[Tarantool-patches] [PATCH v6] memtx: fix out of memory handling for rtree

[Sergey Ostanevich]

Olga,

Thanks for explanation! LGTM.

Sergos

On 03 мар 14:50, Olga Arkhangelskaia wrote:
> Hi Sergey! I need time to check everything!
> 
> I can not use error injection that exists in memtx_index_extent_reserve(),
> 
> because it is used  in memtx_space_replace_all_keys ant it is called prior
> memtx_rtree_index_reserve() .
> 
> If we use memtx_index_extent_reserve(), injection we will not reach the
> place where error with rtree occures.
> 
> So to make sure that we fixed the problem we need
> memtx_rtree_index_reserve() to fail.
> 
> 
> 19.02.2020 19:28, Sergey Ostanevich пишет:
> > Hi!
> > 
> > I am sorry, I took the OKriw/gh-4619-RTREE-doesnt-handle-OOM-properly
> > branch for review, instead of OKriw/gh-RTREE-doesnt-handle-OOM-properly
> > 
> > I can see memtx_index_extent_reserve() has an error injection already.
> > Is it not sufficient, so you still need a new one in
> > memtx_rtree_index_reserve() ?
> 
> > Otherwise looks good.
> > 
> > Regards,
> > Sergos
> > 
> > 
> > On 18 фев 21:20, Olga Arkhangelskaia wrote:
> > > Hi! Thanks for the review! But I am a bit confused.
> > > 
> > > 18.02.2020 15:46, Sergey Ostanevich пишет:
> > > > Hi!
> > > > 
> > > > Thanks for the patch!
> > > > 
> > > > I wonder why do you use additional by-ref argument to pass an integer
> > > > result instead of redefining the interface into:
> > > > 
> > > >       int
> > > >       rtree_insert(struct rtree *tree, struct rtree_rect *rect, record_t obj)
> > > > 
> > > > instead, so that all uses of a form:
> > > > 
> > > >       int err = 0;
> > > >       ...
> > > >       rtree_insert(&index->tree, &rect, new_tuple, &err);
> > > 
> > > There is no way rtree returns an error. Library itself can not fail.  And
> > > the best way is to reserve pages before malloc itself in the library.
> > > 
> > > We have discussed in the very beginning with Konstantin Osipov and later
> > > with Aleksandr Lyapunov.
> > > 
> > > https://lists.tarantool.org/pipermail/tarantool-patches/2019-November/012392.html
> > > 
> > > So we reserve memory instead of returning an error.
> > > 
> > > >       if (err == 1) {
> > > >           diag_set(OutOfMemory, sizeof(struct rtree),
> > > >                   "rtree", "rtree_page");
> > > >           return -1;
> > > >       }
> > > > 
> > > > into a much simpler:
> > > > 
> > > >       if (rtree_insert(&index->tree, &rect, new_tuple, &err)) {
> > > >           diag_set(OutOfMemory, sizeof(struct rtree),
> > > >                   "rtree", "rtree_page");
> > > >           return -1;
> > > >       }
> > > > 
> > > > Sergos
> > > > 
> > > > On 11 Feb 15:42, Nikita Pettik wrote:
> > > > > On 11 Feb 13:51, Olga Arkhangelskaia wrote:
> > > > > > Hi Nikita! Thanks for the review.
> > > > > > 
> > > > > > I have fixed everything you have pointed out. Diff can be found below.
> > > > > LGTM
> > > > > > 10.02.2020 14:18, Nikita Pettik пишет:
> > > > > > > On 10 Feb 10:47, Olga Arkhangelskaia wrote:
> > > > > >    diff --git a/src/box/index.cc b/src/box/index.cc
> > > > > > -index 4e4867118..c2fc00867 100644
> > > > > > +index 4e4867118..750838bef 100644
> > > > > >    --- a/src/box/index.cc
> > > > > >    +++ b/src/box/index.cc
> > > > > > -@@ -733,6 +733,13 @@ int
