[tarantool-patches] Re: [PATCH v2 2/2] Fixed lost format on update and upsert operations.

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Hello. See my 19 comments below.

1. Build fails:

/Users/v.shpilevoy/Work/Repositories/tarantool/src/box/lua/tuple.c:405:6: 
error: variable 'new_tuple' is used uninitialized whenever 'if' 
condition is true [-Werror,-Wsometimes-uninitialized]
         if (new_data == NULL) {
             ^~~~~~~~~~~~~~~~
/Users/v.shpilevoy/Work/Repositories/tarantool/src/box/lua/tuple.c:420:6: 
note: uninitialized use occurs here
         if (new_tuple == NULL)
             ^~~~~~~~~
/Users/v.shpilevoy/Work/Repositories/tarantool/src/box/lua/tuple.c:405:2: 
note: remove the 'if' if its condition is always false
         if (new_data == NULL) {
         ^~~~~~~~~~~~~~~~~~~~~~~
/Users/v.shpilevoy/Work/Repositories/tarantool/src/box/lua/tuple.c:409:2: 
note: variable 'new_tuple' is declared here
         struct tuple *new_tuple = tuple_new(box_tuple_format_default(),
         ^
1 error generated.


On 10/04/2018 13:23, Kirill Shcherbatov wrote:
>  From c268dedd32ed124fb25c46e3fb0bf1cd507fda62 Mon Sep 17 00:00:00 2001
> From: Kirill Shcherbatov <kshcherbatov@tarantool.org>
> Date: Fri, 6 Apr 2018 19:21:32 +0300
> Subject: [PATCH] Fixed lost format on update and upsert operations.

2. Please, describe a problem, which the patch solves.

> 
> Fixes #3051
> ---
>   src/box/lua/tuple.c      |  31 +++++++++++--
>   src/box/memtx_tuple.cc   |   1 +
>   src/box/tuple.c          |  31 ++++++++-----
>   src/box/tuple.h          |   2 +-
>   src/box/tuple_format.h   |   5 +-
>   src/box/vy_stmt.c        |   7 +++
>   src/box/vy_stmt.h        |   9 ++++
>   test/box/update.result   | 118 +++++++++++++++++++++++++++++++++++++++++++++++
>   test/box/update.test.lua |  41 ++++++++++++++++
>   9 files changed, 226 insertions(+), 19 deletions(-)
> 
> diff --git a/src/box/lua/tuple.c b/src/box/lua/tuple.c
> index 47b33c9..9bb62b0 100644
> --- a/src/box/lua/tuple.c
> +++ b/src/box/lua/tuple.c
> @@ -36,6 +36,7 @@
>   #include <small/ibuf.h>
>   #include <small/region.h>
>   #include <fiber.h>
> +#include <box/tuple_update.h>

3. Do not put project headers in <>.

>   
>   #include "box/tuple.h"
>   #include "box/tuple_convert.h"
> @@ -390,15 +391,35 @@ lbox_tuple_transform(struct lua_State *L)
>   	}
>   	mpstream_flush(&stream);
>   
> -	/* Execute tuple_update */
> -	struct tuple *new_tuple =
> -		box_tuple_update(tuple, buf->buf, buf->buf + ibuf_used(buf));
> +	uint32_t new_size = 0, bsize;
> +	const char *old_data = tuple_data_range(tuple, &bsize);
> +	struct region *region = &fiber()->gc;
> +	size_t used = region_used(region);
> +	const char *new_data = tuple_update_execute(region_aligned_alloc_cb,
> +	                                            region,
> +	                                            buf->buf,
> +	                                            buf->buf + ibuf_used(buf),
> +	                                            old_data,
> +	                                            old_data + bsize,
> +	                                            &new_size, 1, NULL);

4. Please, do not put each argument on a separate line when possible.

> +	if (new_data == NULL) {
> +		region_truncate(region, used);
> +		goto error;

5. You can remove goto error, if instead of new_data == NULL with do

if new_data != NULL then new_tuple = tuple_new(...) end
region_truncate(...)
if new_tuple == NULL then lua_error(...) end

> +	}
> +	struct tuple *new_tuple = tuple_new(box_tuple_format_default(),
> +	                                    new_data, new_data + new_size);
> +	region_truncate(region, used);
>   	if (new_tuple == NULL)
> -		luaT_error(L);
> -	/* box_tuple_update() doesn't leak on exception, see public API doc */
> +		goto error;
> +	tuple_bless(new_tuple);

6. AFAIK tuple_bless here is not needed, because lua_pushtuple already 
does tuple reference count increment.

> +
>   	luaT_pushtuple(L, new_tuple);
>   	ibuf_reset(buf);
>   	return 1;
> +error:
> +	if (new_tuple == NULL)
> +		luaT_error(L);
> +	return 0;

