &upd));
-            if (upd == NULL)
+            WT_RET(__wt_txn_read_upd_list(session, cbt, ins->upd));
+            if (cbt->upd_value->type == WT_UPDATE_INVALID)
                 continue;
-            if (upd->type == WT_UPDATE_TOMBSTONE) {
-                if (upd->txnid != WT_TXN_NONE && __wt_txn_upd_visible_all(session, upd))
+            if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE) {
+                if (cbt->upd_value->txnid != WT_TXN_NONE &&
+                  __wt_txn_upd_value_visible_all(session, cbt->upd_value))
                     ++cbt->page_deleted_count;
-                if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK))
-                    __wt_free_update_list(session, &upd);
                 continue;
             }
-            return (__wt_value_return(cbt, upd));
+            return (__wt_value_return(cbt, cbt->upd_value));
         }
 
         /* Check for the beginning of the page. */
@@ -574,17 +539,16 @@ restart_read_page:
         rip = &page->pg_row[cbt->slot];
         WT_RET(__cursor_row_slot_key_return(cbt, rip, &kpack, &kpack_used));
         WT_RET(__wt_txn_read(
-          session, cbt, &cbt->iface.key, WT_RECNO_OOB, WT_ROW_UPDATE(page, rip), NULL, &upd));
-        if (upd == NULL)
+          session, cbt, &cbt->iface.key, WT_RECNO_OOB, WT_ROW_UPDATE(page, rip), NULL));
+        if (cbt->upd_value->type == WT_UPDATE_INVALID)
             continue;
-        if (upd->type == WT_UPDATE_TOMBSTONE) {
-            if (upd->txnid != WT_TXN_NONE && __wt_txn_upd_visible_all(session, upd))
+        if (cbt->upd_value->type == WT_UPDATE_TOMBSTONE) {
+            if (cbt->upd_value->txnid != WT_TXN_NONE &&
+              __wt_txn_upd_value_visible_all(session, cbt->upd_value))
                 ++cbt->page_deleted_count;
-            if (F_ISSET(upd, WT_UPDATE_RESTORED_FROM_DISK))
-                __wt_free_update_list(session, &upd);
             continue;
         }
-        return (__wt_value_return(cbt, upd));
+        return (__wt_value_return(cbt, cbt->upd_value));
     }
     /* NOTREACHED */
 }
@@ -604,7 +568,7 @@ __wt_btcur_prev(WT_CURSOR_BTREE *cbt, bool truncating)
     bool newpage, restart;
 
     cursor = &cbt->iface;
-    session = (WT_SESSION_IMPL *)cbt->iface.session;
+    session = CUR2S(cbt);
 
     WT_STAT_CONN_INCR(session, cursor_prev);
     WT_STAT_DATA_INCR(session, cursor_prev);