[Tarantool-patches] [PATCH 12/15] tx: introduce txm_story
Aleksandr Lyapunov
alyapunov at tarantool.org
Fri Jul 3 09:33:14 MSK 2020
---
src/box/txn.c | 516 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
src/box/txn.h | 129 +++++++++++++++
2 files changed, 644 insertions(+), 1 deletion(-)
diff --git a/src/box/txn.c b/src/box/txn.c
index 79384f0..26377c6 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -35,13 +35,44 @@
#include <fiber.h>
#include "xrow.h"
#include "errinj.h"
+#include "small/mempool.h"
+
+static uint32_t
+txm_story_key_hash(const struct tuple *a)
+{
+ uintptr_t u = (uintptr_t)a;
+ if (sizeof(uintptr_t) <= sizeof(uint32_t))
+ return u;
+ else
+ return u ^ (u >> 32);
+}
+
+#define mh_name _history
+#define mh_key_t struct tuple *
+#define mh_node_t struct txm_story *
+#define mh_arg_t int
+#define mh_hash(a, arg) (txm_story_key_hash((*(a))->tuple))
+#define mh_hash_key(a, arg) (txm_story_key_hash(a))
+#define mh_cmp(a, b, arg) ((*(a))->tuple != (*(b))->tuple)
+#define mh_cmp_key(a, b, arg) ((a) != (*(b))->tuple)
+#define MH_SOURCE
+#include "salad/mhash.h"
struct tx_manager
{
/** Last prepare-sequence-number that was assigned to preped TX. */
int64_t last_psn;
+ /** Mempools for tx_story objects with difference index count. */
+ struct mempool txm_story_pool[BOX_INDEX_MAX];
+ /** Hash table tuple -> txm_story of that tuple. */
+ struct mh_history_t *history;
+ /** List of all txm_story objects. */
+ struct rlist all_stories;
+ /** Iterator that sequentially traverses all txm_story objects. */
+ struct rlist *traverse_all_stories;
};
+/** The one and only instance of tx_manager. */
static struct tx_manager txm;
struct tx_conflict_tracker {
@@ -119,6 +150,9 @@ txn_stmt_new(struct region *region)
stmt->space = NULL;
stmt->old_tuple = NULL;
stmt->new_tuple = NULL;
+ stmt->add_story = NULL;
+ stmt->del_story = NULL;
+ stmt->next_in_del_list = NULL;
stmt->engine_savepoint = NULL;
stmt->row = NULL;
stmt->has_triggers = false;
@@ -1022,11 +1056,23 @@ txn_on_yield(struct trigger *trigger, void *event)
void
tx_manager_init()
{
+ for (size_t i = 0; i < BOX_INDEX_MAX; i++) {
+ size_t item_size = sizeof(struct txm_story) +
+ i * sizeof(struct txm_story_link);
+ mempool_create(&txm.txm_story_pool[i],
+ cord_slab_cache(), item_size);
+ }
+ txm.history = mh_history_new();
+ rlist_create(&txm.all_stories);
+ txm.traverse_all_stories = &txm.all_stories;
}
void
tx_manager_free()
{
+ mh_history_delete(txm.history);
+ for (size_t i = 0; i < BOX_INDEX_MAX; i++)
+ mempool_destroy(&txm.txm_story_pool[i]);
}
int
@@ -1070,4 +1116,472 @@ 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, struct txn_stmt *stmt, 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;
+ }
+ 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 = stmt;
+ 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;
+}
+
+/** Temporary allocated on region that stores a conflicting TX. */
+struct txn_conflict
+{
+ struct txn *wreaker;
+ struct txn_conflict *next;
+};
+
+int
+txm_check_and_link_add_story(struct txm_story *story, struct txn_stmt *stmt,
+ enum dup_replace_mode mode)
+{
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ assert(!story->link[i].is_old_story);
+ struct tuple *next_tuple = story->link[i].old_tuple;
+ if (next_tuple != NULL && next_tuple->is_dirty) {
+ struct txm_story *next = txm_story_get(next_tuple);
+ assert(next->link[i].new_story == NULL);
+ story->link[i].is_old_story = true;
+ story->link[i].old_story = next;
+ next->link[i].new_story = story;
+ }
+ }
+
+ struct region *region = &stmt->txn->region;
+ size_t region_svp = region_used(region);
+ struct txn_conflict *collected_conflicts = NULL;
+
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ struct tuple *visible = NULL;
+ struct txm_story *node = story;
+ while (true) {
+ if (!node->link[i].is_old_story) {
+ /*
+ * the tuple is so old that we doesn't
+ * know its story.