7. Error label will be removed, but please answer yourself why error 
label can return non-error code.

>   }
>   
>   /**
> diff --git a/src/box/memtx_tuple.cc b/src/box/memtx_tuple.cc
> index 70453bd..1990bdf 100644
> --- a/src/box/memtx_tuple.cc
> +++ b/src/box/memtx_tuple.cc
> diff --git a/src/box/tuple.c b/src/box/tuple.c
> index d4760f3..cb57d81 100644
> --- a/src/box/tuple.c
> +++ b/src/box/tuple.c
> @@ -61,15 +61,19 @@ struct tuple_format *tuple_format_runtime;
>   static void
>   runtime_tuple_delete(struct tuple_format *format, struct tuple *tuple);
>   
> +struct tuple *

8. Please, make this function static.

> +runtime_tuple_new(struct tuple_format *format, const char *data, const char *end);
> +
>   /** A virtual method table for tuple_format_runtime */
>   static struct tuple_format_vtab tuple_format_runtime_vtab = {
>   	runtime_tuple_delete,
> +	runtime_tuple_new,
>   };
>   
>   struct tuple *
> -tuple_new(struct tuple_format *format, const char *data, const char *end)
> +runtime_tuple_new(struct tuple_format *format, const char *data, const char *end)
>   {
> -	assert(format->vtab.destroy == tuple_format_runtime_vtab.destroy);
> +	assert(format->vtab.tuple_delete == tuple_format_runtime_vtab.tuple_delete);
>   
>   	mp_tuple_assert(data, end);
>   	size_t data_len = end - data;
> @@ -102,7 +106,7 @@ tuple_new(struct tuple_format *format, const char *data, const char *end)
>   static void
>   runtime_tuple_delete(struct tuple_format *format, struct tuple *tuple)
>   {
> -	assert(format->vtab.destroy == tuple_format_runtime_vtab.destroy);
> +	assert(format->vtab.tuple_delete == tuple_format_runtime_vtab.tuple_delete);
>   	say_debug("%s(%p)", __func__, tuple);
>   	assert(tuple->refs == 0);
>   	size_t total = sizeof(struct tuple) + tuple_format_meta_size(format) +
> @@ -147,6 +151,12 @@ tuple_validate_raw(struct tuple_format *format, const char *tuple)
>   	return 0;
>   }
>   
> +struct tuple *

9. Please make this wrapper be in tuple.h, static inline and add a 
comment. It is a common practice for our virtual methods wrappers. See 
key_def.h for examples.

> +tuple_new(struct tuple_format *format, const char *data, const char *end)
> +{
> +	return format->vtab.tuple_new(format, data, end);
> +}
> +
>   /**
>    * Incremented on every snapshot and is used to distinguish tuples
>    * which were created after start of a snapshot (these tuples can
> @@ -396,22 +406,20 @@ box_tuple_t *
>   box_tuple_update(const box_tuple_t *tuple, const char *expr,
>   		 const char *expr_end)
>   {
> -	struct tuple_format *format = tuple_format_runtime;
> -
>   	uint32_t new_size = 0, bsize;
>   	const char *old_data = tuple_data_range(tuple, &bsize);
>   	struct region *region = &fiber()->gc;
>   	size_t used = region_used(region);
>   	const char *new_data =
>   		tuple_update_execute(region_aligned_alloc_cb, region, expr,
> -				     expr_end, old_data, old_data + bsize,
> -				     &new_size, 1, NULL);
> +		                     expr_end, old_data, old_data + bsize,
> +		                     &new_size, 1, NULL);

10. Garbage diff.

>   	if (new_data == NULL) {
>   		region_truncate(region, used);
>   		return NULL;
>   	}
> -
> -	struct tuple *ret = tuple_new(format, new_data, new_data + new_size);
> +	struct tuple *ret = tuple_new(tuple_format(tuple), new_data,
> +	                              new_data + new_size);

11. Same.

>   	region_truncate(region, used);
>   	if (ret != NULL)
>   		return tuple_bless(ret);
> @@ -422,8 +430,6 @@ box_tuple_t *
>   box_tuple_upsert(const box_tuple_t *tuple, const char *expr,
>   		 const char *expr_end)
>   {
> -	struct tuple_format *format = tuple_format_runtime;

12. Same.

> -
>   	uint32_t new_size = 0, bsize;
>   	const char *old_data = tuple_data_range(tuple, &bsize);
>   	struct region *region = &fiber()->gc;
> @@ -437,7 +443,8 @@ box_tuple_upsert(const box_tuple_t *tuple, const char *expr,
>   		return NULL;
>   	}
>   
> -	struct tuple *ret = tuple_new(format, new_data, new_data + new_size);
> +	struct tuple *ret = tuple_new(tuple_format(tuple),
> +	                              new_data, new_data + new_size);

