pgbench_pow_v6.patch

From b12a7a37b1af1ede1aa9d5d88d0918808c54e19f Mon Sep 17 00:00:00 2001
From: Raul Marin <rmrodriguez@cartodb.com>
Date: Fri, 1 Dec 2017 10:49:17 +0100
Subject: [PATCH] Add pow() support to pgbench

---
 doc/src/sgml/ref/pgbench.sgml                |  7 ++++
 src/bin/pgbench/exprparse.y                  |  3 ++
 src/bin/pgbench/pgbench.c                    | 62 ++++++++++++++++++++++++++++
 src/bin/pgbench/pgbench.h                    |  3 +-
 src/bin/pgbench/t/001_pgbench_with_server.pl | 16 ++++++-
 5 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/ref/pgbench.sgml b/doc/src/sgml/ref/pgbench.sgml
index 94b495e606..769e604dd6 100644
--- a/doc/src/sgml/ref/pgbench.sgml
+++ b/doc/src/sgml/ref/pgbench.sgml
@@ -1099,6 +1099,13 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
        <entry><literal>sqrt(2.0)</literal></entry>
        <entry><literal>1.414213562</literal></entry>
       </row>
+      <row>
+       <entry><literal><function>pow(<replaceable>x</replaceable>, <replaceable>y</replaceable>)</function></literal></entry>
+       <entry>integer if <replaceable>x</replaceable> and <replaceable>y</replaceable> are integers and <literal><replaceable>y</replaceable> >= 0</literal>, else double</entry>
+       <entry>Numeric exponentiation</entry>
+       <entry><literal>pow(2.0, 10)</literal></entry>
+       <entry><literal>1024.0</literal></entry>
+      </row>
      </tbody>
      </tgroup>
    </table>
diff --git a/src/bin/pgbench/exprparse.y b/src/bin/pgbench/exprparse.y
index b3a2d9bfd3..4db3b215ab 100644
--- a/src/bin/pgbench/exprparse.y
+++ b/src/bin/pgbench/exprparse.y
@@ -191,6 +191,9 @@ static const struct
 	{
 		"random_exponential", 3, PGBENCH_RANDOM_EXPONENTIAL
 	},
+	{
+		"pow", 2, PGBENCH_POW
+	},
 	/* keep as last array element */
 	{
 		NULL, 0, 0
diff --git a/src/bin/pgbench/pgbench.c b/src/bin/pgbench/pgbench.c
index bd96eae5e6..5a5197cf63 100644
--- a/src/bin/pgbench/pgbench.c
+++ b/src/bin/pgbench/pgbench.c
@@ -746,6 +746,27 @@ getPoissonRand(TState *thread, int64 center)
 	return (int64) (-log(uniform) * ((double) center) + 0.5);
 }
 
+ /*
+  * pow() for integer values with exp >= 0. Matches SQL pow() behaviour
+  */
+static int64
+ipow(int64 base, int64 exp)
+{
+	int64 result = 1;
+
+	Assert(exp >= 0);
+
+	while (exp)
+	{
+		if (exp & 1)
+			result *= base;
+		exp >>= 1;
+		base *= base;
+	}
+
+	return result;
+}
+
 /*
  * Initialize the given SimpleStats struct to all zeroes
  */
@@ -1673,6 +1694,47 @@ evalFunc(TState *thread, CState *st,
 				return true;
 			}
 
+		case PGBENCH_POW:
+			{
+				PgBenchValue *lval = &vargs[0];
+				PgBenchValue *rval = &vargs[1];
+
+				Assert(nargs == 2);
+
+				/*
+				 * If both operands are int and exp >= 0 use
+				 * the ipow() function, else use pow()
+				 */
+				if (lval->type == PGBT_INT &&
+					 rval->type == PGBT_INT)
+				{
+
+					int64		li,
+								ri;
+
+					if (!coerceToInt(lval, &li) ||
+						!coerceToInt(rval, &ri))
+						return false;
+
+					if (ri >= 0)
+						setIntValue(retval, ipow(li, ri));
+					else
+						setDoubleValue(retval, pow(li, ri));
+				}
+				else
+				{
+					double		ld,
+								rd;
+
+					if (!coerceToDouble(lval, &ld) ||
+						!coerceToDouble(rval, &rd))
+						return false;
+
+					setDoubleValue(retval, pow(ld, rd));
+				}
+				return true;
+			}
+
 		default:
 			/* cannot get here */
 			Assert(0);
diff --git a/src/bin/pgbench/pgbench.h b/src/bin/pgbench/pgbench.h
index fd428af274..e0132b5fcf 100644
--- a/src/bin/pgbench/pgbench.h
+++ b/src/bin/pgbench/pgbench.h
@@ -75,7 +75,8 @@ typedef enum PgBenchFunction
 	PGBENCH_SQRT,
 	PGBENCH_RANDOM,
 	PGBENCH_RANDOM_GAUSSIAN,
-	PGBENCH_RANDOM_EXPONENTIAL
+	PGBENCH_RANDOM_EXPONENTIAL,
+	PGBENCH_POW
 } PgBenchFunction;
 
 typedef struct PgBenchExpr PgBenchExpr;
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index c095881312..fcb30cdde5 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -231,7 +231,14 @@ pgbench(
 		qr{command=18.: double 18\b},
 		qr{command=19.: double 19\b},
 		qr{command=20.: double 20\b},
-		qr{command=21.: int 9223372036854775807\b}, ],
+		qr{command=21.: int 9223372036854775807\b},
+		qr{command=23.: int -27\b},
+		qr{command=24.: double 1024\b},
+		qr{command=25.: int 1\b},
+		qr{command=26.: double 1\b},
+		qr{command=27.: double -0.125\b},
+		qr{command=28.: double -0.125\b},
+        ],
 	'pgbench expressions',
 	{   '001_pgbench_expressions' => q{-- integer functions
 \set i1 debug(random(1, 100))
@@ -261,6 +268,13 @@ pgbench(
 \set maxint debug(:minint - 1)
 -- reset a variable
 \set i1 0
+--- pow() operator
+\set poweri debug(pow(-3,3))
+\set powerd debug(pow(2.0,10))
+\set poweriz debug(pow(0,0))
+\set powerdz debug(pow(0.0,0.0))
+\set powernegi debug(pow(-2,-3))
+\set powernegd debug(pow(-2.0,-3.0))
 } });
 
 # backslash commands
-- 
2.15.1