+ */
+ visible = node->link[i].old_tuple;
+ assert(visible == NULL || !visible->is_dirty);
+ break;
+ }
+ node = node->link[i].old_story;
+
+ if (node->del_psn != 0) {
+ /* deleted by at least prepared TX. */
+ break;
+ }
+ if (node->del_stmt != NULL &&
+ node->del_stmt->txn == stmt->txn)
+ break; /* deleted by us. */
+ if (node->add_psn != 0) {
+ /* added by at least prepared TX. */
+ visible = node->tuple;
+ break;
+ }
+ if (node->add_stmt == NULL) {
+ /*
+ * the tuple is so old that we lost
+ * the beginning of its story.
+ */
+ visible = node->tuple;
+ break;
+ }
+ if (node->add_stmt->txn == stmt->txn) {
+ /* added by us. */
+ visible = node->tuple;
+ break;
+ }
+ /*
+ * We skip the story but once the story is committed
+ * before out TX that may cause conflict.
+ * The conflict will be inavoidable if this statement
+ * relies on old_tuple. If not (it's a replace),
+ * the conflict will take place only for secondary
+ * index if the story will not be overwritten in primary
+ * index.
+ */
+ bool cross_conflict = false;
+ if (stmt->preserve_old_tuple) {
+ cross_conflict = true;
+ } else if (i != 0) {
+ struct txm_story *look_up = node;
+ cross_conflict = true;
+ while (look_up->link[0].new_story != NULL) {
+ struct txm_story *over;
+ over = look_up->link[0].new_story;
+ if (over->add_stmt->txn == stmt->txn) {
+ cross_conflict = false;
+ break;
+ }
+ look_up = over;
+ }
+ }
+ if (!cross_conflict)
+ continue;
+ size_t err_size;
+ struct txn_conflict *next_conflict;
+ next_conflict =
+ region_alloc_object(region,
+ struct txn_conflict,
+ &err_size);
+ if (next_conflict == NULL) {
+ diag_set(OutOfMemory, err_size,
+ "txn_region", "txn conflict");
+ goto fail;
+ }
+ next_conflict->wreaker = node->add_stmt->txn;
+ next_conflict->next = collected_conflicts;
+ collected_conflicts = next_conflict;
+ }
+
+ int errcode;
+ errcode = replace_check_dup(stmt->old_tuple, visible,
+ i == 0 ? mode : DUP_INSERT);
+ if (errcode != 0) {
+ struct space *sp = stmt->space;
+ if (sp != NULL)
+ diag_set(ClientError, errcode,
+ sp->index[i]->def->name,
+ space_name(sp));
+ goto fail;
+ }
+ }
+
+ if (story->link[0].is_old_story) {
+ stmt->next_in_del_list = story->link[0].old_story->del_stmt;
+ story->link[0].old_story->del_stmt = stmt;
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ if (story->link[i].is_old_story)
+ continue;
+ if (story->link[i].old_tuple != NULL)
+ tuple_ref(story->link[i].old_tuple);
+ }
+ } else if (story->link[0].old_tuple != NULL) {
+ struct tuple *old_tuple = story->link[0].old_tuple;
+ struct txm_story *del_story;
+ del_story = txm_story_new(old_tuple, NULL, story->index_count);
+ if (del_story == NULL)
+ goto fail;
+ del_story->del_stmt = stmt;
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ if (story->link[i].is_old_story)
+ continue;
+ if (story->link[i].old_tuple == old_tuple) {
+ story->link[i].is_old_story = true;
+ story->link[i].old_story = del_story;
+ } else if (story->link[i].old_tuple != NULL) {
+ tuple_ref(story->link[i].old_tuple);
+ }
+ }
+ }
+
+ while (collected_conflicts != NULL) {
+ if (txm_cause_conflict(collected_conflicts->wreaker,
+ stmt->txn) != 0) {
+ goto fail;
+ }
+ collected_conflicts = collected_conflicts->next;
+ }
+ stmt->add_story = story;
+
+ region_truncate(region, region_svp);
+ return 0;
+
+fail:
+ for (uint32_t j = story->index_count; j > 0; j--) {
+ uint32_t i = j - 1;
+ if (story->link[i].is_old_story) {
+ struct txm_story *next = story->link[i].old_story;
+ story->link[i].is_old_story = false;
+ story->link[i].old_tuple = next->tuple;
+ next->link[i].new_story = NULL;
+ }
+ }
+ region_truncate(region, region_svp);
+ return -1;
+}
+
+int
+txm_link_del_story(struct tuple *old_tuple, struct txn_stmt *stmt,
+ uint32_t index_count)
+{
+ if (old_tuple->is_dirty) {
+ struct txm_story *story = txm_story_get(old_tuple);
+ stmt->next_in_del_list = story->del_stmt;
+ story->del_stmt = stmt;
+ stmt->del_story = story;
+ return 0;
+ }
+ struct txm_story *del_story;
+ del_story = txm_story_new(old_tuple, NULL, index_count);
+ if (del_story == NULL)
+ return -1;
+ del_story->del_stmt = stmt;
+ stmt->del_story = del_story;
+ return 0;
+}
+
+void
+txm_unlink_add_story(struct txn_stmt *stmt)
+{
+ assert(stmt->add_story != NULL);
+
+ struct txm_story *story = stmt->add_story;
+
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ struct txm_story_link *from = &story->link[i];
+ if (from->new_story == NULL) {
+ struct tuple *unused;
+ struct index *index = stmt->space->index[i];
+ struct tuple *rollback = from->is_old_story ?
