[Tarantool-patches] [PATCH v1] test: fix hang of vinyl/select_consistency.* test

["Alexander V. Tikhonov" <avtikhon@tarantool.org>]

During testing process:

  https://gitlab.com/tarantool/tarantool/-/jobs/800863457#L5303

found that test vinyl/select_consistency.test.lua hanged:

  --- vinyl/select_consistency.result		Thu Jun 11 11:59:48 2020
  +++ var/152_vinyl/select_consistency.result	Tue Oct 20 09:13:02 2020
  @@ -137,16 +137,3 @@
   for i = 1, ch:size() do
       ch:get()
   end;
  ----
  -...
  -test_run:cmd("setopt delimiter ''");
  ----
  -- true
  -...

This issue stops the testing till the complete timeout of the test-run
will stop all the testing process.

Also found that real hang occured at box.snapshot command in snap_loop
loop, like:

  [001] Last 15 lines of Tarantool Log file [Instance "vinyl"][/source/test/var/001_vinyl/vinyl.log]:
  [001] 2020-11-15 18:13:49.928 [78887] main/105/gc I> removed /source/test/var/001_vinyl/vinyl/519/2/00000000000000011145.run
  [001] 2020-11-15 18:13:49.928 [78887] vinyl.dump.0/640/task I> writing `/source/test/var/001_vinyl/vinyl/519/0/00000000000000011538.index'
  [001] 2020-11-15 18:13:49.928 [78887] snapshot/101/main I> done
  [001] 2020-11-15 18:13:49.929 [78887] main/105/gc I> removed /source/test/var/001_vinyl/vinyl/519/2/00000000000000011157.index
  [001] 2020-11-15 18:13:49.929 [78887] main/108/vinyl.scheduler I> 519/0: dump completed
  [001] 2020-11-15 18:13:49.929 [78887] main/108/vinyl.scheduler I> dumped 0 bytes in 0.0 s, rate 0.0 MB/s
  [001] 2020-11-15 18:13:49.929 [78887] main/481/lua I> vinyl checkpoint completed
  [001] 2020-11-15 18:13:49.929 [78887] main/105/gc I> removed /source/test/var/001_vinyl/vinyl/519/2/00000000000000011157.run
  [001] 2020-11-15 18:13:49.929 [78887] main/108/vinyl.scheduler I> 519/0: started compacting range ([94]..inf), runs 2/2
  [001] 2020-11-15 18:13:49.930 [78887] wal I> removed /source/test/var/001_vinyl/vinyl/00000000000000093070.xlog
  [001] 2020-11-15 18:13:49.930 [78887] main/105/gc I> removed /source/test/var/001_vinyl/vinyl/00000000000000094030.snap.inprogress
  [001] 2020-11-15 18:13:49.930 [78887] main I> removed /source/test/var/001_vinyl/vinyl/00000000000000093306.snap
  [001] 2020-11-15 18:13:49.930 [78887] main I> removed /source/test/var/001_vinyl/vinyl/00000000000000093070.vylog
  [001] 2020-11-15 18:13:49.931 [78887] main/481/lua F> can't rename .snap.inprogress
  [001] 2020-11-15 18:13:49.931 [78887] main/481/lua F> can't rename .snap.inprogress

It happened because on heavy loaded hosts may occure the situation
when the previous snapshot was inprogress when the new snapshot came
with the same file name *.snap.inprogress. It happens before the
current snapshot completed and printed "dump completed" in log file.
Also this file *.snap.inprogress was seen left on manual debug, when
the test hanged before this patch. To resolve the test issue fiber
sleep delay after it can be increased, but we want to save the issue
reproducable. The current patch corrects the test to avoid of hang on
box snapshot, to be able to continue testing after it failed. Fiber
sleep was even decreased after adding fiber for box.snapshot to be
able to reproduce the issue.

Needed for #4385
---

Github: https://github.com/tarantool/tarantool/tree/avtikhon/gh-4385_hang_select_consistency
Issue: https://github.com/tarantool/tarantool/issues/4385

 test/vinyl/select_consistency.result   | 51 +++++++++++++++++++-------
 test/vinyl/select_consistency.test.lua | 45 ++++++++++++++++-------
 test/vinyl/suite.ini                   |  3 +-
 3 files changed, 71 insertions(+), 28 deletions(-)

