postgresql/contrib/btree_gist/btree_ts.c
Tom Lane b2cbced9ee Support timezone abbreviations that sometimes change.
Up to now, PG has assumed that any given timezone abbreviation (such as
"EDT") represents a constant GMT offset in the usage of any particular
region; we had a way to configure what that offset was, but not for it
to be changeable over time.  But, as with most things horological, this
view of the world is too simplistic: there are numerous regions that have
at one time or another switched to a different GMT offset but kept using
the same timezone abbreviation.  Almost the entire Russian Federation did
that a few years ago, and later this month they're going to do it again.
And there are similar examples all over the world.

To cope with this, invent the notion of a "dynamic timezone abbreviation",
which is one that is referenced to a particular underlying timezone
(as defined in the IANA timezone database) and means whatever it currently
means in that zone.  For zones that use or have used daylight-savings time,
the standard and DST abbreviations continue to have the property that you
can specify standard or DST time and get that time offset whether or not
DST was theoretically in effect at the time.  However, the abbreviations
mean what they meant at the time in question (or most recently before that
time) rather than being absolutely fixed.

The standard abbreviation-list files have been changed to use this behavior
for abbreviations that have actually varied in meaning since 1970.  The
old simple-numeric definitions are kept for abbreviations that have not
changed, since they are a bit faster to resolve.

While this is clearly a new feature, it seems necessary to back-patch it
into all active branches, because otherwise use of Russian zone
abbreviations is going to become even more problematic than it already was.
This change supersedes the changes in commit 513d06ded et al to modify the
fixed meanings of the Russian abbreviations; since we've not shipped that
yet, this will avoid an undesirably incompatible (not to mention incorrect)
change in behavior for timestamps between 2011 and 2014.

This patch makes some cosmetic changes in ecpglib to keep its usage of
datetime lookup tables as similar as possible to the backend code, but
doesn't do anything about the increasingly obsolete set of timezone
abbreviation definitions that are hard-wired into ecpglib.  Whatever we
do about that will likely not be appropriate material for back-patching.
Also, a potential free() of a garbage pointer after an out-of-memory
failure in ecpglib has been fixed.

This patch also fixes pre-existing bugs in DetermineTimeZoneOffset() that
caused it to produce unexpected results near a timezone transition, if
both the "before" and "after" states are marked as standard time.  We'd
only ever thought about or tested transitions between standard and DST
time, but that's not what's happening when a zone simply redefines their
base GMT offset.

In passing, update the SGML documentation to refer to the Olson/zoneinfo/
zic timezone database as the "IANA" database, since it's now being
maintained under the auspices of IANA.
2014-10-16 15:22:10 -04:00

