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From: Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>
To: kyukhin@tarantool.org
Cc: tarantool-patches@dev.tarantool.org
Subject: [Tarantool-patches] [PATCH v4 10/16] sql: refactor AVG() function
Date: Tue, 26 Oct 2021 13:34:22 +0300	[thread overview]
Message-ID: <5606a33ae4ca842b23774b0d2e4cc33c0c6a0ed0.1635244212.git.imeevma@gmail.com> (raw)
In-Reply-To: <cover.1635244212.git.imeevma@gmail.com>

Part of #4145
---
 src/box/sql/func.c | 116 ++++++++++++++++++++-------------------------
 src/box/sql/mem.h  |   8 ++++
 2 files changed, 59 insertions(+), 65 deletions(-)

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index c3c7ebec0..8be553110 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -102,6 +102,55 @@ fin_total(struct sql_context *ctx)
 		mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
 }
 
+/** Implementation of the AVG() function. */
+static void
+step_avg(struct sql_context *ctx, int argc, struct Mem **argv)
+{
+	assert(argc == 1);
+	(void)argc;
+	assert(mem_is_null(ctx->pMem) || mem_is_bin(ctx->pMem));
+	if (mem_is_null(argv[0]))
+		return;
+	struct Mem *mem;
+	uint32_t *count;
+	if (mem_is_null(ctx->pMem)) {
+		uint32_t size = sizeof(struct Mem) + sizeof(uint32_t);
+		mem = sqlDbMallocRawNN(sql_get(), size);
+		if (mem == NULL) {
+			ctx->is_aborted = true;
+			return;
+		}
+		count = (uint32_t *)(mem + 1);
+		mem_create(mem);
+		*count = 1;
+		mem_copy_as_ephemeral(mem, argv[0]);
+		mem_set_bin_allocated(ctx->pMem, (char *)mem, size);
+		return;
+	}
+	mem = (struct Mem *)ctx->pMem->z;
+	count = (uint32_t *)(mem + 1);
+	++*count;
+	if (mem_add(mem, argv[0], mem) != 0)
+		ctx->is_aborted = true;
+}
+
+/** 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 *sum = (struct Mem *)ctx->pMem->z;
+	uint32_t *count_val = (uint32_t *)(sum + 1);
+	assert(mem_is_trivial(sum));
+	struct Mem count;
+	mem_create(&count);
+	mem_set_uint(&count, *count_val);
+	if (mem_div(sum, &count, ctx->pOut) != 0)
+		ctx->is_aborted = true;
+}
+
 static const unsigned char *
 mem_as_ustr(struct Mem *mem)
 {
@@ -1663,69 +1712,6 @@ soundexFunc(sql_context * context, int argc, sql_value ** argv)
 	}
 }
 