> > > > > > +@@ -733,6 +733,8 @@ int
> > > > > >     generic_index_build_next(struct index *index, struct tuple *tuple)
> > > > > > {
> > > > > >           struct tuple *unused;
> > > > > > -+ /*
> > > > > > -+       * Note this is not no-op call in case of rtee index:
> > > > > > -+       * reserving 0 bytes is required during rtree recovery.
> > > > > > -+       * For details see memtx_rtree_index_reserve().
> > > > > > -+ */
> > > > > >    +      if (index_reserve(index, 0) != 0)
> > > > > >    +              return -1;
> > > > > > 
> > > > > > diff --git a/src/box/memtx_rtree.c b/src/box/memtx_rtree.c
> > > > > > -index 8badad797..612fcb2a9 100644
> > > > > > +index 8badad797..a5cae8f45 100644
> > > > > >    --- a/src/box/memtx_rtree.c
> > > > > >    +++ b/src/box/memtx_rtree.c
> > > > > > -@@ -242,6 +242,24 @@ memtx_rtree_index_replace(struct index *base, struct
> > > > > > tuple *old_tuple,
> > > > > > +@@ -242,6 +242,23 @@ memtx_rtree_index_replace(struct index *base, struct
> > > > > > tuple *old_tuple,
> > > > > >           return 0;
> > > > > > }
> > > > > > 
> > > > > > @@ -82,14 +109,13 @@
> > > > > >    +memtx_rtree_index_reserve(struct index *base, uint32_t size_hint)
> > > > > >    +{
> > > > > >    + /*
> > > > > > -+         * In case of rtree we use reserve to make sure that
> > > > > > -+         * memory allocation will not fail during any operation
> > > > > > -+         * on rtree, because there is no error handling in the
> > > > > > -+         * rtree lib.
> > > > > > -+ */
> > > > > > ++       * In case of rtree we use reserve to make sure that memory
> > > > > > allocation
> > > > > > ++       * will not fail durig any operationin rtree, because there is no
> > > > > > ++       * error handling in rtree lib.
> > > > > > ++ */
> > > > > >    + (void)size_hint;
> > > > > >    +      ERROR_INJECT(ERRINJ_INDEX_RESERVE, {
> > > > > > -+              diag_set(OutOfMemory, MEMTX_EXTENT_SIZE, "mempool", "new
> > > > > > slab");
> > > > > > ++              diag_set(OutOfMemory, MEMTX_EXTENT_SIZE, "slab allocator",
> > > > > > "memtx extent");
> > > > > >    +              return -1;
> > > > > >    + });
> > > > > >    +      struct memtx_engine *memtx = (struct memtx_engine *)base->engine;
> > > > > > 
> > > > > >    diff --git a/test/box/errinj.test.lua b/test/box/errinj.test.lua
> > > > > > -index 03c088677..63c8b19fe 100644
> > > > > > +index 03c088677..598e7da33 100644
> > > > > >    --- a/test/box/errinj.test.lua
> > > > > >    +++ b/test/box/errinj.test.lua
> > > > > > -@@ -620,3 +620,31 @@ box.error.injection.set('ERRINJ_RELAY_TIMEOUT', 0.5)
> > > > > > +@@ -620,3 +620,30 @@ box.error.injection.set('ERRINJ_RELAY_TIMEOUT', 0.5)
> > > > > > box.error.injection.get('ERRINJ_RELAY_TIMEOUT')
> > > > > >     box.error.injection.set('ERRINJ_RELAY_TIMEOUT', 0)
> > > > > > box.error.injection.get('ERRINJ_RELAY_TIMEOUT')
> > > > > >    +
> > > > > >    +--
> > > > > > -+-- gh-4619: make sure that if OOM takes place during rtree recovery,
> > > > > > -+-- Tarantool instance will fail gracefully.
> > > > > > ++-- gh-4619-RTREE-doesn't-handle-OOM-properly
> > > > > >    +--
> > > > > >    +test_run:cmd('create server rtree with script = "box/lua/cfg_rtree.lua"')
> > > > > >    +test_run:cmd("start server rtree")