[Tarantool-patches] [PATCH 13/16] tx: introduce txm_story
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Wed Jul 15 02:46:24 MSK 2020
Thanks for the patch!
See 3 comments below.
On 08.07.2020 17:14, Aleksandr Lyapunov wrote:
> ---
> src/box/txn.c | 725 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
> src/box/txn.h | 127 ++++++++++
> 2 files changed, 851 insertions(+), 1 deletion(-)
>
> diff --git a/src/box/txn.c b/src/box/txn.c
> index b9f1737..78c542f 100644
> --- a/src/box/txn.c
> +++ b/src/box/txn.c
> @@ -1095,4 +1141,681 @@ txm_cause_conflict(struct txn *wreaker, struct txn *victim)
> rlist_add(&wreaker->conflict_list, &tracker->in_conflict_list);
> rlist_add(&wreaker->conflicted_by_list, &tracker->in_conflicted_by_list);
> return 0;
> -}
> \ No newline at end of file
> +}
> +
> +struct txm_story *
> +txm_story_new(struct tuple *tuple, uint32_t index_count)
> +{
> + assert(!tuple->is_dirty);
> + assert(index_count < BOX_INDEX_MAX);
> + struct mempool *pool = &txm.txm_story_pool[index_count];
> + struct txm_story *story = (struct txm_story *)mempool_alloc(pool);
> + if (story == NULL) {
> + size_t item_size = sizeof(struct txm_story) +
> + index_count * sizeof(struct txm_story_link);
> + diag_set(OutOfMemory, item_size,
> + "tx_manager", "tx story");
> + return story;
1. What if index count of the space will change in a concurrect
DDL transaction?
> + }
> + story->tuple = tuple;
> +
> + const struct txm_story **put_story = (const struct txm_story **)&story;
> + struct txm_story **empty = NULL;
> + mh_int_t pos = mh_history_put(txm.history, put_story, &empty, 0);
> + if (pos == mh_end(txm.history)) {
> + mempool_free(pool, story);
> + diag_set(OutOfMemory, pos + 1,
> + "tx_manager", "tx history hash table");
> + return NULL;
> + }
> + tuple->is_dirty = true;
> + tuple_ref(tuple);
> +
> + story->index_count = index_count;
> + story->add_stmt = NULL;
> + story->add_psn = 0;
> + story->del_stmt = NULL;
> + story->del_psn = 0;
> + rlist_create(&story->reader_list);
> + rlist_add(&txm.all_stories, &story->in_all_stories);
> + memset(story->link, 0, sizeof(story->link[0]) * index_count);
> + return story;
> +}
> +
> +static struct txm_story *
> +txm_story_new_add_stmt(struct tuple *tuple, struct txn_stmt *stmt)
2. Probably would be better to use the existing terms: old_tuple and new_tuple.
So the functions would be txm_story_add_new_stmt and txm_story_add_old_stmt. The
same in all the other places. 'add_stmt' -> 'new_stmt'. 'del_stmt' -> 'old_stmt'.