405 lines
9.4 KiB
C

/*
* contrib/btree_gist/btree_ts.c
*/
#include "postgres.h"
#include "btree_gist.h"
#include "btree_utils_num.h"
#include "utils/builtins.h"
#include "utils/datetime.h"
typedef struct
{
Timestamp lower;
Timestamp upper;
} tsKEY;
/*
** timestamp ops
*/
PG_FUNCTION_INFO_V1(gbt_ts_compress);
PG_FUNCTION_INFO_V1(gbt_tstz_compress);
PG_FUNCTION_INFO_V1(gbt_ts_union);
PG_FUNCTION_INFO_V1(gbt_ts_picksplit);
PG_FUNCTION_INFO_V1(gbt_ts_consistent);
PG_FUNCTION_INFO_V1(gbt_ts_distance);
PG_FUNCTION_INFO_V1(gbt_tstz_consistent);
PG_FUNCTION_INFO_V1(gbt_tstz_distance);
PG_FUNCTION_INFO_V1(gbt_ts_penalty);
PG_FUNCTION_INFO_V1(gbt_ts_same);
#ifdef USE_FLOAT8_BYVAL
#define TimestampGetDatumFast(X) TimestampGetDatum(X)
#else
#define TimestampGetDatumFast(X) PointerGetDatum(&(X))
#endif
static bool
gbt_tsgt(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
return DatumGetBool(DirectFunctionCall2(timestamp_gt,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
}
static bool
gbt_tsge(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
return DatumGetBool(DirectFunctionCall2(timestamp_ge,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
}
static bool
gbt_tseq(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
return DatumGetBool(DirectFunctionCall2(timestamp_eq,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
}
static bool
gbt_tsle(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
return DatumGetBool(DirectFunctionCall2(timestamp_le,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
}
static bool
gbt_tslt(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
return DatumGetBool(DirectFunctionCall2(timestamp_lt,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
}
static int
gbt_tskey_cmp(const void *a, const void *b)
{
tsKEY *ia = (tsKEY *) (((const Nsrt *) a)->t);
tsKEY *ib = (tsKEY *) (((const Nsrt *) b)->t);
int res;
res = DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->lower), TimestampGetDatumFast(ib->lower)));
if (res == 0)
return DatumGetInt32(DirectFunctionCall2(timestamp_cmp, TimestampGetDatumFast(ia->upper), TimestampGetDatumFast(ib->upper)));
return res;
}
static float8
gbt_ts_dist(const void *a, const void *b)
{
const Timestamp *aa = (const Timestamp *) a;
const Timestamp *bb = (const Timestamp *) b;
Interval *i;
if (TIMESTAMP_NOT_FINITE(*aa) || TIMESTAMP_NOT_FINITE(*bb))
return get_float8_infinity();
i = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
TimestampGetDatumFast(*aa),
TimestampGetDatumFast(*bb)));
return (float8) Abs(INTERVAL_TO_SEC(i));
}
static const gbtree_ninfo tinfo =
{
gbt_t_ts,
sizeof(Timestamp),
16, /* sizeof(gbtreekey16) */
gbt_tsgt,
gbt_tsge,
gbt_tseq,
gbt_tsle,
gbt_tslt,
gbt_tskey_cmp,
gbt_ts_dist
};
PG_FUNCTION_INFO_V1(ts_dist);
Datum
ts_dist(PG_FUNCTION_ARGS)
{
Timestamp a = PG_GETARG_TIMESTAMP(0);
Timestamp b = PG_GETARG_TIMESTAMP(1);
Interval *r;
if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
{
Interval *p = palloc(sizeof(Interval));
p->day = INT_MAX;
p->month = INT_MAX;
#ifdef HAVE_INT64_TIMESTAMP
p->time = INT64CONST(0x7FFFFFFFFFFFFFFF);
#else
p->time = DBL_MAX;
#endif
PG_RETURN_INTERVAL_P(p);
}
else
r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_INTERVAL_P(abs_interval(r));
}
PG_FUNCTION_INFO_V1(tstz_dist);
Datum
tstz_dist(PG_FUNCTION_ARGS)
{
TimestampTz a = PG_GETARG_TIMESTAMPTZ(0);
TimestampTz b = PG_GETARG_TIMESTAMPTZ(1);
Interval *r;
if (TIMESTAMP_NOT_FINITE(a) || TIMESTAMP_NOT_FINITE(b))
{
Interval *p = palloc(sizeof(Interval));
p->day = INT_MAX;
p->month = INT_MAX;
#ifdef HAVE_INT64_TIMESTAMP
p->time = INT64CONST(0x7FFFFFFFFFFFFFFF);
#else
p->time = DBL_MAX;
#endif
PG_RETURN_INTERVAL_P(p);
}
r = DatumGetIntervalP(DirectFunctionCall2(timestamp_mi,
PG_GETARG_DATUM(0),
PG_GETARG_DATUM(1)));
PG_RETURN_INTERVAL_P(abs_interval(r));
}
/**************************************************
* timestamp ops
**************************************************/
static inline Timestamp
tstz_to_ts_gmt(TimestampTz ts)
{
/* No timezone correction is needed, since GMT is offset 0 by definition */
return (Timestamp) ts;
}
Datum
