Fix interval_transform so it doesn't throw away non-no-op casts.
interval_transform() contained two separate bugs that caused it to sometimes mistakenly decide that a cast from interval to restricted interval is a no-op and throw it away. First, it was wrong to rely on dt.h's field type macros to have an ordering consistent with the field's significance; in one case they do not. This led to mistakenly treating YEAR as less significant than MONTH, so that a cast from INTERVAL MONTH to INTERVAL YEAR was incorrectly discarded. Second, fls(1<<k) produces k+1 not k, so comparing its output directly to SECOND was wrong. This led to supposing that a cast to INTERVAL MINUTE was really a cast to INTERVAL SECOND and so could be discarded. To fix, get rid of the use of fls(), and make a function based on intervaltypmodout to produce a field ID code adapted to the need here. Per bug #14479 from Piotr Stefaniak. Back-patch to 9.2 where transform functions were introduced, because this code was born broken. Discussion: https://postgr.es/m/20161227172307.10135.7747@wrigleys.postgresql.org
This commit is contained in:
Tom Lane
parent
71f996d221
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@ -1250,6 +1250,59 @@ intervaltypmodout(PG_FUNCTION_ARGS)
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PG_RETURN_CSTRING(res);
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}
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/*
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* Given an interval typmod value, return a code for the least-significant
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* field that the typmod allows to be nonzero, for instance given
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* INTERVAL DAY TO HOUR we want to identify "hour".
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*
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* The results should be ordered by field significance, which means
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* we can't use the dt.h macros YEAR etc, because for some odd reason
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* they aren't ordered that way. Instead, arbitrarily represent
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* SECOND = 0, MINUTE = 1, HOUR = 2, DAY = 3, MONTH = 4, YEAR = 5.
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*/
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static int
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intervaltypmodleastfield(int32 typmod)
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{
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if (typmod < 0)
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return 0; /* SECOND */
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switch (INTERVAL_RANGE(typmod))
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{
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case INTERVAL_MASK(YEAR):
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return 5; /* YEAR */
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case INTERVAL_MASK(MONTH):
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return 4; /* MONTH */
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case INTERVAL_MASK(DAY):
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return 3; /* DAY */
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case INTERVAL_MASK(HOUR):
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return 2; /* HOUR */
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case INTERVAL_MASK(MINUTE):
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return 1; /* MINUTE */
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case INTERVAL_MASK(SECOND):
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return 0; /* SECOND */
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case INTERVAL_MASK(YEAR) | INTERVAL_MASK(MONTH):
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return 4; /* MONTH */
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case INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR):
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return 2; /* HOUR */
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case INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE):
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return 1; /* MINUTE */
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case INTERVAL_MASK(DAY) | INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE) | INTERVAL_MASK(SECOND):
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return 0; /* SECOND */
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case INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE):
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return 1; /* MINUTE */
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case INTERVAL_MASK(HOUR) | INTERVAL_MASK(MINUTE) | INTERVAL_MASK(SECOND):
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return 0; /* SECOND */
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case INTERVAL_MASK(MINUTE) | INTERVAL_MASK(SECOND):
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return 0; /* SECOND */
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case INTERVAL_FULL_RANGE:
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return 0; /* SECOND */
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default:
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elog(ERROR, "invalid INTERVAL typmod: 0x%x", typmod);
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break;
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}
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return 0; /* can't get here, but keep compiler quiet */
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}
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/* interval_transform()
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* Flatten superfluous calls to interval_scale(). The interval typmod is
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@ -1271,39 +1324,39 @@ interval_transform(PG_FUNCTION_ARGS)
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if (IsA(typmod, Const) &&!((Const *) typmod)->constisnull)
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{
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Node *source = (Node *) linitial(expr->args);
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int32 old_typmod = exprTypmod(source);
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int32 new_typmod = DatumGetInt32(((Const *) typmod)->constvalue);
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int old_range;
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int old_precis;
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int new_range = INTERVAL_RANGE(new_typmod);
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int new_precis = INTERVAL_PRECISION(new_typmod);
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int new_range_fls;
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int old_range_fls;
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bool noop;
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if (old_typmod < 0)
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{
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old_range = INTERVAL_FULL_RANGE;
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old_precis = INTERVAL_FULL_PRECISION;
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}
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if (new_typmod < 0)
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noop = true;
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else
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{
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old_range = INTERVAL_RANGE(old_typmod);
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old_precis = INTERVAL_PRECISION(old_typmod);
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}
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int32 old_typmod = exprTypmod(source);
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int old_least_field;
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int new_least_field;
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int old_precis;
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int new_precis;
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/*
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* Temporally-smaller fields occupy higher positions in the range
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* bitmap. Since only the temporally-smallest bit matters for length
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* coercion purposes, we compare the last-set bits in the ranges.