-/*
- * An instance of the following structure holds the context of a
- * sum() or avg() aggregate computation.
- */
-typedef struct SumCtx SumCtx;
-struct SumCtx {
-	struct Mem mem;
-	uint32_t count;
-};
-
-/*
- * Routines used to compute the sum, average, and total.
- *
- * The SUM() function follows the (broken) SQL standard which means
- * that it returns NULL if it sums over no inputs.  TOTAL returns
- * 0.0 in that case.  In addition, TOTAL always returns a float where
- * SUM might return an integer if it never encounters a floating point
- * value.  TOTAL never fails, but SUM might through an exception if
- * it overflows an integer.
- */
-static void
-sum_step(struct sql_context *context, int argc, sql_value **argv)
-{
-	assert(argc == 1);
-	UNUSED_PARAMETER(argc);
-	struct SumCtx *p = sql_aggregate_context(context, sizeof(*p));
-	if (p == NULL) {
-		context->is_aborted = true;
-		return;
-	}
-	if (p->count == 0) {
-		mem_create(&p->mem);
-		assert(context->func->def->returns == FIELD_TYPE_INTEGER ||
-		       context->func->def->returns == FIELD_TYPE_DOUBLE);
-		if (context->func->def->returns == FIELD_TYPE_INTEGER)
-			mem_set_uint(&p->mem, 0);
-		else
-			mem_set_double(&p->mem, 0.0);
-	}
-	if (argv[0]->type == MEM_TYPE_NULL)
-		return;
-	++p->count;
-	assert(mem_is_num(argv[0]));
-	if (mem_add(&p->mem, argv[0], &p->mem) != 0)
-		context->is_aborted = true;
-}
-
-static void
-avgFinalize(sql_context * context)
-{
-	SumCtx *p;
-	p = sql_aggregate_context(context, 0);
-	if (p == NULL || p->count == 0) {
-		mem_set_null(context->pOut);
-		return;
-	}
-	struct Mem mem;
-	mem_create(&mem);
-	mem_set_uint(&mem, p->count);
-	if (mem_div(&p->mem, &mem, context->pOut) != 0)
-		context->is_aborted = true;
-}
-
 /*
  * The following structure keeps track of state information for the
  * count() aggregate function.
@@ -2022,8 +2008,8 @@ struct sql_func_definition {
 static struct sql_func_definition definitions[] = {
 	{"ABS", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, absFunc, NULL},
 	{"ABS", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, absFunc, NULL},
-	{"AVG", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, sum_step, avgFinalize},
-	{"AVG", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, sum_step, avgFinalize},
+	{"AVG", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_avg, fin_avg},
+	{"AVG", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_avg, fin_avg},
 	{"CHAR", -1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_STRING, charFunc, NULL},
 	{"CHAR_LENGTH", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_INTEGER, lengthFunc,
 	 NULL},
diff --git a/src/box/sql/mem.h b/src/box/sql/mem.h
index 7d5a750f5..52a63949a 100644
--- a/src/box/sql/mem.h
+++ b/src/box/sql/mem.h
@@ -237,6 +237,14 @@ mem_is_allocated(const struct Mem *mem)
 	return mem_is_bytes(mem) && mem->z == mem->zMalloc;
 }
 
+/** Return TRUE if MEM does not need to be freed or destroyed. */
+static inline bool
+mem_is_trivial(const struct Mem *mem)
+{
+	return mem->szMalloc == 0 && (mem->flags & MEM_Dyn) == 0 &&
+	       (mem->type & (MEM_TYPE_FRAME | MEM_TYPE_AGG)) == 0;
+}
+
 static inline bool
 mem_is_cleared(const struct Mem *mem)
 {
-- 
2.25.1


  parent reply	other threads:[~2021-10-26 10:39 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-26 10:34 [Tarantool-patches] [PATCH v4 00/16] sql: refactor aggregate functions Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 01/16] sql: remove MEM_Zero flag from struct MEM Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 02/16] sql: fix possible undefined behavior during cast Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 03/16] sql: use register P1 for number of arguments Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 04/16] sql: remove AggStep0 and OP_BuiltinFunction0 Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 05/16] sql: move collation to struct sql_context Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 06/16] sql: introduce mem_append() Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 07/16] sql: remove sql_vdbemem_finalize() Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 08/16] sql: refactor SUM() function Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 09/16] sql: refactor TOTAL() function Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` Mergen Imeev via Tarantool-patches [this message]
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 11/16] sql: refactor COUNT() function Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 12/16] sql: refactor MIN() and MAX() functions Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 13/16] sql: refactor GROUP_CONCAT() function Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 14/16] sql: remove copying of result in finalizers Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 15/16] sql: remove MEM_TYPE_AGG Mergen Imeev via Tarantool-patches
2021-10-26 10:34 ` [Tarantool-patches] [PATCH v4 16/16] sql: remove field argv from struct sql_context Mergen Imeev via Tarantool-patches
2021-11-02 10:36 ` [Tarantool-patches] [PATCH v4 00/16] sql: refactor aggregate functions Kirill Yukhin via Tarantool-patches
  -- strict thread matches above, loose matches on Subject: below --
2021-10-01 12:48 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
2021-10-11 21:50       ` Vladislav Shpilevoy via Tarantool-patches
2021-10-19 11:14         ` Mergen Imeev via Tarantool-patches

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