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-rw-r--r--src/backend/utils/adt/timestamp.c50
-rw-r--r--src/include/common/int128.h276
-rw-r--r--src/test/regress/expected/interval.out64
-rw-r--r--src/test/regress/sql/interval.sql27
-rw-r--r--src/tools/testint128.c183
5 files changed, 590 insertions, 10 deletions
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 4be1999119c..3f6e0d4497b 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -24,6 +24,7 @@
#include "access/hash.h"
#include "access/xact.h"
#include "catalog/pg_type.h"
+#include "common/int128.h"
#include "funcapi.h"
#include "libpq/pqformat.h"
#include "miscadmin.h"
@@ -2288,15 +2289,35 @@ timestamptz_cmp_timestamp(PG_FUNCTION_ARGS)
/*
* interval_relop - is interval1 relop interval2
+ *
+ * Interval comparison is based on converting interval values to a linear
+ * representation expressed in the units of the time field (microseconds,
+ * in the case of integer timestamps) with days assumed to be always 24 hours
+ * and months assumed to be always 30 days. To avoid overflow, we need a
+ * wider-than-int64 datatype for the linear representation, so use INT128.
*/
-static inline TimeOffset
+
+static inline INT128
interval_cmp_value(const Interval *interval)
{
- TimeOffset span;
+ INT128 span;
+ int64 dayfraction;
+ int64 days;
+
+ /*
+ * Separate time field into days and dayfraction, then add the month and
+ * day fields to the days part. We cannot overflow int64 days here.
+ */
+ dayfraction = interval->time % USECS_PER_DAY;
+ days = interval->time / USECS_PER_DAY;
+ days += interval->month * INT64CONST(30);
+ days += interval->day;
- span = interval->time;
- span += interval->month * INT64CONST(30) * USECS_PER_DAY;
- span += interval->day * INT64CONST(24) * USECS_PER_HOUR;
+ /* Widen dayfraction to 128 bits */
+ span = int64_to_int128(dayfraction);
+
+ /* Scale up days to microseconds, forming a 128-bit product */
+ int128_add_int64_mul_int64(&span, days, USECS_PER_DAY);
return span;
}
@@ -2304,10 +2325,10 @@ interval_cmp_value(const Interval *interval)
static int
interval_cmp_internal(Interval *interval1, Interval *interval2)
{
- TimeOffset span1 = interval_cmp_value(interval1);
- TimeOffset span2 = interval_cmp_value(interval2);
+ INT128 span1 = interval_cmp_value(interval1);
+ INT128 span2 = interval_cmp_value(interval2);
- return ((span1 < span2) ? -1 : (span1 > span2) ? 1 : 0);
+ return int128_compare(span1, span2);
}
Datum
@@ -2384,9 +2405,18 @@ Datum
interval_hash(PG_FUNCTION_ARGS)
{
Interval *interval = PG_GETARG_INTERVAL_P(0);
- TimeOffset span = interval_cmp_value(interval);
+ INT128 span = interval_cmp_value(interval);
+ int64 span64;
+
+ /*
+ * Use only the least significant 64 bits for hashing. The upper 64 bits
+ * seldom add any useful information, and besides we must do it like this
+ * for compatibility with hashes calculated before use of INT128 was
+ * introduced.
+ */
+ span64 = int128_to_int64(span);
- return DirectFunctionCall1(hashint8, Int64GetDatumFast(span));
+ return DirectFunctionCall1(hashint8, Int64GetDatumFast(span64));
}
/* overlaps_timestamp() --- implements the SQL OVERLAPS operator.
diff --git a/src/include/common/int128.h b/src/include/common/int128.h
new file mode 100644
index 00000000000..4c46e26f400
--- /dev/null
+++ b/src/include/common/int128.h
@@ -0,0 +1,276 @@
+/*-------------------------------------------------------------------------
+ *
+ * int128.h
+ * Roll-our-own 128-bit integer arithmetic.
+ *
+ * We make use of the native int128 type if there is one, otherwise
+ * implement things the hard way based on two int64 halves.
+ *
+ * See src/tools/testint128.c for a simple test harness for this file.
+ *
+ * Copyright (c) 2017, PostgreSQL Global Development Group
+ *
+ * src/include/common/int128.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef INT128_H
+#define INT128_H
+
+/*
+ * For testing purposes, use of native int128 can be switched on/off by
+ * predefining USE_NATIVE_INT128.