> +{
> + struct txm_story *res = txm_story_new(tuple, stmt->space->index_count);
> + if (res == NULL)
> + return NULL;
> + res->add_stmt = stmt;
> + assert(stmt->add_story == NULL);
> + stmt->add_story = res;
> + return res;
> +}
> +
> +static struct txm_story *
> +txm_story_new_del_stmt(struct tuple *tuple, struct txn_stmt *stmt)
> +{
> + struct txm_story *res = txm_story_new(tuple, stmt->space->index_count);
> + if (res == NULL)
> + return NULL;
> + res->del_stmt = stmt;
> + assert(stmt->del_story == NULL);
> + stmt->del_story = res;
> + return res;
> +}
> +
> +void
> +txm_history_prepare_stmt(struct txn_stmt *stmt)
> +{
> + assert(stmt->txn->psn != 0);
> +
> + /* Move story to the past to prepared stories. */
> +
> + struct txm_story *story = stmt->add_story;
> + uint32_t index_count = story == NULL ? 0 : story->index_count;
> + for (uint32_t i = 0; i < index_count; ) {
> + if (!story->link[i].older.is_story) {
> + /* tuple is old. */
> + i++;
> + continue;
> + }
> + struct txm_story *old_story =
> + story->link[i].older.story;
> + if (old_story->del_psn != 0) {
> + /* is psn is set, the change is prepared. */
> + i++;
> + continue;
> + }
> + if (old_story->add_psn != 0) {
> + /* is psn is set, the change is prepared. */
> + i++;
> + continue;
> + }
> +
> + if (old_story->add_stmt != NULL) {
> + /* ancient */
> + i++;
> + continue;
> + }
> + if (old_story->add_stmt->txn == stmt->txn) {
> + /* added by us. */
> + i++;
> + continue;
> + }
> +
> + if (old_story->add_stmt->preserve_old_tuple || i != 0)
> + old_story->add_stmt->txn->status = TXN_CONFLICTED;
> +
> + /* Swap story and old story. */
> + struct txm_story_link *link = &story->link[i];
> + if (link->newer_story == NULL) {
> + /* we have to replace the tuple in index. */
> + struct tuple *unused;
> + struct index *index = stmt->space->index[i];
> + if (index_replace(index, story->tuple,
> + old_story->tuple,
> + DUP_INSERT, &unused) != 0) {
> + diag_log();
> + unreachable();
> + panic("failed to rollback change");
> + }
> + } else {
> + struct txm_story *newer = link->newer_story;
> + assert(newer->link[i].older.is_story);
> + assert(newer->link[i].older.story == story);
> + txm_story_unlink(newer, i);
> + txm_story_link_story(newer, old_story, i);
> + }
> +
> + txm_story_unlink(story, i);
> +
> + txm_story_unlink(story, i);
> + if (old_story->link[i].older.is_story) {
> + struct txm_story *to =
> + old_story->link[i].older.story;
> + txm_story_unlink(old_story, i);
> + txm_story_link_story(story, to, i);
> + } else {
> + struct tuple *to =
> + old_story->link[i].older.tuple;
> + txm_story_unlink(old_story, i);
> + txm_story_link_tuple(story, to, i);
> + }
> +
> + txm_story_link_story(old_story, story, i);
> +
> + if (i == 0) {
> + assert(stmt->del_story == old_story);
> + assert(story->link[0].older.is_story ||
> + story->link[0].older.tuple == NULL);
> +
> + struct txn_stmt *dels = old_story->del_stmt;
> + assert(dels != NULL);
> + do {
> + if (dels->txn != stmt->txn)
> + dels->txn->status = TXN_CONFLICTED;
> + dels->del_story = NULL;
> + struct txn_stmt *next = dels->next_in_del_list;
> + dels->next_in_del_list = NULL;
> + dels = next;
> + } while (dels != NULL);
> + old_story->del_stmt = NULL;
> +
> + if (story->link[0].older.is_story) {
> + struct txm_story *oldest_story =
> + story->link[0].older.story;
> + dels = oldest_story->del_stmt;
> + while (dels != NULL) {
> + assert(dels->txn != stmt->txn);
> + dels->del_story = NULL;
> + struct txn_stmt *next =
> + dels->next_in_del_list;
> + dels->next_in_del_list = NULL;
> + dels = next;
> + }
> + oldest_story->del_stmt = stmt;
> + stmt->del_story = oldest_story;
> + }
> + }
> + }
> + if (stmt->add_story != NULL)
3. According to a check in the beginning of the function stmt can
be NULL. But then this will crash.
> + stmt->add_story->add_psn = stmt->txn->psn;
> +
> + if (stmt->del_story != NULL)
> + stmt->del_story->del_psn = stmt->txn->psn;
> +}
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