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From: Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>
To: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org
Subject: Re: [Tarantool-patches] [PATCH v4 10/16] sql: refactor AVG() function
Date: Tue, 5 Oct 2021 12:48:06 +0300
Message-ID: <20211005094806.GE55311@tarantool.org> (raw)
In-Reply-To: <6dfd69ff-a807-b0d5-4896-4b5118ee2679@tarantool.org>

Thank you for the review! My answer below.

On Mon, Oct 04, 2021 at 11:53:19PM +0200, Vladislav Shpilevoy wrote:
> Thanks for the fixes!
> 
> > diff --git a/src/box/sql/func.c b/src/box/sql/func.c
> > index 8a9de1254..94ec811ef 100644
> > --- a/src/box/sql/func.c
> > +++ b/src/box/sql/func.c
> > @@ -102,6 +102,58 @@ fin_total(struct sql_context *ctx)
> 
> <...>
> 
> > +
> > +/** Finalizer for the AVG() function. */
> > +static void
> > +fin_avg(struct sql_context *ctx)
> > +{
> > +	assert(mem_is_null(ctx->pMem) || mem_is_bin(ctx->pMem));
> > +	if (mem_is_null(ctx->pMem))
> > +		return mem_set_null(ctx->pOut);
> > +	struct Mem *tmp = (struct Mem *)ctx->pMem->z;
> > +	uint32_t *count_val = (uint32_t *)(tmp + 1);
> > +	struct Mem sum;
> > +	mem_create(&sum);
> > +	mem_copy_as_ephemeral(&sum, tmp);
> > +	mem_destroy(tmp);
> > +	struct Mem count;
> > +	mem_create(&count);
> > +	mem_set_uint(&count, *count_val);
> > +	if (mem_div(&sum, &count, ctx->pOut) != 0)
> > +		ctx->is_aborted = true;
> 
> Consider this:
> 
> ====================
> @@ -141,17 +141,14 @@ fin_avg(struct sql_context *ctx)
>  	assert(mem_is_null(ctx->pMem) || mem_is_bin(ctx->pMem));
>  	if (mem_is_null(ctx->pMem))
>  		return mem_set_null(ctx->pOut);
> -	struct Mem *tmp = (struct Mem *)ctx->pMem->z;
> -	uint32_t *count_val = (uint32_t *)(tmp + 1);
> -	struct Mem sum;
> -	mem_create(&sum);
> -	mem_copy_as_ephemeral(&sum, tmp);
> -	mem_destroy(tmp);
> +	struct Mem *sum = (struct Mem *)ctx->pMem->z;
> +	uint32_t *count_val = (uint32_t *)(sum + 1);
>  	struct Mem count;
>  	mem_create(&count);
>  	mem_set_uint(&count, *count_val);
>  	if (mem_div(&sum, &count, ctx->pOut) != 0)
>  		ctx->is_aborted = true;
> +	mem_destroy(sum);
>  }
This will work, however, I think it will create some unnecessary restrictions
due to changes with pMem and pOut in a few patches. I suggest to apply part of
you diff with exception of mem_destroy(), which I sugget to replace by assert().
We have full control over this tmp/sum mem and we know, that there will be no
memory to free, so assert should be enough.

What do you think of this diff?

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index a811e55f9..8213704e9 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -141,16 +141,13 @@ fin_avg(struct sql_context *ctx)
 	assert(mem_is_null(ctx->pMem) || mem_is_bin(ctx->pMem));
 	if (mem_is_null(ctx->pMem))
 		return mem_set_null(ctx->pOut);
-	struct Mem *tmp = (struct Mem *)ctx->pMem->z;
-	uint32_t *count_val = (uint32_t *)(tmp + 1);
-	struct Mem sum;
-	mem_create(&sum);
-	mem_copy_as_ephemeral(&sum, tmp);
-	mem_destroy(tmp);
+	struct Mem *sum = (struct Mem *)ctx->pMem->z;
+	uint32_t *count_val = (uint32_t *)(sum + 1);
+	assert(!VdbeMemDynamic(sum) && sum->szMalloc == 0);
 	struct Mem count;
 	mem_create(&count);
 	mem_set_uint(&count, *count_val);
-	if (mem_div(&sum, &count, ctx->pOut) != 0)
+	if (mem_div(sum, &count, ctx->pOut) != 0)
 		ctx->is_aborted = true;
 }
 

  reply	other threads:[~2021-10-05  9:48 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01 12:48 [Tarantool-patches] [PATCH v4 00/16] sql: refactor aggregate functions Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 01/16] sql: remove MEM_Zero flag from struct MEM Mergen Imeev via Tarantool-patches
2021-10-04 21:51   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05  8:46     ` Mergen Imeev via Tarantool-patches
2021-10-05  9:42       ` Mergen Imeev via Tarantool-patches
2021-10-05 12:28         ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 02/16] sql: fix possible undefined behavior during cast Mergen Imeev via Tarantool-patches
2021-10-04 21:52   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05  9:00     ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 03/16] sql: use register P1 for number of arguments Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 04/16] sql: remove AggStep0 and OP_BuiltinFunction0 Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 05/16] sql: move collation to struct sql_context Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 06/16] sql: introduce mem_append() Mergen Imeev via Tarantool-patches
2021-10-04 21:52   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05  9:32     ` Mergen Imeev via Tarantool-patches
2021-10-11 21:50       ` Vladislav Shpilevoy via Tarantool-patches
2021-10-19 10:49         ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 07/16] sql: remove sql_vdbemem_finalize() Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 08/16] sql: refactor SUM() function Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 09/16] sql: refactor TOTAL() function Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 10/16] sql: refactor AVG() function Mergen Imeev via Tarantool-patches
2021-10-04 21:53   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05  9:48     ` Mergen Imeev via Tarantool-patches [this message]
2021-10-11 21:50       ` Vladislav Shpilevoy via Tarantool-patches
2021-10-19 11:14         ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 11/16] sql: refactor COUNT() function Mergen Imeev via Tarantool-patches
2021-10-04 21:53   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05  9:55     ` Mergen Imeev via Tarantool-patches
2021-10-11 21:51       ` Vladislav Shpilevoy via Tarantool-patches
2021-10-19 11:17         ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 12/16] sql: refactor MIN() and MAX() functions Mergen Imeev via Tarantool-patches
2021-10-04 21:54   ` Vladislav Shpilevoy via Tarantool-patches
2021-10-05 10:07     ` Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 13/16] sql: refactor GROUP_CONCAT() function Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 14/16] sql: remove copying of result in finalizers Mergen Imeev via Tarantool-patches
2021-10-01 12:48 ` [Tarantool-patches] [PATCH v4 15/16] sql: remove MEM_TYPE_AGG Mergen Imeev via Tarantool-patches
2021-10-01 12:49 ` [Tarantool-patches] [PATCH v4 16/16] sql: remove field argv from struct sql_context Mergen Imeev via Tarantool-patches
2021-10-25 20:58 ` [Tarantool-patches] [PATCH v4 00/16] sql: refactor aggregate functions Vladislav Shpilevoy via Tarantool-patches
2021-10-26 10:34 Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 10/16] sql: refactor AVG() function Mergen Imeev via Tarantool-patches

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