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* Precision, which is to say, sub-second precision, only affects
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* ranges that include SECOND.
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*/
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new_range_fls = fls(new_range);
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old_range_fls = fls(old_range);
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if (new_typmod < 0 ||
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((new_range_fls >= SECOND || new_range_fls >= old_range_fls) &&
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(old_range_fls < SECOND || new_precis >= MAX_INTERVAL_PRECISION ||
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new_precis >= old_precis)))
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old_least_field = intervaltypmodleastfield(old_typmod);
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new_least_field = intervaltypmodleastfield(new_typmod);
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if (old_typmod < 0)
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old_precis = INTERVAL_FULL_PRECISION;
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else
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old_precis = INTERVAL_PRECISION(old_typmod);
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new_precis = INTERVAL_PRECISION(new_typmod);
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/*
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* Cast is a no-op if least field stays the same or decreases
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* while precision stays the same or increases. But precision,
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* which is to say, sub-second precision, only affects ranges that
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* include SECOND.
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*/
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noop = (new_least_field <= old_least_field) &&
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(old_least_field > 0 /* SECOND */ ||
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new_precis >= MAX_INTERVAL_PRECISION ||
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new_precis >= old_precis);
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}
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if (noop)
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ret = relabel_to_typmod(source, new_typmod);
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}
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@ -682,6 +682,24 @@ SELECT interval '1 2:03:04.5678' minute to second(2);
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1 day 02:03:04.57
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(1 row)
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-- test casting to restricted precision (bug #14479)
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SELECT f1, f1::INTERVAL DAY TO MINUTE AS "minutes",
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(f1 + INTERVAL '1 month')::INTERVAL MONTH::INTERVAL YEAR AS "years"
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FROM interval_tbl;
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f1 | minutes | years
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-----------------+-----------------+----------
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00:01:00 | 00:01:00 | 00:00:00
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05:00:00 | 05:00:00 | 00:00:00
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10 days | 10 days | 00:00:00
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34 years | 34 years | 34 years
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3 mons | 3 mons | 00:00:00
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-00:00:14 | 00:00:00 | 00:00:00
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1 day 02:03:04 | 1 day 02:03:00 | 00:00:00
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6 years | 6 years | 6 years
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5 mons | 5 mons | 00:00:00
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5 mons 12:00:00 | 5 mons 12:00:00 | 00:00:00
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(10 rows)
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-- test inputting and outputting SQL standard interval literals
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SET IntervalStyle TO sql_standard;
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SELECT interval '0' AS "zero",
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@ -196,6 +196,11 @@ SELECT interval '1 2.3456' minute to second(2);
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SELECT interval '1 2:03.5678' minute to second(2);
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SELECT interval '1 2:03:04.5678' minute to second(2);
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-- test casting to restricted precision (bug #14479)
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SELECT f1, f1::INTERVAL DAY TO MINUTE AS "minutes",
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(f1 + INTERVAL '1 month')::INTERVAL MONTH::INTERVAL YEAR AS "years"
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FROM interval_tbl;
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-- test inputting and outputting SQL standard interval literals
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SET IntervalStyle TO sql_standard;
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SELECT interval '0' AS "zero",
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