+ */
+#ifndef USE_NATIVE_INT128
+#ifdef HAVE_INT128
+#define USE_NATIVE_INT128 1
+#else
+#define USE_NATIVE_INT128 0
+#endif
+#endif
+
+
+#if USE_NATIVE_INT128
+
+typedef int128 INT128;
+
+/*
+ * Add an unsigned int64 value into an INT128 variable.
+ */
+static inline void
+int128_add_uint64(INT128 *i128, uint64 v)
+{
+ *i128 += v;
+}
+
+/*
+ * Add a signed int64 value into an INT128 variable.
+ */
+static inline void
+int128_add_int64(INT128 *i128, int64 v)
+{
+ *i128 += v;
+}
+
+/*
+ * Add the 128-bit product of two int64 values into an INT128 variable.
+ *
+ * XXX with a stupid compiler, this could actually be less efficient than
+ * the other implementation; maybe we should do it by hand always?
+ */
+static inline void
+int128_add_int64_mul_int64(INT128 *i128, int64 x, int64 y)
+{
+ *i128 += (int128) x *(int128) y;
+}
+
+/*
+ * Compare two INT128 values, return -1, 0, or +1.
+ */
+static inline int
+int128_compare(INT128 x, INT128 y)
+{
+ if (x < y)
+ return -1;
+ if (x > y)
+ return 1;
+ return 0;
+}
+
+/*
+ * Widen int64 to INT128.
+ */
+static inline INT128
+int64_to_int128(int64 v)
+{
+ return (INT128) v;
+}
+
+/*
+ * Convert INT128 to int64 (losing any high-order bits).
+ * This also works fine for casting down to uint64.
+ */
+static inline int64
+int128_to_int64(INT128 val)
+{
+ return (int64) val;
+}
+
+#else /* !USE_NATIVE_INT128 */
+
+/*
+ * We lay out the INT128 structure with the same content and byte ordering
+ * that a native int128 type would (probably) have. This makes no difference
+ * for ordinary use of INT128, but allows union'ing INT128 with int128 for
+ * testing purposes.
+ */
+typedef struct
+{
+#ifdef WORDS_BIGENDIAN
+ int64 hi; /* most significant 64 bits, including sign */
+ uint64 lo; /* least significant 64 bits, without sign */
+#else
+ uint64 lo; /* least significant 64 bits, without sign */
+ int64 hi; /* most significant 64 bits, including sign */
+#endif
+} INT128;
+
+/*
+ * Add an unsigned int64 value into an INT128 variable.
+ */
+static inline void
+int128_add_uint64(INT128 *i128, uint64 v)
+{
+ /*
+ * First add the value to the .lo part, then check to see if a carry needs
+ * to be propagated into the .hi part. A carry is needed if both inputs
+ * have high bits set, or if just one input has high bit set while the new
+ * .lo part doesn't. Remember that .lo part is unsigned; we cast to
+ * signed here just as a cheap way to check the high bit.
+ */
+ uint64 oldlo = i128->lo;
+
+ i128->lo += v;
+ if (((int64) v < 0 && (int64) oldlo < 0) ||
+ (((int64) v < 0 || (int64) oldlo < 0) && (int64) i128->lo >= 0))
+ i128->hi++;
+}
+
+/*
+ * Add a signed int64 value into an INT128 variable.
+ */
+static inline void
+int128_add_int64(INT128 *i128, int64 v)
+{
+ /*
+ * This is much like the above except that the carry logic differs for
+ * negative v. Ordinarily we'd need to subtract 1 from the .hi part
+ * (corresponding to adding the sign-extended bits of v to it); but if
+ * there is a carry out of the .lo part, that cancels and we do nothing.
+ */
+ uint64 oldlo = i128->lo;
+
+ i128->lo += v;
+ if (v >= 0)
+ {
+ if ((int64) oldlo < 0 && (int64) i128->lo >= 0)
+ i128->hi++;
+ }
+ else
+ {
+ if (!((int64) oldlo < 0 || (int64) i128->lo >= 0))
+ i128->hi--;
+ }
+}
+
+/*
+ * INT64_AU32 extracts the most significant 32 bits of int64 as int64, while
+ * INT64_AL32 extracts the least significant 32 bits as uint64.
+ */
+#define INT64_AU32(i64) ((i64) >> 32)
+#define INT64_AL32(i64) ((i64) & UINT64CONST(0xFFFFFFFF))
+
+/*
+ * Add the 128-bit product of two int64 values into an INT128 variable.
