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Commitb181a91

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More fixes for abbreviated keys infrastructure.
First, when LC_COLLATE = C, bttext_abbrev_convert should use memcpy()rather than strxfrm() to construct the abbreviated key, because theauthoritative comparator uses memcpy(). If we do anything else here,we might get inconsistent answers, and the buildfarm says this riskis not theoretical. It should be faster this way, too.Second, while I'm looking at bttext_abbrev_convert, convert a needlessuse of goto into the loop it's trying to implement into an actualloop.Both of the above problems date to the original commit of abbreviatedkeys, commit4ea51cd.Third, fix a bogus assignment to tss->locale before tss is set up.That's a new goof in commitb529b65.
1 parentb529b65 commitb181a91

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+52
-35
lines changed

1 file changed

+52
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‎src/backend/utils/adt/varlena.c

Lines changed: 52 additions & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -63,6 +63,7 @@ typedef struct
6363
char*buf2;/* 2nd string, or abbreviation strxfrm() buf */
6464
intbuflen1;
6565
intbuflen2;
66+
boolcollate_c;
6667
hyperLogLogStateabbr_card;/* Abbreviated key cardinality state */
6768
hyperLogLogStatefull_card;/* Full key cardinality state */
6869
#ifdefHAVE_LOCALE_T
@@ -1744,7 +1745,7 @@ static void
17441745
btsortsupport_worker(SortSupportssup,Oidcollid)
17451746
{
17461747
boolabbreviate=ssup->abbreviate;
1747-
boollocale_aware= false;
1748+
boolcollate_c= false;
17481749
TextSortSupport*tss;
17491750

17501751
#ifdefHAVE_LOCALE_T
@@ -1769,15 +1770,17 @@ btsortsupport_worker(SortSupport ssup, Oid collid)
17691770
* bttextcmp() via the fmgr trampoline.
17701771
*/
17711772
if (lc_collate_is_c(collid))
1773+
{
17721774
ssup->comparator=bttextfastcmp_c;
1775+
collate_c= true;
1776+
}
17731777
#ifdefWIN32
17741778
elseif (GetDatabaseEncoding()==PG_UTF8)
17751779
return;
17761780
#endif
17771781
else
17781782
{
17791783
ssup->comparator=bttextfastcmp_locale;
1780-
locale_aware= true;
17811784

17821785
/*
17831786
* We need a collation-sensitive comparison. To make things faster,
@@ -1798,7 +1801,7 @@ btsortsupport_worker(SortSupport ssup, Oid collid)
17981801
errhint("Use the COLLATE clause to set the collation explicitly.")));
17991802
}
18001803
#ifdefHAVE_LOCALE_T
1801-
tss->locale=pg_newlocale_from_collation(collid);
1804+
locale=pg_newlocale_from_collation(collid);
18021805
#endif
18031806
}
18041807
}
@@ -1828,7 +1831,7 @@ btsortsupport_worker(SortSupport ssup, Oid collid)
18281831
* will make use of the temporary buffers we initialize here for scratch
18291832
* space, and the abbreviation case requires additional state.
18301833
*/
1831-
if (abbreviate||locale_aware)
1834+
if (abbreviate||!collate_c)
18321835
{
18331836
tss=palloc(sizeof(TextSortSupport));
18341837
tss->buf1=palloc(TEXTBUFLEN);
@@ -1838,6 +1841,7 @@ btsortsupport_worker(SortSupport ssup, Oid collid)
18381841
#ifdefHAVE_LOCALE_T
18391842
tss->locale=locale;
18401843
#endif
1844+
tss->collate_c=collate_c;
18411845
ssup->ssup_extra=tss;
18421846

18431847
/*
@@ -2011,45 +2015,58 @@ bttext_abbrev_convert(Datum original, SortSupport ssup)
20112015
memset(pres,0,sizeof(Datum));
20122016
len=VARSIZE_ANY_EXHDR(authoritative);
20132017

2014-
/* By convention, we use buffer 1 to store and NUL-terminate text */
2015-
if (len >=tss->buflen1)
2018+
/*
2019+
* If we're using the C collation, use memcmp(), rather than strxfrm(),
2020+
* to abbreviated keys. The full comparator for the C locale is always
2021+
* memcmp(), and we can't risk having this give a different answer.
2022+
* Besides, this should be faster, too.
2023+
*/
2024+
if (tss->collate_c)
2025+
memcpy(pres,VARDATA_ANY(authoritative),Min(len,sizeof(Datum)));
2026+
else
20162027
{
2017-
pfree(tss->buf1);
2018-
tss->buflen1=Max(len+1,Min(tss->buflen1*2,MaxAllocSize));
2019-
tss->buf1=palloc(tss->buflen1);
2020-
}
2028+
/*
2029+
* We're not using the C collation, so fall back on strxfrm.
2030+
*/
20212031

2022-
/* Just like strcoll(), strxfrm() expects a NUL-terminated string */
2023-
memcpy(tss->buf1,VARDATA_ANY(authoritative),len);
2024-
tss->buf1[len]='\0';
2032+
/* By convention, we use buffer 1 to store and NUL-terminate text */
2033+
if (len >=tss->buflen1)
2034+
{
2035+
pfree(tss->buf1);
2036+
tss->buflen1=Max(len+1,Min(tss->buflen1*2,MaxAllocSize));
2037+
tss->buf1=palloc(tss->buflen1);
2038+
}
20252039

2026-
/*Don't leak memory here */
2027-
if (PointerGetDatum(authoritative)!=original)
2028-
pfree(authoritative);
2040+
/*Just like strcoll(), strxfrm() expects a NUL-terminated string */
2041+
memcpy(tss->buf1,VARDATA_ANY(authoritative),len);
2042+
tss->buf1[len]='\0';
20292043

2030-
retry:
2044+
/* Don't leak memory here */
2045+
if (PointerGetDatum(authoritative)!=original)
2046+
pfree(authoritative);
20312047

2032-
/*
2033-
* There is no special handling of the C locale here, unlike with
2034-
* varstr_cmp(). strxfrm() is used indifferently.
2035-
*/
2048+
for (;;)
2049+
{
20362050
#ifdefHAVE_LOCALE_T
2037-
if (tss->locale)
2038-
bsize=strxfrm_l(tss->buf2,tss->buf1,tss->buflen2,tss->locale);
2039-
else
2051+
if (tss->locale)
2052+
bsize=strxfrm_l(tss->buf2,tss->buf1,
2053+
tss->buflen2,tss->locale);
2054+
else
20402055
#endif
2041-
bsize=strxfrm(tss->buf2,tss->buf1,tss->buflen2);
2056+
bsize=strxfrm(tss->buf2,tss->buf1,tss->buflen2);
20422057

2043-
if (bsize >=tss->buflen2)
2044-
{
2045-
/*
2046-
* The C standard states that the contents of the buffer is now
2047-
* unspecified. Grow buffer, and retry.
2048-
*/
2049-
pfree(tss->buf2);
2050-
tss->buflen2=Max(bsize+1,Min(tss->buflen2*2,MaxAllocSize));
2051-
tss->buf2=palloc(tss->buflen2);
2052-
gotoretry;
2058+
if (bsize<tss->buflen2)
2059+
break;
2060+
2061+
/*
2062+
* The C standard states that the contents of the buffer is now
2063+
* unspecified. Grow buffer, and retry.
2064+
*/
2065+
pfree(tss->buf2);
2066+
tss->buflen2=Max(bsize+1,
2067+
Min(tss->buflen2*2,MaxAllocSize));
2068+
tss->buf2=palloc(tss->buflen2);
2069+
}
20532070
}
20542071

20552072
/*

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