From b7065d33f547038881c36c49b03ea4a9d8a7caec Mon Sep 17 00:00:00 2001
From: Aleksandr Lyapunov <alyapunov@tarantool.org>
Date: Thu, 12 Aug 2021 10:36:35 +0300
Subject: [PATCH] txm: track read instead of direct conflict in clarify
After the previous patch it became possible to link read trackers
to in-progress stories.
This patch use one read tracker instead of bunch of direct
conflicts in tuple_clarify. This is a bit accurate. Is also allows
to avoid unnecessary conflict when a transaction reads its own
change.
Part of #5999
---
src/box/memtx_tx.c | 12 ++----
test/box/tx_man.result | 81 ++++++++++++++++++++++++++++++++++++++++
test/box/tx_man.test.lua | 25 +++++++++++++
3 files changed, 110 insertions(+), 8 deletions(-)
diff --git a/src/box/memtx_tx.c b/src/box/memtx_tx.c
index 08a13b7658..60f910855d 100644
--- a/src/box/memtx_tx.c
+++ b/src/box/memtx_tx.c
@@ -1856,6 +1856,7 @@ memtx_tx_tuple_clarify_slow(struct txn *txn, struct space *space,
{
assert(tuple->is_dirty);
struct memtx_story *story = memtx_tx_story_get(tuple);
+ struct memtx_story *last_checked_story = story;
bool own_change = false;
struct tuple *result = NULL;
@@ -1864,17 +1865,12 @@ memtx_tx_tuple_clarify_slow(struct txn *txn, struct space *space,
is_prepared_ok, &own_change)) {
break;
}
- /*
- * If somebody have added a tuple that we don't see, then
- * when he commits we must go to read view or conflicted.
- */
- if (story->add_stmt != NULL && txn != NULL)
- memtx_tx_cause_conflict(story->add_stmt->txn, txn);
story = story->link[index->dense_id].older_story;
if (story == NULL)
break;
+ last_checked_story = story;
}
- if (!own_change && story != NULL) {
+ if (!own_change) {
/*
* If the result tuple exists (is visible) - it is visible in
* every index. But if we found a story of deleted tuple - we
@@ -1883,7 +1879,7 @@ memtx_tx_tuple_clarify_slow(struct txn *txn, struct space *space,
*/
int shift = index->dense_id & 63;
uint64_t mask = result == NULL ? 1ull << shift : UINT64_MAX;
- memtx_tx_track_read_story(txn, space, story, mask);
+ memtx_tx_track_read_story(txn, space, last_checked_story, mask);
}
if (mk_index != 0) {
assert(false); /* TODO: multiindex */
diff --git a/test/box/tx_man.result b/test/box/tx_man.result
index e3f81d8ce6..109c48bd56 100644
--- a/test/box/tx_man.result
+++ b/test/box/tx_man.result
@@ -3436,6 +3436,87 @@ s:drop()
| ---
| ...
+-- A pair of test that was created during #5999 investigation.
+s=box.schema.space.create("s", {engine="memtx"})
+ | ---
+ | ...
+ti=s:create_index("ti", {type="tree"})
+ | ---
+ | ...
+tx1:begin()
+ | ---
+ | -
+ | ...
+tx2:begin()
+ | ---
+ | -
+ | ...
+tx1('s:replace{1, 1}')
+ | ---
+ | - - [1, 1]
+ | ...
+tx2('s:replace{1, 2}')
+ | ---
+ | - - [1, 2]
+ | ...
+rc1 = tx1('s:select{1}')
+ | ---
+ | ...
+rc2 = tx2('s:select{1}')
+ | ---
+ | ...
+tx1:commit() -- Must not fail
+ | ---
+ | -
+ | ...
+tx2:commit() -- Must not fail
+ | ---
+ | -
+ | ...
+s:drop()
+ | ---
+ | ...
+
+s=box.schema.space.create("s", {engine="memtx"})
+ | ---
+ | ...
+ti=s:create_index("ti", {type="tree"})
+ | ---
+ | ...
+tx1:begin()
+ | ---
+ | -
+ | ...
+tx2:begin()
+ | ---
+ | -
+ | ...
+tx1('s:replace{1, 1}')
+ | ---
+ | - - [1, 1]
+ | ...
+tx2('s:replace{1, 2}')
+ | ---
+ | - - [1, 2]
+ | ...
+rc1 = tx1('s:select{1}')
+ | ---
+ | ...
+rc2 = tx2('s:select{1}')
+ | ---
+ | ...
+tx2:commit() -- Must not fail
+ | ---
+ | -
+ | ...
+tx1:commit() -- Must not fail
+ | ---
+ | -
+ | ...
+s:drop()
+ | ---
+ | ...
+
test_run:cmd("switch default")
| ---
| - true
diff --git a/test/box/tx_man.test.lua b/test/box/tx_man.test.lua
index 4ac4d8af30..972816f2d6 100644
--- a/test/box/tx_man.test.lua
+++ b/test/box/tx_man.test.lua
@@ -1105,6 +1105,31 @@ tx2:commit() -- MUST BE OK
s:drop()
+-- A pair of test that was created during #5999 investigation.
+s=box.schema.space.create("s", {engine="memtx"})
+ti=s:create_index("ti", {type="tree"})
+tx1:begin()
+tx2:begin()
+tx1('s:replace{1, 1}')
+tx2('s:replace{1, 2}')
+rc1 = tx1('s:select{1}')
+rc2 = tx2('s:select{1}')
+tx1:commit() -- Must not fail
+tx2:commit() -- Must not fail
+s:drop()
+
+s=box.schema.space.create("s", {engine="memtx"})
+ti=s:create_index("ti", {type="tree"})
+tx1:begin()
+tx2:begin()
+tx1('s:replace{1, 1}')
+tx2('s:replace{1, 2}')
+rc1 = tx1('s:select{1}')
+rc2 = tx2('s:select{1}')
+tx2:commit() -- Must not fail
+tx1:commit() -- Must not fail
+s:drop()
+
test_run:cmd("switch default")
test_run:cmd("stop server tx_man")
test_run:cmd("cleanup server tx_man")
--
GitLab