[Tarantool-patches] [PATCH v4 14/16] sql: remove copying of result in finalizers

[Mergen Imeev via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

This patch removes copying of the result in the finalizers of the SQL
built-in aggregate functions.

Part of #4145
---
 src/box/sql/func.c    | 172 +++++++++++++++++-------------------------
 src/box/sql/sqlInt.h  |  14 +---
 src/box/sql/vdbe.c    |  28 +------
 src/box/sql/vdbeInt.h |   1 -
 src/box/sql/vdbeapi.c |  39 ----------
 5 files changed, 74 insertions(+), 180 deletions(-)

diff --git a/src/box/sql/func.c b/src/box/sql/func.c
index b669402bb..f49d777cc 100644
--- a/src/box/sql/func.c
+++ b/src/box/sql/func.c
@@ -59,47 +59,38 @@ step_sum(struct sql_context *ctx, int argc, struct Mem **argv)
 {
 	assert(argc == 1);
 	(void)argc;
-	assert(mem_is_null(ctx->pMem) || mem_is_num(ctx->pMem));
+	assert(mem_is_null(ctx->pOut) || mem_is_num(ctx->pOut));
 	if (mem_is_null(argv[0]))
 		return;
-	if (mem_is_null(ctx->pMem))
-		return mem_copy_as_ephemeral(ctx->pMem, argv[0]);
-	if (mem_add(ctx->pMem, argv[0], ctx->pMem) != 0)
+	if (mem_is_null(ctx->pOut))
+		return mem_copy_as_ephemeral(ctx->pOut, argv[0]);
+	if (mem_add(ctx->pOut, argv[0], ctx->pOut) != 0)
 		ctx->is_aborted = true;
 }
 
-/** Finalizer for the SUM() function. */
-static void
-fin_sum(struct sql_context *ctx)
-{
-	assert(mem_is_null(ctx->pMem) || mem_is_num(ctx->pMem));
-	mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
-}
-
 /** Implementation of the TOTAL() function. */
 static void
 step_total(struct sql_context *ctx, int argc, struct Mem **argv)
 {
 	assert(argc == 1);
 	(void)argc;
-	assert(mem_is_null(ctx->pMem) || mem_is_num(ctx->pMem));
+	assert(mem_is_null(ctx->pOut) || mem_is_num(ctx->pOut));
 	if (mem_is_null(argv[0]))
 		return;
-	if (mem_is_null(ctx->pMem))
-		mem_set_double(ctx->pMem, 0.0);
-	if (mem_add(ctx->pMem, argv[0], ctx->pMem) != 0)
+	if (mem_is_null(ctx->pOut))
+		mem_set_double(ctx->pOut, 0.0);
+	if (mem_add(ctx->pOut, argv[0], ctx->pOut) != 0)
 		ctx->is_aborted = true;
 }
 
 /** Finalizer for the TOTAL() function. */
-static void
-fin_total(struct sql_context *ctx)
+static int
+fin_total(struct Mem *mem)
 {
-	assert(mem_is_null(ctx->pMem) || mem_is_double(ctx->pMem));
-	if (mem_is_null(ctx->pMem))
-		mem_set_double(ctx->pOut, 0.0);
-	else
-		mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
+	assert(mem_is_null(mem) || mem_is_double(mem));
+	if (mem_is_null(mem))
+		mem_set_double(mem, 0.0);
+	return 0;
 }
 