+ */
+static inline void
+int128_add_int64_mul_int64(INT128 *i128, int64 x, int64 y)
+{
+ /* INT64_AU32 must use arithmetic right shift */
+ StaticAssertStmt(((int64) -1 >> 1) == (int64) -1,
+ "arithmetic right shift is needed");
+
+ /*----------
+ * Form the 128-bit product x * y using 64-bit arithmetic.
+ * Considering each 64-bit input as having 32-bit high and low parts,
+ * we can compute
+ *
+ * x * y = ((x.hi << 32) + x.lo) * (((y.hi << 32) + y.lo)
+ * = (x.hi * y.hi) << 64 +
+ * (x.hi * y.lo) << 32 +
+ * (x.lo * y.hi) << 32 +
+ * x.lo * y.lo
+ *
+ * Each individual product is of 32-bit terms so it won't overflow when
+ * computed in 64-bit arithmetic. Then we just have to shift it to the
+ * correct position while adding into the 128-bit result. We must also
+ * keep in mind that the "lo" parts must be treated as unsigned.
+ *----------
+ */
+
+ /* No need to work hard if product must be zero */
+ if (x != 0 && y != 0)
+ {
+ int64 x_u32 = INT64_AU32(x);
+ uint64 x_l32 = INT64_AL32(x);
+ int64 y_u32 = INT64_AU32(y);
+ uint64 y_l32 = INT64_AL32(y);
+ int64 tmp;
+
+ /* the first term */
+ i128->hi += x_u32 * y_u32;
+
+ /* the second term: sign-extend it only if x is negative */
+ tmp = x_u32 * y_l32;
+ if (x < 0)
+ i128->hi += INT64_AU32(tmp);
+ else
+ i128->hi += ((uint64) tmp) >> 32;
+ int128_add_uint64(i128, ((uint64) INT64_AL32(tmp)) << 32);
+
+ /* the third term: sign-extend it only if y is negative */
+ tmp = x_l32 * y_u32;
+ if (y < 0)
+ i128->hi += INT64_AU32(tmp);
+ else
+ i128->hi += ((uint64) tmp) >> 32;
+ int128_add_uint64(i128, ((uint64) INT64_AL32(tmp)) << 32);
+
+ /* the fourth term: always unsigned */
+ int128_add_uint64(i128, x_l32 * y_l32);
+ }
+}
+
+/*
+ * Compare two INT128 values, return -1, 0, or +1.
+ */
+static inline int
+int128_compare(INT128 x, INT128 y)
+{
+ if (x.hi < y.hi)
+ return -1;
+ if (x.hi > y.hi)
+ return 1;
+ if (x.lo < y.lo)
+ return -1;
+ if (x.lo > y.lo)
+ return 1;
+ return 0;
+}
+
+/*
+ * Widen int64 to INT128.
+ */
+static inline INT128
+int64_to_int128(int64 v)
+{
+ INT128 val;
+
+ val.lo = (uint64) v;
+ val.hi = (v < 0) ? -INT64CONST(1) : INT64CONST(0);
+ return val;
+}
+
+/*
+ * Convert INT128 to int64 (losing any high-order bits).
+ * This also works fine for casting down to uint64.
+ */
+static inline int64
+int128_to_int64(INT128 val)
+{
+ return (int64) val.lo;
+}
+
+#endif /* USE_NATIVE_INT128 */
+
+#endif /* INT128_H */
diff --git a/src/test/regress/expected/interval.out b/src/test/regress/expected/interval.out
index 946c97ad924..f88f34550ad 100644
--- a/src/test/regress/expected/interval.out
+++ b/src/test/regress/expected/interval.out
@@ -207,6 +207,70 @@ SELECT '' AS fortyfive, r1.*, r2.*
| 34 years | 6 years
(45 rows)
+-- Test intervals that are large enough to overflow 64 bits in comparisons
+CREATE TEMP TABLE INTERVAL_TBL_OF (f1 interval);
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES
+ ('2147483647 days 2147483647 months'),
+ ('2147483647 days -2147483648 months'),
+ ('1 year'),
+ ('-2147483648 days 2147483647 months'),
+ ('-2147483648 days -2147483648 months');
+-- these should fail as out-of-range
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483648 days');
+ERROR: interval field value out of range: "2147483648 days"
+LINE 1: INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483648 days');
+ ^
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483649 days');
+ERROR: interval field value out of range: "-2147483649 days"
+LINE 1: INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483649 days')...
+ ^
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483647 years');
+ERROR: interval out of range
+LINE 1: INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483647 years')...