+ from->old_story->tuple :
+ from->old_tuple;
+ if (index_replace(index, story->tuple, rollback,
+ DUP_INSERT, &unused) != 0) {
+ diag_log();
+ unreachable();
+ panic("failed to rollback change");
+ }
+ if (i == 0 && rollback != NULL)
+ tuple_ref(rollback);
+ } else {
+ struct txm_story *new_story = from->new_story;
+ struct txm_story_link *to = &new_story->link[i];
+ assert(to->is_old_story);
+ assert(to->old_story == story);
+ to->is_old_story = from->is_old_story;
+ if (from->is_old_story) {
+ to->old_story = from->old_story;
+ from->old_story = NULL;
+ } else {
+ to->old_tuple = from->old_tuple;
+ from->old_tuple = NULL;
+ }
+ from->is_old_story = false;
+ }
+ }
+
+ stmt->add_story = NULL;
+}
+
+void
+txm_unlink_del_story(struct txn_stmt *stmt)
+{
+ assert(stmt->del_story != NULL);
+
+ struct txm_story *story = stmt->del_story;
+
+ struct txn_stmt **prev = &story->del_stmt;
+ while (*prev != stmt) {
+ prev = &(*prev)->next_in_del_list;
+ assert(*prev != NULL);
+ }
+ *prev = stmt->next_in_del_list;
+
+ stmt->del_story = NULL;
+}
+
+void
+txm_prepare_add_story(struct txn_stmt *stmt)
+{
+ assert(stmt->txn->psn != 0);
+ assert(stmt->add_story != NULL);
+ struct txm_story *story = stmt->add_story;
+
+ /* Move story to the past to prepared stories. */
+
+ while (true) {
+ if (!story->link[0].is_old_story)
+ break; /* tuple is prepared. */
+ struct txm_story *old_story = story->link[0].old_story;
+ if (old_story->del_psn != 0)
+ break; /* is psn is set, the change is prepared. */
+ if (old_story->add_psn != 0)
+ break; /* is psn is set, the change is prepared. */
+ if (old_story->add_stmt != NULL)
+ break; /* ancient */
+ if (old_story->add_stmt->txn == stmt->txn)
+ break; /* added by us. */
+
+ /* Swap story and old story. */
+ for (uint32_t i = 0; i < old_story->index_count; i++) {
+ if (!story->link[i].is_old_story ||
+ story->link[i].old_story != old_story)
+ continue;
+ if (story->link[i].new_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 {
+ assert(story->link[i].new_story->link[i].old_story == story);
+ story->link[i].new_story->link[i].old_story = old_story;
+ }
+ old_story->link[i].new_story = story->link[i].new_story;
+
+ story->link[i].is_old_story = old_story->link[i].is_old_story;
+ if (old_story->link[i].is_old_story) {
+ story->link[i].old_story = old_story->link[i].old_story;
+ assert(old_story->link[i].old_story->link[i].new_story == old_story);
+ old_story->link[i].old_story->link[i].new_story = story;
+ } else {
+ story->link[i].old_tuple = old_story->link[i].old_tuple;
+ }
+ old_story->link[i].is_old_story = true;
+ old_story->link[i].old_story = story;
+ }
+ }
+ story->add_psn = stmt->txn->psn;
+}
+
+void
+txm_let_it_go(struct txn_stmt *stmt)
+{
+ if (stmt->add_story != NULL) {
+ stmt->add_story->add_stmt = NULL;
+ stmt->add_story = NULL;
+ }
+ if (stmt->del_story != NULL) {
+ struct txn_stmt **dels = &stmt->del_story->del_stmt;
+ while ((*dels) != stmt) {
+ assert(*dels != NULL);
+ dels = &(*dels)->next_in_del_list;
+ }
+ *dels = (*dels)->next_in_del_list;