 /** Implementation of the AVG() function. */
@@ -108,12 +99,12 @@ 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));
+	assert(mem_is_null(ctx->pOut) || mem_is_bin(ctx->pOut));
 	if (mem_is_null(argv[0]))
 		return;
 	struct Mem *mem;
 	uint32_t *count;
-	if (mem_is_null(ctx->pMem)) {
+	if (mem_is_null(ctx->pOut)) {
 		uint32_t size = sizeof(struct Mem) + sizeof(uint32_t);
 		mem = sqlDbMallocRawNN(sql_get(), size);
 		if (mem == NULL) {
@@ -124,10 +115,10 @@ step_avg(struct sql_context *ctx, int argc, struct Mem **argv)
 		mem_create(mem);
 		*count = 1;
 		mem_copy_as_ephemeral(mem, argv[0]);
-		mem_set_bin_allocated(ctx->pMem, (char *)mem, size);
+		mem_set_bin_allocated(ctx->pOut, (char *)mem, size);
 		return;
 	}
-	mem = (struct Mem *)ctx->pMem->z;
+	mem = (struct Mem *)ctx->pOut->z;
 	count = (uint32_t *)(mem + 1);
 	++*count;
 	if (mem_add(mem, argv[0], mem) != 0)
@@ -135,13 +126,15 @@ step_avg(struct sql_context *ctx, int argc, struct Mem **argv)
 }
 
 /** Finalizer for the AVG() function. */
-static void
-fin_avg(struct sql_context *ctx)
+static int
+fin_avg(struct Mem *mem)
 {
-	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;
+	assert(mem_is_null(mem) || mem_is_bin(mem));
+	if (mem_is_null(mem)) {
+		mem_set_null(mem);
+		return 0;
+	}
+	struct Mem *tmp = (struct Mem *)mem->z;
 	uint32_t *count_val = (uint32_t *)(tmp + 1);
 	struct Mem sum;
 	mem_create(&sum);
@@ -150,8 +143,7 @@ fin_avg(struct sql_context *ctx)
 	struct Mem count;
 	mem_create(&count);
 	mem_set_uint(&count, *count_val);
-	if (mem_div(&sum, &count, ctx->pOut) != 0)
-		ctx->is_aborted = true;
+	return mem_div(&sum, &count, mem);
 }
 
 /** Implementation of the COUNT() function. */
@@ -159,22 +151,22 @@ static void
 step_count(struct sql_context *ctx, int argc, struct Mem **argv)
 {
 	assert(argc == 0 || argc == 1);
-	if (mem_is_null(ctx->pMem))
-		mem_set_uint(ctx->pMem, 0);
+	if (mem_is_null(ctx->pOut))
+		mem_set_uint(ctx->pOut, 0);
 	if (argc == 1 && mem_is_null(argv[0]))
 		return;
-	assert(mem_is_uint(ctx->pMem));
-	++ctx->pMem->u.u;
+	assert(mem_is_uint(ctx->pOut));
+	++ctx->pOut->u.u;
 }
 
 /** Finalizer for the COUNT() function. */
-static void
-fin_count(struct sql_context *ctx)
+static int
+fin_count(struct Mem *mem)
 {
-	assert(mem_is_null(ctx->pMem) || mem_is_uint(ctx->pMem));
-	if (mem_is_null(ctx->pMem))
-		return mem_set_uint(ctx->pOut, 0);
-	mem_copy_as_ephemeral(ctx->pOut, ctx->pMem);
+	assert(mem_is_null(mem) || mem_is_uint(mem));
+	if (mem_is_null(mem))
+		mem_set_uint(mem, 0);
+	return 0;
 }
 
 /** Implementation of the MIN() and MAX() functions. */
@@ -184,12 +176,12 @@ step_minmax(struct sql_context *ctx, int argc, struct Mem **argv)
 	assert(argc == 1);
 	(void)argc;
 	if (mem_is_null(argv[0])) {
-		if (!mem_is_null(ctx->pMem))
+		if (!mem_is_null(ctx->pOut))
 			ctx->skipFlag = 1;
 		return;
 	}
-	if (mem_is_null(ctx->pMem)) {
-		if (mem_copy(ctx->pMem, argv[0]) != 0)
+	if (mem_is_null(ctx->pOut)) {
+		if (mem_copy(ctx->pOut, argv[0]) != 0)
 			ctx->is_aborted = true;
 		return;
 	}
@@ -201,22 +193,15 @@ step_minmax(struct sql_context *ctx, int argc, struct Mem **argv)
 	 * the only difference between the two being that the sense of the
 	 * comparison is inverted.
 	 */
-	int cmp = mem_cmp_scalar(ctx->pMem, argv[0], ctx->coll);
+	int cmp = mem_cmp_scalar(ctx->pOut, argv[0], ctx->coll);
 	if ((is_max && cmp < 0) || (!is_max && cmp > 0)) {
-		if (mem_copy(ctx->pMem, argv[0]) != 0)
+		if (mem_copy(ctx->pOut, argv[0]) != 0)
 			ctx->is_aborted = true;
 		return;
 	}
 	ctx->skipFlag = 1;
 }
 