13. Same.

>   	region_truncate(region, used);
>   	if (ret != NULL)
>   		return tuple_bless(ret);
> diff --git a/src/box/tuple.h b/src/box/tuple.h
> index 6ebedf5..d8138e2 100644
> --- a/src/box/tuple.h
> +++ b/src/box/tuple.h
> @@ -445,7 +445,7 @@ tuple_delete(struct tuple *tuple)
>   	say_debug("%s(%p)", __func__, tuple);
>   	assert(tuple->refs == 0);
>   	struct tuple_format *format = tuple_format(tuple);
> -	format->vtab.destroy(format, tuple);
> +	format->vtab.tuple_delete(format, tuple);
>   }
>   
>   /**
> diff --git a/src/box/tuple_format.h b/src/box/tuple_format.h
> index d35182d..cc727ec 100644
> --- a/src/box/tuple_format.h
> +++ b/src/box/tuple_format.h
> @@ -68,7 +68,10 @@ struct tuple_format;
>   struct tuple_format_vtab {
>   	/** Free allocated tuple using engine-specific memory allocator. */
>   	void
> -	(*destroy)(struct tuple_format *format, struct tuple *tuple);
> +	(*tuple_delete)(struct tuple_format *format, struct tuple *tuple);
> +	/** Allocates a new tuple on the same allocator and with the same format. */

14. Out of 66 symbols.

> +	struct tuple*
> +	(*tuple_new)(struct tuple_format *format, const char *data, const char *end);

15. Out of 80 symbols.

>   };
>   
>   /** Tuple field meta information for tuple_format. */
> diff --git a/src/box/vy_stmt.c b/src/box/vy_stmt.c
> index 84182e7..3135c58 100644
> --- a/src/box/vy_stmt.c
> +++ b/src/box/vy_stmt.c
> @@ -47,6 +47,7 @@
>   
>   struct tuple_format_vtab vy_tuple_format_vtab = {
>   	vy_tuple_delete,
> +	vy_tuple_new,
>   };
>   
>   size_t vy_max_tuple_size = 1024 * 1024;
> @@ -69,6 +70,12 @@ vy_tuple_delete(struct tuple_format *format, struct tuple *tuple)
>   	free(tuple);
>   }
>   
> +struct tuple *

16. Static.

> +vy_tuple_new(struct tuple_format *format, const char *data, const char *end)
> +{
> +	return vy_stmt_new_insert(format, data, end);
> +}
> +
>   /**
>    * Allocate a vinyl statement object on base of the struct tuple
>    * with malloc() and the reference counter equal to 1.
> diff --git a/src/box/vy_stmt.h b/src/box/vy_stmt.h
> index a33739d..efc99c8 100644
> --- a/src/box/vy_stmt.h
> +++ b/src/box/vy_stmt.h
> @@ -206,6 +206,15 @@ void
>   vy_tuple_delete(struct tuple_format *format, struct tuple *tuple);
>   
>   /**
> + * Create the tuple of a vinyl space.
> + * @param format Target tuple format.
> + * @param data Target tuple data.
> + * @param size Size of the data.
> + */
> +struct tuple *
> +vy_tuple_new(struct tuple_format *format, const char *data, const char *end);

17. Used in vy_stmt.c only. You can remove it from the header.

> diff --git a/test/box/update.test.lua b/test/box/update.test.lua
> index c455bc1..1dc1751 100644
> --- a/test/box/update.test.lua
> +++ b/test/box/update.test.lua
> @@ -269,3 +269,44 @@ t:update({{'=', 3, map}})
>   s:update(1, {{'=', 3, map}})
>   
>   s:drop()
> +
> +--
> +-- gh-3051 Lost format while tuple update
> +--
> +format = {}
> +format[1] = {name = 'KEY', type = 'unsigned'}
> +format[2] = {name = 'VAL', type = 'string'}
> +s = box.schema.create_space('tst_sample', {format = format})
> +pk = s:create_index('pk')
> +s:insert({1, 'sss'})
> +aa = box.space.tst_sample:get(1)
> +aa.VAL
> +aa = aa:update({{'=',2,'ssss'}})
> +collectgarbage()

18. Even if a tuple leaks, this code does not detect it. Either create a 
correct check via Lua weak references (see __mode = 'k'/'v' and 
net.box.test.lua), or remove this code.

> +aa.VAL
> +s:drop()
> +aa = nil
> +collectgarbage()
> +
> +s = box.schema.space.create('tst_sample', {engine = 'vinyl', format = format})

19. When you need multiple engines for the same test, you must use 
engine/ test suite.

> +pk = s:create_index('pk')
> +s:insert({1, 'sss'})
> +aa = box.space.tst_sample:get(1)
> +aa.VAL
> +aa = aa:update({{'=',2,'ssss'}})
> +collectgarbage()
> +aa.VAL
> +s:drop()
> +aa = nil
> +collectgarbage()
> +
> +-- test transform integrity
> +space = box.schema.space.create('tweedledum')
> +tmp = space:create_index('primary', { type = 'hash', parts = {1, 'string'}, unique = true })
> +t = space:insert{'1', '2', '3', '4', '5', '6', '7'}
> +t:transform(-1, 1)
> +n = 2000
> +tab = {}; for i=1,n,1 do table.insert(tab, i) end
> +t = box.tuple.new(tab)
> +t:transform(1, n - 1)
> +t = nil
>