+ ^
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483648 years');
+ERROR: interval out of range
+LINE 1: INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483648 years'...
+ ^
+SELECT r1.*, r2.*
+ FROM INTERVAL_TBL_OF r1, INTERVAL_TBL_OF r2
+ WHERE r1.f1 > r2.f1
+ ORDER BY r1.f1, r2.f1;
+ f1 | f1
+-------------------------------------------+-------------------------------------------
+ -178956970 years -8 mons +2147483647 days | -178956970 years -8 mons -2147483648 days
+ 1 year | -178956970 years -8 mons -2147483648 days
+ 1 year | -178956970 years -8 mons +2147483647 days
+ 178956970 years 7 mons -2147483648 days | -178956970 years -8 mons -2147483648 days
+ 178956970 years 7 mons -2147483648 days | -178956970 years -8 mons +2147483647 days
+ 178956970 years 7 mons -2147483648 days | 1 year
+ 178956970 years 7 mons 2147483647 days | -178956970 years -8 mons -2147483648 days
+ 178956970 years 7 mons 2147483647 days | -178956970 years -8 mons +2147483647 days
+ 178956970 years 7 mons 2147483647 days | 1 year
+ 178956970 years 7 mons 2147483647 days | 178956970 years 7 mons -2147483648 days
+(10 rows)
+
+CREATE INDEX ON INTERVAL_TBL_OF USING btree (f1);
+SET enable_seqscan TO false;
+EXPLAIN (COSTS OFF)
+SELECT f1 FROM INTERVAL_TBL_OF r1 ORDER BY f1;
+ QUERY PLAN
+--------------------------------------------------------------------
+ Index Only Scan using interval_tbl_of_f1_idx on interval_tbl_of r1
+(1 row)
+
+SELECT f1 FROM INTERVAL_TBL_OF r1 ORDER BY f1;
+ f1
+-------------------------------------------
+ -178956970 years -8 mons -2147483648 days
+ -178956970 years -8 mons +2147483647 days
+ 1 year
+ 178956970 years 7 mons -2147483648 days
+ 178956970 years 7 mons 2147483647 days
+(5 rows)
+
+RESET enable_seqscan;
+DROP TABLE INTERVAL_TBL_OF;
-- Test multiplication and division with intervals.
-- Floating point arithmetic rounding errors can lead to unexpected results,
-- though the code attempts to do the right thing and round up to days and
diff --git a/src/test/regress/sql/interval.sql b/src/test/regress/sql/interval.sql
index cff9adab321..bc5537d1b9c 100644
--- a/src/test/regress/sql/interval.sql
+++ b/src/test/regress/sql/interval.sql
@@ -59,6 +59,33 @@ SELECT '' AS fortyfive, r1.*, r2.*
WHERE r1.f1 > r2.f1
ORDER BY r1.f1, r2.f1;
+-- Test intervals that are large enough to overflow 64 bits in comparisons
+CREATE TEMP TABLE INTERVAL_TBL_OF (f1 interval);
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES
+ ('2147483647 days 2147483647 months'),
+ ('2147483647 days -2147483648 months'),
+ ('1 year'),
+ ('-2147483648 days 2147483647 months'),
+ ('-2147483648 days -2147483648 months');
+-- these should fail as out-of-range
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483648 days');
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483649 days');
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('2147483647 years');
+INSERT INTO INTERVAL_TBL_OF (f1) VALUES ('-2147483648 years');
+
+SELECT r1.*, r2.*
+ FROM INTERVAL_TBL_OF r1, INTERVAL_TBL_OF r2
+ WHERE r1.f1 > r2.f1
+ ORDER BY r1.f1, r2.f1;
+
+CREATE INDEX ON INTERVAL_TBL_OF USING btree (f1);
+SET enable_seqscan TO false;
+EXPLAIN (COSTS OFF)
+SELECT f1 FROM INTERVAL_TBL_OF r1 ORDER BY f1;
+SELECT f1 FROM INTERVAL_TBL_OF r1 ORDER BY f1;
+RESET enable_seqscan;
+
+DROP TABLE INTERVAL_TBL_OF;
-- Test multiplication and division with intervals.
-- Floating point arithmetic rounding errors can lead to unexpected results,
diff --git a/src/tools/testint128.c b/src/tools/testint128.c
new file mode 100644
index 00000000000..f57806367cc
--- /dev/null
+++ b/src/tools/testint128.c
@@ -0,0 +1,183 @@
+/*-------------------------------------------------------------------------
+ *
+ * testint128.c
+ * Testbed for roll-our-own 128-bit integer arithmetic.