-/** Finalizer for the MIN() and MAX() functions. */
-static void
-fin_minmax(struct sql_context *ctx)
-{
-	mem_copy(ctx->pOut, ctx->pMem);
-}
-
 /** Implementation of the GROUP_CONCAT() function. */
 static void
 step_group_concat(struct sql_context *ctx, int argc, struct Mem **argv)
@@ -226,8 +211,8 @@ step_group_concat(struct sql_context *ctx, int argc, struct Mem **argv)
 	if (mem_is_null(argv[0]))
 		return;
 	assert(mem_is_str(argv[0]) || mem_is_bin(argv[0]));
-	if (mem_is_null(ctx->pMem)) {
-		if (mem_copy(ctx->pMem, argv[0]) != 0)
+	if (mem_is_null(ctx->pOut)) {
+		if (mem_copy(ctx->pOut, argv[0]) != 0)
 			ctx->is_aborted = true;
 		return;
 	}
@@ -244,21 +229,14 @@ step_group_concat(struct sql_context *ctx, int argc, struct Mem **argv)
 		sep = argv[1]->z;
 		sep_len = argv[1]->n;
 	}
-	if (mem_append(ctx->pMem, sep, sep_len) != 0) {
+	if (mem_append(ctx->pOut, sep, sep_len) != 0) {
 		ctx->is_aborted = true;
 		return;
 	}
-	if (mem_append(ctx->pMem, argv[0]->z, argv[0]->n) != 0)
+	if (mem_append(ctx->pOut, argv[0]->z, argv[0]->n) != 0)
 		ctx->is_aborted = true;
 }
 
-/** Finalizer for the GROUP_CONCAT() function. */
-static void
-fin_group_concat(struct sql_context *ctx)
-{
-	mem_copy(ctx->pOut, ctx->pMem);
-}
-
 static const unsigned char *
 mem_as_ustr(struct Mem *mem)
 {
@@ -1941,7 +1919,7 @@ struct sql_func_definition {
 	/** Call implementation with given arguments. */
 	void (*call)(sql_context *ctx, int argc, sql_value **argv);
 	/** Call finalization function for this implementation. */
-	void (*finalize)(sql_context *ctx);
+	int (*finalize)(struct Mem *mem);
 };
 
 /**
@@ -1977,13 +1955,13 @@ static struct sql_func_definition definitions[] = {
 	 NULL},
 
 	{"GROUP_CONCAT", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING,
-	 step_group_concat, fin_group_concat},
+	 step_group_concat, NULL},
 	{"GROUP_CONCAT", 2, {FIELD_TYPE_STRING, FIELD_TYPE_STRING},
-	 FIELD_TYPE_STRING, step_group_concat, fin_group_concat},
+	 FIELD_TYPE_STRING, step_group_concat, NULL},
 	{"GROUP_CONCAT", 1, {FIELD_TYPE_VARBINARY}, FIELD_TYPE_VARBINARY,
-	 step_group_concat, fin_group_concat},
+	 step_group_concat, NULL},
 	{"GROUP_CONCAT", 2, {FIELD_TYPE_VARBINARY, FIELD_TYPE_VARBINARY},
-	 FIELD_TYPE_VARBINARY, step_group_concat, fin_group_concat},
+	 FIELD_TYPE_VARBINARY, step_group_concat, NULL},
 