+ stmt->del_story = NULL;
+ }
+}
+
+struct txm_story *
+txm_story_get(struct tuple *tuple)
+{
+ assert(tuple->is_dirty);
+
+ mh_int_t pos = mh_history_find(txm.history, tuple, 0);
+ assert(pos != mh_end(txm.history));
+ return *mh_history_node(txm.history, pos);
+}
+
+struct tuple *
+txm_tuple_clarify_slow(struct txn* txn, struct tuple* tuple, uint32_t index,
+ uint32_t mk_index, bool prepared_ok)
+{
+ struct tuple *result = NULL;
+ struct mh_history_t *hist = txm.history;
+ mh_int_t pos = mh_history_find(hist, tuple, 0);
+ assert(pos != mh_end(hist));
+ struct txm_story *story = *mh_history_node(hist, pos);
+ bool own_change = false;
+
+ while (true) {
+ struct txn_stmt *dels = story->del_stmt;
+ while (dels != NULL) {
+ if (dels->txn == txn) {
+ /* deleted by us. */
+ own_change = true;
+ break;
+ }
+ dels = dels->next_in_del_list;
+ }
+ if (prepared_ok && story->del_psn != 0) {
+ /* deleted by prepared. */
+ break;
+ }
+ if (story->del_psn != 0 && story->del_stmt == NULL) {
+ /* deleted by committed. */
+ break;
+ }
+
+ if (story->add_stmt != NULL && story->add_stmt->txn == txn) {
+ /* added by us. */
+ result = story->tuple;
+ break;
+ }
+
+ if (prepared_ok && story->add_psn != 0) {
+ /* added by prepared. */
+ result = story->tuple;
+ break;
+ }
+
+ if (story->add_psn != 0 && story->add_stmt == NULL) {
+ /* added by committed. */
+ result = story->tuple;
+ break;
+ }
+
+ if (!story->link[index].is_old_story) {
+ return story->link[index].old_tuple;
+ }
+
+ story = story->link[index].old_story;
+ }
+ (void)own_change; /* TODO: add conflict */
+ (void)mk_index; /* TODO: multiindex */
+ return result;
+}
+void
+txm_story_delete(struct txm_story *story)
+{
+ if (txm.traverse_all_stories == &story->in_all_stories)
+ txm.traverse_all_stories = rlist_next(txm.traverse_all_stories);
+ rlist_del(&story->in_all_stories);
+ tuple_unref(story->tuple);
+ story->tuple->is_dirty = false;
+
+ for (uint32_t i = 0; i < story->index_count; i++) {
+ if (!story->link[i].is_old_story &&
+ story->link[i].old_tuple != NULL) {
+ tuple_unref(story->link[i].old_tuple);
+ }
+ }
+
+#ifndef NDEBUG
+ const char poison_char = '?';
+ size_t item_size = sizeof(struct txm_story) +
+ story->index_count * sizeof(struct txm_story_link);
+ memset(story, poison_char, item_size);
+#endif
+
+ struct mempool *pool = &txm.txm_story_pool[story->index_count];
+ mempool_free(pool, story);
+}
diff --git a/src/box/txn.h b/src/box/txn.h
index 92c0116..b5eda1e 100644
--- a/src/box/txn.h
+++ b/src/box/txn.h
@@ -36,6 +36,7 @@
#include "trigger.h"
#include "fiber.h"
#include "space.h"
+#include "tuple.h"
#if defined(__cplusplus)
extern "C" {
@@ -123,6 +124,18 @@ struct txn_stmt {
struct space *space;
struct tuple *old_tuple;
struct tuple *new_tuple;
+ /**
+ * If new_tuple != NULL and this transaction was not prepared,
+ * this member holds added story of the new_tuple.
+ */
+ struct txm_story *add_story;
+ /**
+ * If new_tuple == NULL and this transaction was not prepared,
+ * this member holds added story of the old_tuple.
