diff --git a/src/box/lua/info.c b/src/box/lua/info.c
index 44d28a1725ee6ea6bfc87ea32194d42b672e015b..e46b8b87e3fe55d0d181ded8bbe2504ed511238c 100644
--- a/src/box/lua/info.c
+++ b/src/box/lua/info.c
@@ -731,6 +731,15 @@ lbox_info_synchro(struct lua_State *L)
lua_setfield(L, -2, "busy");
luaL_pushuint64(L, queue->promote_greatest_term);
lua_setfield(L, -2, "term");
+ if (queue->len == 0) {
+ lua_pushnumber(L, 0);
+ } else {
+ struct txn_limbo_entry *oldest_entry =
+ txn_limbo_first_entry(queue);
+ double now = fiber_clock();
+ lua_pushnumber(L, now - oldest_entry->insertion_time);
+ }
+ lua_setfield(L, -2, "age");
lua_setfield(L, -2, "queue");
return 1;
diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index 00618bb94424dbef7b34077cc452634c0ba041a0..f182bf4e83b8f7813c72dc17782548d4114e810e 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -170,6 +170,7 @@ txn_limbo_append(struct txn_limbo *limbo, uint32_t id, struct txn *txn)
e->ack_count = 0;
e->is_commit = false;
e->is_rollback = false;
+ e->insertion_time = fiber_clock();
rlist_add_tail_entry(&limbo->queue, e, in_queue);
limbo->len++;
return e;
diff --git a/src/box/txn_limbo.h b/src/box/txn_limbo.h
index ce93c9d10c100476addf324a474d81ae07423085..307e8b7a38ad5a07e07a2d060be12c5470575691 100644
--- a/src/box/txn_limbo.h
+++ b/src/box/txn_limbo.h
@@ -69,6 +69,8 @@ struct txn_limbo_entry {
*/
bool is_commit;
bool is_rollback;
+ /** When this entry was added to the queue. */
+ double insertion_time;
};
static inline bool
diff --git a/test/replication-luatest/gh_9918_synchro_queue_additional_info_test.lua b/test/replication-luatest/gh_9918_synchro_queue_additional_info_test.lua
new file mode 100644
index 0000000000000000000000000000000000000000..5bc73cd8ae04f7094761282104971db3432bb905
--- /dev/null
+++ b/test/replication-luatest/gh_9918_synchro_queue_additional_info_test.lua
@@ -0,0 +1,112 @@
+local fiber = require('fiber')
+local t = require('luatest')
+local replica_set = require('luatest.replica_set')
+local server = require('luatest.server')
+
+local g = t.group()
+
+g.before_each(function(cg)
+ cg.replica_set = replica_set:new{}
+ local box_cfg = {
+ replication = {
+ server.build_listen_uri('server1', cg.replica_set.id),
+ server.build_listen_uri('server2', cg.replica_set.id),
+ },
+ replication_timeout = 0.1,
+ replication_synchro_timeout = 60,
+ }
+ cg.leader = cg.replica_set:build_and_add_server{
+ alias = 'server1',
+ box_cfg = box_cfg,
+ }
+ cg.replica = cg.replica_set:build_and_add_server{
+ alias = 'server2',
+ box_cfg = box_cfg,
+ }
+ cg.replica_set:start()
+ cg.leader:exec(function()
+ box.ctl.promote()
+ local s = box.schema.space.create('s', {is_sync = true})
+ s:create_index('pk')
+ end)
+ cg.replica_set:wait_for_fullmesh()
+ cg.leader:wait_for_downstream_to(cg.replica)
+end)
+
+g.after_each(function(cg)
+ cg.replica_set:drop()
+end)
+
+-- Test that new `age` field of `box.info.synchro.queue` works correctly.
+g.test_age_field = function(cg)
+ -- The synchronous queue is originally empty.
+ cg.leader:exec(function()
+ t.assert_equals(box.info.synchro.queue.age, 0)
+ end)
+ cg.replica:exec(function()
+ t.assert_equals(box.info.synchro.queue.age, 0)
+ end)
+
+ -- Ensure that the synchronous transactions stay in the queue for a while.
+ cg.leader:update_box_cfg{replication_synchro_quorum = 3}
+ -- Add the first entry to the synchronous queue.
+ local fid1 = cg.leader:exec(function()
+ local fiber = require('fiber')
+
+ local f = fiber.new(function() box.space.s:replace{0} end)
+ f:set_joinable(true)
+ return f:id()
+ end)
+ local wait_time = 0.1
+ fiber.sleep(wait_time)
+
+ local leader_age = cg.leader:exec(function(wait_time)
+ t.assert_ge(box.info.synchro.queue.age, wait_time)
+ t.assert_le(box.info.synchro.queue.age,
+ box.cfg.replication_synchro_timeout)
+ return box.info.synchro.queue.age
+ end, {wait_time})
+ local replica_age = cg.replica:exec(function()
+ t.assert_ge(box.info.synchro.queue.age, 0)
+ t.assert_le(box.info.synchro.queue.age,
+ box.cfg.replication_synchro_timeout)
+ return box.info.synchro.queue.age
+ end)
+
+ -- Add another entry to the synchronous queue.
+ local fid2 = cg.leader:exec(function()
+ local f = require('fiber').new(function() box.space.s:replace{0} end)
+ f:set_joinable(true)
+ return f:id()
+ end)
+ fiber.sleep(wait_time)
+
+ -- The age of the oldest synchronous queue entry must be shown.
+ cg.leader:exec(function(age)
+ t.assert_ge(box.info.synchro.queue.age, age)
+ t.assert_le(box.info.synchro.queue.age,
+ box.cfg.replication_synchro_timeout)
+ end, {leader_age})
+ cg.replica:exec(function(age)
+ t.assert_ge(box.info.synchro.queue.age, age)
+ t.assert_le(box.info.synchro.queue.age,
+ box.cfg.replication_synchro_timeout)
+ end, {replica_age})
+
+ -- Allow the synchronous queue to advance.
+ cg.leader:update_box_cfg{replication_synchro_quorum = ''}
+ cg.leader:exec(function(fids)
+ for _, fid in ipairs(fids) do
+ t.assert(require('fiber').find(fid):join())
+ end
+ end, {{fid1, fid2}})
+ cg.leader:wait_for_downstream_to(cg.replica)
+
+ -- The synchronous queue must become empty by this time.
+ cg.leader:exec(function()
+ t.assert_equals(box.info.synchro.queue.age, 0)
+ end)
+ cg.replica:exec(function()
+ t.assert_equals(box.info.synchro.queue.age, 0)
+ end)
+end