 	{"HEX", 1, {FIELD_TYPE_VARBINARY}, FIELD_TYPE_STRING, hexFunc, NULL},
 	{"IFNULL", 2, {FIELD_TYPE_ANY, FIELD_TYPE_ANY}, FIELD_TYPE_SCALAR,
@@ -2014,35 +1992,23 @@ static struct sql_func_definition definitions[] = {
 	{"LOWER", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING, LowerICUFunc,
 	 NULL},
 
-	{"MAX", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_minmax,
-	 fin_minmax},
-	{"MAX", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_minmax,
-	 fin_minmax},
-	{"MAX", 1, {FIELD_TYPE_NUMBER}, FIELD_TYPE_NUMBER, step_minmax,
-	 fin_minmax},
+	{"MAX", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_minmax, NULL},
+	{"MAX", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_minmax, NULL},
+	{"MAX", 1, {FIELD_TYPE_NUMBER}, FIELD_TYPE_NUMBER, step_minmax, NULL},
 	{"MAX", 1, {FIELD_TYPE_VARBINARY}, FIELD_TYPE_VARBINARY, step_minmax,
-	 fin_minmax},
-	{"MAX", 1, {FIELD_TYPE_UUID}, FIELD_TYPE_UUID, step_minmax,
-	 fin_minmax},
-	{"MAX", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING, step_minmax,
-	 fin_minmax},
-	{"MAX", 1, {FIELD_TYPE_SCALAR}, FIELD_TYPE_SCALAR, step_minmax,
-	 fin_minmax},
-
-	{"MIN", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_minmax,
-	 fin_minmax},
-	{"MIN", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_minmax,
-	 fin_minmax},
-	{"MIN", 1, {FIELD_TYPE_NUMBER}, FIELD_TYPE_NUMBER, step_minmax,
-	 fin_minmax},
+	 NULL},
+	{"MAX", 1, {FIELD_TYPE_UUID}, FIELD_TYPE_UUID, step_minmax, NULL},
+	{"MAX", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING, step_minmax, NULL},
+	{"MAX", 1, {FIELD_TYPE_SCALAR}, FIELD_TYPE_SCALAR, step_minmax, NULL},
+
+	{"MIN", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_minmax, NULL},
+	{"MIN", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_minmax, NULL},
+	{"MIN", 1, {FIELD_TYPE_NUMBER}, FIELD_TYPE_NUMBER, step_minmax, NULL},
 	{"MIN", 1, {FIELD_TYPE_VARBINARY}, FIELD_TYPE_VARBINARY, step_minmax,
-	 fin_minmax},
-	{"MIN", 1, {FIELD_TYPE_UUID}, FIELD_TYPE_UUID, step_minmax,
-	 fin_minmax},
-	{"MIN", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING, step_minmax,
-	 fin_minmax},
-	{"MIN", 1, {FIELD_TYPE_SCALAR}, FIELD_TYPE_SCALAR, step_minmax,
-	 fin_minmax},
+	 NULL},
+	{"MIN", 1, {FIELD_TYPE_UUID}, FIELD_TYPE_UUID, step_minmax, NULL},
+	{"MIN", 1, {FIELD_TYPE_STRING}, FIELD_TYPE_STRING, step_minmax, NULL},
+	{"MIN", 1, {FIELD_TYPE_SCALAR}, FIELD_TYPE_SCALAR, step_minmax, NULL},
 
