Fix non-portable use of round().

anarazel · anarazel · commit 686d399f2be6 · 2018-03-31T20:26:47.000-07:00
round() is from C99. Use rint() instead. There are behavioral differences between round() and rint(), but they should not matter to the Bloom filter optimal_k() function. We already assume POSIX behavior for rint(), so there is no question of rint() not using "rounds towards nearest" as its rounding mode. Cleanup from commit 51bc271. Per buildfarm member thrips. Author: Peter Geoghegan Discussion: https://postgr.es/m/CAH2-Wzn76eCGUonARy-wrVtMHsf+4cvbK_oJAWTLfORTU5ki0w@mail.gmail.com
diff --git a/src/backend/lib/bloomfilter.c b/src/backend/lib/bloomfilter.c
@@ -240,7 +240,7 @@ my_bloom_power(uint64 target_bitset_bits)
 static int
 optimal_k(uint64 bitset_bits, int64 total_elems)
 {
-	int			k = round(log(2.0) * bitset_bits / total_elems);
+	int			k = rint(log(2.0) * bitset_bits / total_elems);
 
 	return Max(1, Min(k, MAX_HASH_FUNCS));
 }

Original file line number	Diff line number	Diff line change
`@@ -240,7 +240,7 @@ my_bloom_power(uint64 target_bitset_bits)`
`240`	`240`	`static int`
`241`	`241`	`optimal_k(uint64 bitset_bits, int64 total_elems)`
`242`	`242`	`{`
`243`		`- int k = round(log(2.0) * bitset_bits / total_elems);`
	`243`	`+ int k = rint(log(2.0) * bitset_bits / total_elems);`
`244`	`244`
`245`	`245`	`return Max(1, Min(k, MAX_HASH_FUNCS));`
`246`	`246`	`}`