[Tarantool-patches] [PATCH v3 08/13] txm: introduce tx manager

[Aleksandr Lyapunov]

Define TX manager. It will store data for MVCC and conflict manager.
Define also 'use_mvcc_engine' in config that enables MVCC engine.

Part of #4897
---
 src/box/lua/load_cfg.lua        |  2 ++
 src/box/txn.c                   | 21 +++++++++++++++++++++
 src/box/txn.h                   | 12 ++++++++++++
 src/main.cc                     |  5 +++++
 test/app-tap/init_script.result |  1 +
 test/box/admin.result           |  2 ++
 test/box/cfg.result             |  4 ++++
 7 files changed, 47 insertions(+)

diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
index 107bc15..8b40b29 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -82,6 +82,7 @@ local default_cfg = {
     coredump            = false,
     read_only           = false,
     hot_standby         = false,
+    use_mvcc_engine     = false,
     checkpoint_interval = 3600,
     checkpoint_wal_threshold = 1e18,
     checkpoint_count    = 2,
@@ -162,6 +163,7 @@ local template_cfg = {
     checkpoint_count    = 'number',
     read_only           = 'boolean',
     hot_standby         = 'boolean',
+    use_mvcc_engine     = 'boolean',
     worker_pool_threads = 'number',
     replication_timeout = 'number',
     replication_sync_lag = 'number',
diff --git a/src/box/txn.c b/src/box/txn.c
index d254edb..d647fc9 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -38,6 +38,16 @@
 #include "errinj.h"
 #include "iproto_constants.h"
 
+struct tx_manager
+{
+};
+
+/** That's a definition, see declaration for description. */
+bool tx_manager_use_mvcc_engine = false;
+
+/** The one and only instance of tx_manager. */
+static struct tx_manager txm;
+
 double too_long_threshold;
 
 /* Txn cache. */
@@ -1165,3 +1175,14 @@ txn_on_yield(struct trigger *trigger, void *event)
 	txn_set_flag(txn, TXN_IS_ABORTED_BY_YIELD);
 	return 0;
 }
+
+void
+tx_manager_init()
+{
+	(void)txm;
+}
+
+void
+tx_manager_free()
+{
+}
diff --git a/src/box/txn.h b/src/box/txn.h
index 962ada0..a2374f3 100644
--- a/src/box/txn.h
+++ b/src/box/txn.h
@@ -43,6 +43,12 @@ extern "C" {
 
 /** box statistics */
 extern struct rmean *rmean_box;
+/**
+ * Global flag that enables mvcc engine.
+ * If set, memtx starts to apply statements through txm history mechanism
+ * and tx manager itself transaction reads in order to detect conflicts.
+ */
+extern bool tx_manager_use_mvcc_engine;
 
 struct journal_entry;
 struct engine;
@@ -700,6 +706,12 @@ box_txn_savepoint(void);
 API_EXPORT int
 box_txn_rollback_to_savepoint(box_txn_savepoint_t *savepoint);
 
+void
+tx_manager_init();
+
+void
+tx_manager_free();
+
 #if defined(__cplusplus)
 } /* extern "C" */
 #endif /* defined(__cplusplus) */
diff --git a/src/main.cc b/src/main.cc
index 65b1606..07eafb8 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -75,6 +75,7 @@
 #include <libutil.h>
 #include "box/lua/init.h" /* box_lua_init() */
 #include "box/session.h"
+#include "box/txn.h"
 #include "systemd.h"
 #include "crypto/crypto.h"
 #include "core/popen.h"
@@ -569,6 +570,8 @@ load_cfg(void)
 			log_format,
 			background);
 
+	tx_manager_use_mvcc_engine = cfg_getb("use_mvcc_engine");
+
 	if (background)
 		daemonize();
 
@@ -667,6 +670,7 @@ tarantool_free(void)
 	random_free();
 #endif
 	crypto_free();
+	tx_manager_free();
 	coll_free();
 	systemd_free();
 	say_logger_free();
@@ -830,6 +834,7 @@ main(int argc, char **argv)
 	signal_init();
 	cbus_init();
 	coll_init();
+	tx_manager_init();
 	crypto_init();
 	systemd_init();
 	tarantool_lua_init(tarantool_bin, main_argc, main_argv);
diff --git a/test/app-tap/init_script.result b/test/app-tap/init_script.result
index 857f0c9..3838e35 100644
--- a/test/app-tap/init_script.result
+++ b/test/app-tap/init_script.result
@@ -37,6 +37,7 @@ slab_alloc_factor:1.05
 sql_cache_size:5242880
 strip_core:true
 too_long_threshold:0.5
+use_mvcc_engine:false
 vinyl_bloom_fpr:0.05
 vinyl_cache:134217728
 vinyl_dir:.
diff --git a/test/box/admin.result b/test/box/admin.result
index ab3e80a..278e8c5 100644
--- a/test/box/admin.result
+++ b/test/box/admin.result
@@ -95,6 +95,8 @@ cfg_filter(box.cfg)
     - true
   - - too_long_threshold
     - 0.5
+  - - use_mvcc_engine
+    - false
   - - vinyl_bloom_fpr
     - 0.05
   - - vinyl_cache
diff --git a/test/box/cfg.result b/test/box/cfg.result
index bdd210b..b5ba165 100644
--- a/test/box/cfg.result
+++ b/test/box/cfg.result
@@ -83,6 +83,8 @@ cfg_filter(box.cfg)
  |     - true
  |   - - too_long_threshold
  |     - 0.5
+ |   - - use_mvcc_engine
+ |     - false
  |   - - vinyl_bloom_fpr
  |     - 0.05
  |   - - vinyl_cache
@@ -190,6 +192,8 @@ cfg_filter(box.cfg)
  |     - true
  |   - - too_long_threshold
  |     - 0.5
+ |   - - use_mvcc_engine
+ |     - false
  |   - - vinyl_bloom_fpr
  |     - 0.05
  |   - - vinyl_cache
-- 
2.7.4