+ *
+ * This is a standalone test program that compares the behavior of an
+ * implementation in int128.h to an (assumed correct) int128 native type.
+ *
+ * Copyright (c) 2017, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ * src/tools/testint128.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "postgres_fe.h"
+
+/*
+ * By default, we test the non-native implementation in int128.h; but
+ * by predefining USE_NATIVE_INT128 to 1, you can test the native
+ * implementation, just to be sure.
+ */
+#ifndef USE_NATIVE_INT128
+#define USE_NATIVE_INT128 0
+#endif
+
+#include "common/int128.h"
+
+/*
+ * We assume the parts of this union are laid out compatibly.
+ */
+typedef union
+{
+ int128 i128;
+ INT128 I128;
+ union
+ {
+#ifdef WORDS_BIGENDIAN
+ int64 hi;
+ uint64 lo;
+#else
+ uint64 lo;
+ int64 hi;
+#endif
+ } hl;
+} test128;
+
+
+/*
+ * Control version of comparator.
+ */
+static inline int
+my_int128_compare(int128 x, int128 y)
+{
+ if (x < y)
+ return -1;
+ if (x > y)
+ return 1;
+ return 0;
+}
+
+/*
+ * Get a random uint64 value.
+ * We don't assume random() is good for more than 16 bits.
+ */
+static uint64
+get_random_uint64(void)
+{
+ uint64 x;
+
+ x = (uint64) (random() & 0xFFFF) << 48;
+ x |= (uint64) (random() & 0xFFFF) << 32;
+ x |= (uint64) (random() & 0xFFFF) << 16;
+ x |= (uint64) (random() & 0xFFFF);
+ return x;
+}
+
+/*
+ * Main program.
+ *
+ * Generates a lot of random numbers and tests the implementation for each.
+ * The results should be reproducible, since we don't call srandom().
+ *
+ * You can give a loop count if you don't like the default 1B iterations.
+ */
+int
+main(int argc, char **argv)
+{
+ long count;
+
+ if (argc >= 2)
+ count = strtol(argv[1], NULL, 0);
+ else
+ count = 1000000000;
+
+ while (count-- > 0)
+ {
+ int64 x = get_random_uint64();
+ int64 y = get_random_uint64();
+ int64 z = get_random_uint64();
+ test128 t1;
+ test128 t2;
+
+ /* check unsigned addition */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2 = t1;
+ t1.i128 += (int128) (uint64) z;
+ int128_add_uint64(&t2.I128, (uint64) z);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%016lX%016lX + unsigned %lX\n", x, y, z);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check signed addition */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2 = t1;
+ t1.i128 += (int128) z;
+ int128_add_int64(&t2.I128, z);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%016lX%016lX + signed %lX\n", x, y, z);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check multiplication */
+ t1.i128 = (int128) x *(int128) y;
+
+ t2.hl.hi = t2.hl.lo = 0;
+ int128_add_int64_mul_int64(&t2.I128, x, y);
+
+ if (t1.hl.hi != t2.hl.hi || t1.hl.lo != t2.hl.lo)
+ {
+ printf("%lX * %lX\n", x, y);
+ printf("native = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("result = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check comparison */
+ t1.hl.hi = x;
+ t1.hl.lo = y;
+ t2.hl.hi = z;
+ t2.hl.lo = get_random_uint64();
+
+ if (my_int128_compare(t1.i128, t2.i128) !=
+ int128_compare(t1.I128, t2.I128))
+ {
+ printf("comparison failure: %d vs %d\n",
+ my_int128_compare(t1.i128, t2.i128),
+ int128_compare(t1.I128, t2.I128));
+ printf("arg1 = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("arg2 = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+
+ /* check case with identical hi parts; above will hardly ever hit it */
+ t2.hl.hi = x;
+
+ if (my_int128_compare(t1.i128, t2.i128) !=
+ int128_compare(t1.I128, t2.I128))
+ {
+ printf("comparison failure: %d vs %d\n",
+ my_int128_compare(t1.i128, t2.i128),
+ int128_compare(t1.I128, t2.I128));
+ printf("arg1 = %016lX%016lX\n", t1.hl.hi, t1.hl.lo);
+ printf("arg2 = %016lX%016lX\n", t2.hl.hi, t2.hl.lo);
+ return 1;
+ }
+ }
+
+ return 0;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-25 10:13:09 +0000