 	{"NULLIF", 2, {FIELD_TYPE_ANY, FIELD_TYPE_ANY}, FIELD_TYPE_SCALAR,
 	 nullifFunc, NULL},
@@ -2076,8 +2042,8 @@ static struct sql_func_definition definitions[] = {
 	{"SUBSTR", 3,
 	 {FIELD_TYPE_VARBINARY, FIELD_TYPE_INTEGER, FIELD_TYPE_INTEGER},
 	 FIELD_TYPE_VARBINARY, substrFunc, NULL},
-	{"SUM", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_sum, fin_sum},
-	{"SUM", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_sum, fin_sum},
+	{"SUM", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_INTEGER, step_sum, NULL},
+	{"SUM", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_sum, NULL},
 	{"TOTAL", 1, {FIELD_TYPE_INTEGER}, FIELD_TYPE_DOUBLE, step_total,
 	 fin_total},
 	{"TOTAL", 1, {FIELD_TYPE_DOUBLE}, FIELD_TYPE_DOUBLE, step_total,
@@ -2328,7 +2294,7 @@ sql_built_in_functions_cache_init(void)
 		assert(desc->argc != -1 || dict->argc_min != dict->argc_max);
 		def->param_count = desc->argc;
 		def->returns = desc->result;
-		def->aggregate = desc->finalize == NULL ?
+		def->aggregate = (dict->flags & SQL_FUNC_AGG) == 0 ?
 				 FUNC_AGGREGATE_NONE : FUNC_AGGREGATE_GROUP;
 		def->language = FUNC_LANGUAGE_SQL_BUILTIN;
 		def->name_len = len;
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index 87ba9e067..5fcf5e5a3 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -477,18 +477,6 @@ void
 sql_row_count(struct sql_context *context, MAYBE_UNUSED int unused1,
 	      MAYBE_UNUSED sql_value **unused2);
 
-void *
-sql_aggregate_context(sql_context *,
-			  int nBytes);
-
-/**
- * Allocate or return the aggregate context containing struct MEM for a user
- * function. A new context is allocated on the first call. Subsequent calls
- * return the same context that was returned on prior calls.
- */
-struct Mem *
-sql_context_agg_mem(struct sql_context *context);
-
 int
 sql_column_count(sql_stmt * pStmt);
 
@@ -4372,7 +4360,7 @@ struct func_sql_builtin {
 	 * A VDBE-memory-compatible finalize method
 	 * (is valid only for aggregate function).
 	 */
-	void (*finalize)(sql_context *ctx);
+	int (*finalize)(struct Mem *mem);
 };
 
 /**
diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
index 96eb76244..386430b3b 100644
--- a/src/box/sql/vdbe.c
+++ b/src/box/sql/vdbe.c
@@ -4137,7 +4137,6 @@ case OP_AggStep: {
 	int argc = pOp->p1;
 	sql_context *pCtx;
 	Mem *pMem;
-	Mem t;
 
 	assert(pOp->p4type==P4_FUNCCTX);
 	pCtx = pOp->p4.pCtx;
@@ -4148,8 +4147,8 @@ case OP_AggStep: {
 	 * checks to see if the register array has changed, and if so it
 	 * reinitializes the relavant parts of the sql_context object
 	 */
-	if (pCtx->pMem != pMem) {
-		pCtx->pMem = pMem;
+	if (pCtx->pOut != pMem) {
+		pCtx->pOut = pMem;
 		for(i = 0; i < argc; ++i)
 			pCtx->argv[i] = &aMem[pOp->p2 + i];
 	}
@@ -4161,18 +4160,12 @@ case OP_AggStep: {
 	}
 #endif
 
-	mem_create(&t);
-	pCtx->pOut = &t;
-	pCtx->is_aborted = false;
 	pCtx->skipFlag = 0;
 	assert(pCtx->func->def->language == FUNC_LANGUAGE_SQL_BUILTIN);
 	struct func_sql_builtin *func = (struct func_sql_builtin *)pCtx->func;
 	func->call(pCtx, argc, pCtx->argv);
-	if (pCtx->is_aborted) {
-		mem_destroy(&t);
+	if (pCtx->is_aborted)
 		goto abort_due_to_error;
-	}
-	assert(mem_is_null(&t));
 	if (pCtx->skipFlag) {
 		assert(pOp[-1].opcode == OP_SkipLoad);
 		i = pOp[-1].p1;
@@ -4199,20 +4192,7 @@ case OP_AggFinal: {
 	struct func_sql_builtin *func = (struct func_sql_builtin *)pOp->p4.func;
 	struct Mem *pIn1 = &aMem[pOp->p1];
 