+ */
+ struct txm_story *del_story;
+ /** Link in txm_story::del_stmt linked list. */
+ struct txn_stmt *next_in_del_list;
/** Engine savepoint for the start of this statement. */
void *engine_savepoint;
/** Redo info: the binary log row */
@@ -284,6 +297,80 @@ struct txn {
struct rlist conflicted_by_list;
};
+/**
+ * Link that connects a txm_story with older and newer stories of the same
+ * key in index.
+ */
+struct txm_story_link {
+ /** Story that was happened after that story was ended. */
+ struct txm_story *new_story;
+ /** Flag whether there is older story of the same key in index. */
+ bool is_old_story;
+ union {
+ /** is_old_story = true. Older story of the same key. */
+ struct txm_story *old_story;
+ /**
+ * is_old_story = false. Tuple that was in the index before
+ * this story. That tuple is either NULL or so old that
+ * we don't have a story about it.
+ */
+
+ struct tuple *old_tuple;
+ };
+};
+
+/**
+ * A part of a history of a value in space.
+ * It's a story about a tuple, from the point it was added to space to the
+ * point when it was deleted from a space.
+ * All stories are linked into a list of stories of the same key of each index.
+ */
+struct txm_story {
+ /** The story is about thist tuple. */
+ struct tuple *tuple;
+ /**
+ * Statement that told this story. Is set to NULL when the statement's
+ * transaction becomes committed. Can also be NULL if we don't know who
+ * introduced that story.
+ */
+ struct txn_stmt *add_stmt;
+ /**
+ * Prepare sequence number of add_stmt's transaction. Is set when
+ * the transactions is prepared. Can be 0 if the transaction is
+ * in progress or we don't know who introduced that story.
+ */
+ int64_t add_psn;
+ /**
+ * Statement that ended this story. Is set to NULL when the statement's
+ * transaction becomes committed. Can also be NULL if the tuple has not
+ * been deleted yet.
+ */
+ struct txn_stmt *del_stmt;
+ /**
+ * Prepare sequence number of del_stmt's transaction. Is set when
+ * the transactions is prepared. Can be 0 if the transaction is
+ * in progress or if nobody has deleted the tuple.
+ */
+ int64_t del_psn;
+ /**
+ * List of trackers - transactions that has read this tuple.
+ */
+ struct rlist reader_list;
+ /**
+ * Link in tx_manager::all_stories
+ */
+ struct rlist in_all_stories;
+ /**
+ * Number of indexes in this space - and the count of link[].
+ */
+ uint32_t index_count;
+ /**
+ * Link with older and newer stories (and just tuples) for each
+ * index respectively.
+ */
+ struct txm_story_link link[];
+};
+
static inline bool
txn_has_flag(struct txn *txn, enum txn_flag flag)
{
@@ -652,6 +739,48 @@ tx_manager_free();
int
txm_cause_conflict(struct txn *wreaker, struct txn *victim);
+struct txm_story *
+txm_story_new(struct tuple *tuple, struct txn_stmt *stmt, uint32_t index_count);
+
+int
+txm_check_and_link_add_story(struct txm_story *story, struct txn_stmt *stmt,
+ enum dup_replace_mode mode);
+
+int
+txm_link_del_story(struct tuple *old_tuple, struct txn_stmt *stmt,
+ uint32_t index_count);
+
+void
+txm_unlink_add_story(struct txn_stmt *stmt);
+
+void
+txm_unlink_del_story(struct txn_stmt *stmt);
+
+void
+txm_prepare_add_story(struct txn_stmt *stmt);
+
+void
+txm_let_it_go(struct txn_stmt *stmt);
+
+struct txm_story *
+txm_story_get(struct tuple *tuple);
+
+struct tuple *
+txm_tuple_clarify_slow(struct txn *txn, struct tuple *tuple, uint32_t index,
+ uint32_t mk_index, bool prepared_ok);
+
+static inline struct tuple*
+txm_tuple_clarify(struct txn *txn, struct tuple* tuple, uint32_t index,
+ uint32_t mk_index, bool prepared_ok)
+{
+ if (!tuple->is_dirty)
+ return tuple;
+ return txm_tuple_clarify_slow(txn, tuple, index, mk_index, prepared_ok);
+}
+
+void
+txm_story_delete(struct txm_story *story);
+
#if defined(__cplusplus)
} /* extern "C" */
#endif /* defined(__cplusplus) */
--
2.7.4
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