diff options
Diffstat (limited to 'storage/innobase/row/row0merge.cc')
| -rw-r--r-- | storage/innobase/row/row0merge.cc | 37 |
1 files changed, 31 insertions, 6 deletions
diff --git a/storage/innobase/row/row0merge.cc b/storage/innobase/row/row0merge.cc index 3c9331d9909..33990f619c6 100644 --- a/storage/innobase/row/row0merge.cc +++ b/storage/innobase/row/row0merge.cc @@ -1,7 +1,7 @@ /***************************************************************************** Copyright (c) 2005, 2017, Oracle and/or its affiliates. All Rights Reserved. -Copyright (c) 2014, 2020, MariaDB Corporation. +Copyright (c) 2014, 2021, MariaDB Corporation. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software @@ -1739,7 +1739,7 @@ row_merge_read_clustered_index( ut_malloc_nokey(n_index * sizeof *merge_buf)); row_merge_dup_t clust_dup = {index[0], table, col_map, 0}; - dfield_t* prev_fields; + dfield_t* prev_fields = nullptr; const ulint n_uniq = dict_index_get_n_unique(index[0]); ut_ad(trx->mysql_thd != NULL); @@ -1838,6 +1838,34 @@ row_merge_read_clustered_index( btr_pcur_move_to_prev_on_page(&pcur); } + uint64_t n_rows = 0; + + /* Check if the table is supposed to be empty for our read view. + + If we read bulk_trx_id as an older transaction ID, it is not + incorrect to check here whether that transaction should be + visible to us. If bulk_trx_id is not visible to us, the table + must have been empty at an earlier point of time, also in our + read view. + + An INSERT would only update bulk_trx_id in + row_ins_clust_index_entry_low() if the table really was empty + (everything had been purged), when holding a leaf page latch + in the clustered index (actually, the root page is the only + leaf page in that case). + + We are holding a clustered index leaf page latch here. + That will obviously prevent any concurrent INSERT from + updating bulk_trx_id while we read it. */ + if (!online) { + } else if (trx_id_t bulk_trx_id = old_table->bulk_trx_id) { + ut_ad(trx->read_view.is_open()); + ut_ad(bulk_trx_id != trx->id); + if (!trx->read_view.changes_visible(bulk_trx_id)) { + goto func_exit; + } + } + if (old_table != new_table) { /* The table is being rebuilt. Identify the columns that were flagged NOT NULL in the new table, so that @@ -1884,13 +1912,10 @@ row_merge_read_clustered_index( prev_fields = static_cast<dfield_t*>( ut_malloc_nokey(n_uniq * sizeof *prev_fields)); mtuple_heap = mem_heap_create(sizeof(mrec_buf_t)); - } else { - prev_fields = NULL; } mach_write_to_8(new_sys_trx_start, trx->id); mach_write_to_8(new_sys_trx_end, TRX_ID_MAX); - uint64_t n_rows = 0; /* Scan the clustered index. */ for (;;) { @@ -2720,7 +2745,7 @@ all_done: UT_DELETE(clust_btr_bulk); } - if (prev_fields != NULL) { + if (prev_fields) { ut_free(prev_fields); mem_heap_free(mtuple_heap); } |