diff --git a/test/vinyl/select_consistency.result b/test/vinyl/select_consistency.result
index f27d0ec68..cd99b84bf 100644
--- a/test/vinyl/select_consistency.result
+++ b/test/vinyl/select_consistency.result
@@ -4,6 +4,9 @@ test_run = require('test_run').new()
 fiber = require 'fiber'
 ---
 ...
+log = require 'log'
+---
+...
 math.randomseed(os.time())
 ---
 ...
@@ -52,6 +55,8 @@ function gen_update()
 end;
 ---
 ...
+failed = false
+
 function dml_loop()
     local insert = true
     while not stop do
@@ -75,8 +80,13 @@ end;
 ...
 function snap_loop()
     while not stop do
-        box.snapshot()
-        fiber.sleep(0.1)
+        local ok, err = fiber.create(function() local ok, err = pcall(box.snapshot) return ok, err end)
+        if ok == false then
+            log.info("error: box.snapshot failed with error " .. err)
+            failed = true
+            break
+        end
+        fiber.sleep(0.01)
     end
     ch:put(true)
 end;
@@ -97,10 +107,7 @@ _ = fiber.create(dml_loop);
 _ = fiber.create(snap_loop);
 ---
 ...
-failed = {};
----
-...
-for i = 1, 10000 do
+function run_iter()
     local val = math.random(MAX_VAL)
     box.begin()
     local res1 = s.index.i1:select({val})
@@ -117,25 +124,37 @@ for i = 1, 10000 do
                 end
             end
             if not found then
+                log.error("error: equal not found for #res1 = " .. #res1 .. ", #res2 = " .. #res2)
                 equal = false
                 break
             end
         end
-    else
-        equal = false
-    end
-    if not equal then
-        table.insert(failed, {res1, res2})
     end
     fiber.sleep(0)
+    return equal
+end;
+---
+...
+for i = 1, 10000 do
+    if failed or not run_iter(i) then
+        log.error("error: failed on iteration " .. i)
+        failed = true
+        break
+    end
 end;
 ---
 ...
 stop = true;
 ---
 ...
-for i = 1, ch:size() do
-    ch:get()
+function check_get()
+    for i = 1, ch:size() do
+        if not test_run:wait_cond(function() return ch:get() ~= nil end) then
+            log.error("error: hanged on ch:get() on iteration " .. i)
+            return false
+	end
+    end
+    return true
 end;
 ---
 ...
@@ -143,10 +162,14 @@ test_run:cmd("setopt delimiter ''");
 ---
 - true
 ...
-#failed == 0 or failed
+test_run:wait_cond(function() return check_get() end)
 ---
 - true
 ...
+failed
+---
+- false
+...
 s:drop()
 ---
 ...
diff --git a/test/vinyl/select_consistency.test.lua b/test/vinyl/select_consistency.test.lua
index 73b443e89..e5e01b741 100644
--- a/test/vinyl/select_consistency.test.lua
+++ b/test/vinyl/select_consistency.test.lua
@@ -1,6 +1,7 @@
 test_run = require('test_run').new()
 
 fiber = require 'fiber'
+log = require 'log'
 
 math.randomseed(os.time())
 
@@ -33,6 +34,8 @@ function gen_update()
     pcall(s.update, s, math.random(MAX_KEY), {{'+', 5, 1}})
 end;
 
+failed = false
+
 function dml_loop()
     local insert = true
     while not stop do
@@ -55,8 +58,13 @@ end;
 
 function snap_loop()
     while not stop do
-        box.snapshot()
-        fiber.sleep(0.1)
+        local ok, err = fiber.create(function() local ok, err = pcall(box.snapshot) return ok, err end)
+        if ok == false then
+            log.info("error: box.snapshot failed with error " .. err)
+            failed = true
+            break
+        end
+        fiber.sleep(0.01)
     end
     ch:put(true)
 end;
@@ -68,9 +76,7 @@ _ = fiber.create(dml_loop);
 _ = fiber.create(dml_loop);
 _ = fiber.create(snap_loop);
 
-failed = {};
-
-for i = 1, 10000 do
+function run_iter()
     local val = math.random(MAX_VAL)
     box.begin()
     local res1 = s.index.i1:select({val})
@@ -87,26 +93,39 @@ for i = 1, 10000 do
                 end
             end
             if not found then
+                log.error("error: equal not found for #res1 = " .. #res1 .. ", #res2 = " .. #res2)
                 equal = false
                 break
             end
         end
-    else
-        equal = false
-    end
-    if not equal then
-        table.insert(failed, {res1, res2})
     end
     fiber.sleep(0)
+    return equal
+end;
+
+for i = 1, 10000 do
+    if failed or not run_iter(i) then
+        log.error("error: failed on iteration " .. i)
+        failed = true
+        break
+    end
 end;
 
 stop = true;
-for i = 1, ch:size() do
-    ch:get()
+
+function check_get()
+    for i = 1, ch:size() do
+        if not test_run:wait_cond(function() return ch:get() ~= nil end) then
+            log.error("error: hanged on ch:get() on iteration " .. i)
+            return false
+	end
+    end
+    return true
 end;
 
 test_run:cmd("setopt delimiter ''");
 
-#failed == 0 or failed
+test_run:wait_cond(function() return check_get() end)
+failed
 
 s:drop()
diff --git a/test/vinyl/suite.ini b/test/vinyl/suite.ini
index 1fded2393..d55e7734c 100644
--- a/test/vinyl/suite.ini
+++ b/test/vinyl/suite.ini
@@ -23,7 +23,8 @@ fragile = {
             "issues": [ "gh-4346" ]
         },
         "select_consistency.test.lua": {
-            "issues": [ "gh-4385" ]
+            "issues": [ "gh-4385" ],
+            "checksums": [ "817493231b4ce2ebb8aa295303e857df" ]
         },
         "throttle.test.lua": {
             "issues": [ "gh-4168" ]
-- 
2.25.1