-	struct sql_context ctx;
-	memset(&ctx, 0, sizeof(ctx));
-	struct Mem t;
-	mem_create(&t);
-	ctx.pOut = &t;
-	ctx.pMem = pIn1;
-	ctx.func = pOp->p4.func;
-	func->finalize(&ctx);
-	assert((pIn1->flags & MEM_Dyn) == 0);
-	if (pIn1->szMalloc > 0)
-		sqlDbFree(pIn1->db, pIn1->zMalloc);
-	memcpy(pIn1, &t, sizeof(t));
-
-	if (ctx.is_aborted)
+	if (func->finalize != NULL && func->finalize(pIn1) != 0)
 		goto abort_due_to_error;
 	UPDATE_MAX_BLOBSIZE(pIn1);
 	if (sqlVdbeMemTooBig(pIn1) != 0)
diff --git a/src/box/sql/vdbeInt.h b/src/box/sql/vdbeInt.h
index b9a18f1a1..5e2692d06 100644
--- a/src/box/sql/vdbeInt.h
+++ b/src/box/sql/vdbeInt.h
@@ -172,7 +172,6 @@ struct sql_context {
 	Mem *pOut;		/* The return value is stored here */
 	/* A pointer to function implementation. */
 	struct func *func;
-	Mem *pMem;		/* Memory cell used to store aggregate context */
 	struct coll *coll;
 	/*
 	 * True, if an error occurred during the execution of the
diff --git a/src/box/sql/vdbeapi.c b/src/box/sql/vdbeapi.c
index 65f51c21c..8f7e28ffb 100644
--- a/src/box/sql/vdbeapi.c
+++ b/src/box/sql/vdbeapi.c
@@ -330,45 +330,6 @@ sql_context_db_handle(sql_context * p)
 	return p->pOut->db;
 }
 
-/*
- * Allocate or return the aggregate context for a user function.  A new
- * context is allocated on the first call.  Subsequent calls return the
- * same context that was returned on prior calls.
- */
-void *
-sql_aggregate_context(sql_context * p, int nByte)
-{
-	assert(p != NULL && p->func != NULL);
-	assert(p->func->def->language == FUNC_LANGUAGE_SQL_BUILTIN);
-	assert(p->func->def->aggregate == FUNC_AGGREGATE_GROUP);
-	if (!mem_is_agg(p->pMem) && mem_set_agg(p->pMem, p->func, nByte) != 0)
-		return NULL;
-	void *accum;
-	if (mem_get_agg(p->pMem, &accum) != 0)
-		return NULL;
-	return accum;
-}
-
-struct Mem *
-sql_context_agg_mem(struct sql_context *ctx)
-{
-	assert(ctx != NULL && ctx->func != NULL);
-	assert(ctx->func->def->language == FUNC_LANGUAGE_SQL_BUILTIN);
-	assert(ctx->func->def->aggregate == FUNC_AGGREGATE_GROUP);
-	struct Mem *mem;
-	if (!mem_is_agg(ctx->pMem)) {
-		if (mem_set_agg(ctx->pMem, ctx->func, sizeof(*mem)) != 0)
-			return NULL;
-		if (mem_get_agg(ctx->pMem, (void **)&mem) != 0)
-			return NULL;
-		mem_create(mem);
-		return mem;
-	}
-	if (mem_get_agg(ctx->pMem, (void **)&mem) != 0)
-		return NULL;
-	return mem;
-}
-
 /*
  * Return the number of columns in the result set for the statement pStmt.
  */
-- 
2.25.1