gbt_ts_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval = NULL;
PG_RETURN_POINTER(gbt_num_compress(retval, entry, &tinfo));
}
Datum
gbt_tstz_compress(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
GISTENTRY *retval;
if (entry->leafkey)
{
tsKEY *r = (tsKEY *) palloc(sizeof(tsKEY));
TimestampTz ts = DatumGetTimestampTz(entry->key);
Timestamp gmt;
gmt = tstz_to_ts_gmt(ts);
retval = palloc(sizeof(GISTENTRY));
r->lower = r->upper = gmt;
gistentryinit(*retval, PointerGetDatum(r),
entry->rel, entry->page,
entry->offset, FALSE);
}
else
retval = entry;
PG_RETURN_POINTER(retval);
}
Datum
gbt_ts_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
Timestamp query = PG_GETARG_TIMESTAMP(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
tsKEY *kkk = (tsKEY *) DatumGetPointer(entry->key);
GBT_NUMKEY_R key;
/* All cases served by this function are exact */
*recheck = false;
key.lower = (GBT_NUMKEY *) &kkk->lower;
key.upper = (GBT_NUMKEY *) &kkk->upper;
PG_RETURN_BOOL(
gbt_num_consistent(&key, (void *) &query, &strategy, GIST_LEAF(entry), &tinfo)
);
}
Datum
gbt_ts_distance(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
Timestamp query = PG_GETARG_TIMESTAMP(1);
/* Oid subtype = PG_GETARG_OID(3); */
tsKEY *kkk = (tsKEY *) DatumGetPointer(entry->key);
GBT_NUMKEY_R key;
key.lower = (GBT_NUMKEY *) &kkk->lower;
key.upper = (GBT_NUMKEY *) &kkk->upper;
PG_RETURN_FLOAT8(
gbt_num_distance(&key, (void *) &query, GIST_LEAF(entry), &tinfo)
);
}
Datum
gbt_tstz_consistent(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);
StrategyNumber strategy = (StrategyNumber) PG_GETARG_UINT16(2);
/* Oid subtype = PG_GETARG_OID(3); */
bool *recheck = (bool *) PG_GETARG_POINTER(4);
char *kkk = (char *) DatumGetPointer(entry->key);
GBT_NUMKEY_R key;
Timestamp qqq;
/* All cases served by this function are exact */
*recheck = false;
key.lower = (GBT_NUMKEY *) &kkk[0];
key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
qqq = tstz_to_ts_gmt(query);
PG_RETURN_BOOL(
gbt_num_consistent(&key, (void *) &qqq, &strategy, GIST_LEAF(entry), &tinfo)
);
}
Datum
gbt_tstz_distance(PG_FUNCTION_ARGS)
{
GISTENTRY *entry = (GISTENTRY *) PG_GETARG_POINTER(0);
TimestampTz query = PG_GETARG_TIMESTAMPTZ(1);
/* Oid subtype = PG_GETARG_OID(3); */
char *kkk = (char *) DatumGetPointer(entry->key);
GBT_NUMKEY_R key;
Timestamp qqq;
key.lower = (GBT_NUMKEY *) &kkk[0];
key.upper = (GBT_NUMKEY *) &kkk[MAXALIGN(tinfo.size)];
qqq = tstz_to_ts_gmt(query);
PG_RETURN_FLOAT8(
gbt_num_distance(&key, (void *) &qqq, GIST_LEAF(entry), &tinfo)
);
}
Datum
gbt_ts_union(PG_FUNCTION_ARGS)
{
GistEntryVector *entryvec = (GistEntryVector *) PG_GETARG_POINTER(0);
void *out = palloc(sizeof(tsKEY));
*(int *) PG_GETARG_POINTER(1) = sizeof(tsKEY);
PG_RETURN_POINTER(gbt_num_union((void *) out, entryvec, &tinfo));
}
#define penalty_check_max_float(val) do { \
if ( val > FLT_MAX ) \
val = FLT_MAX; \
if ( val < -FLT_MAX ) \
val = -FLT_MAX; \
} while(false);
Datum
gbt_ts_penalty(PG_FUNCTION_ARGS)
{
tsKEY *origentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(0))->key);
tsKEY *newentry = (tsKEY *) DatumGetPointer(((GISTENTRY *) PG_GETARG_POINTER(1))->key);
float *result = (float *) PG_GETARG_POINTER(2);
double orgdbl[2],
newdbl[2];
/*
* We are allways using "double" timestamps here. Precision should be good
* enough.
*/
orgdbl[0] = ((double) origentry->lower);
orgdbl[1] = ((double) origentry->upper);
newdbl[0] = ((double) newentry->lower);
newdbl[1] = ((double) newentry->upper);
penalty_check_max_float(orgdbl[0]);
penalty_check_max_float(orgdbl[1]);
penalty_check_max_float(newdbl[0]);
penalty_check_max_float(newdbl[1]);
penalty_num(result, orgdbl[0], orgdbl[1], newdbl[0], newdbl[1]);
PG_RETURN_POINTER(result);
}
Datum
gbt_ts_picksplit(PG_FUNCTION_ARGS)
{
PG_RETURN_POINTER(gbt_num_picksplit(
(GistEntryVector *) PG_GETARG_POINTER(0),
(GIST_SPLITVEC *) PG_GETARG_POINTER(1),
&tinfo
));
}
Datum
gbt_ts_same(PG_FUNCTION_ARGS)
{
tsKEY *b1 = (tsKEY *) PG_GETARG_POINTER(0);
tsKEY *b2 = (tsKEY *) PG_GETARG_POINTER(1);
bool *result = (bool *) PG_GETARG_POINTER(2);
*result = gbt_num_same((void *) b1, (void *) b2, &tinfo);
PG_RETURN_POINTER(result);
}