From cf984672427ebc4446213fe8f71d8899452802b6 Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Sun, 9 Sep 2018 21:19:51 +0300 Subject: [PATCH] Improve behavior of to_timestamp()/to_date() functions to_timestamp()/to_date() functions were introduced mainly for Oracle compatibility, and became very popular among PostgreSQL users. However, some behavior of to_timestamp()/to_date() functions are both incompatible with Oracle and confusing for our users. This behavior is related to handling of spaces and separators in non FX (fixed format) mode. This commit reworks this behavior making less confusing, better documented and more compatible with Oracle. Nevertheless, there are still following incompatibilities with Oracle. 1) We don't insist that there are no format string patterns unmatched to input string. 2) In FX mode we don't insist space and separators in format string to exactly match input string. 3) When format string patterns are divided by mix of spaces and separators, we don't distinguish them, while Oracle takes into account only last group of spaces/separators. Discussion: https://postgr.es/m/1873520224.1784572.1465833145330.JavaMail.yahoo%40mail.yahoo.com Author: Artur Zakirov, Alexander Korotkov, Liudmila Mantrova Review: Amul Sul, Robert Haas, Tom Lane, Dmitry Dolgov, David G. Johnston --- doc/src/sgml/func.sgml | 62 +++++++++++++- src/backend/utils/adt/formatting.c | 112 +++++++++++++++++++++---- src/test/regress/expected/horology.out | 105 +++++++++++++++++++++-- src/test/regress/sql/horology.sql | 27 +++++- 4 files changed, 280 insertions(+), 26 deletions(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 335900a86e..4331bebc96 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -6262,16 +6262,57 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}'); to_timestamp and to_date - skip multiple blank spaces in the input string unless the - FX option is used. For example, - to_timestamp('2000    JUN', 'YYYY MON') works, but + skip multiple blank spaces at the beginning of the input string and + around date and time values unless the FX option is used. For example, + to_timestamp(' 2000    JUN', 'YYYY MON') and + to_timestamp('2000 - JUN', 'YYYY-MON') work, but to_timestamp('2000    JUN', 'FXYYYY MON') returns an error - because to_timestamp expects one space only. + because to_timestamp expects a single space only. FX must be specified as the first item in the template. + + + A separator (a space or a non-letter/non-digit character) in the template string of + to_timestamp and to_date + matches any single separator in the input string or is skipped, + unless the FX option is used. + For example, to_timestamp('2000JUN', 'YYYY///MON') and + to_timestamp('2000/JUN', 'YYYY MON') work, but + to_timestamp('2000//JUN', 'YYYY/MON') + returns an error because the number of separators in the input string + exceeds the number of separators in the template. + + + If FX is specified, separator in template string + matches to exactly one character in input string. Notice we don't insist + input string character to be the same as template string separator. + For example, to_timestamp('2000/JUN', 'FXYYYY MON') + works, but to_timestamp('2000/JUN', 'FXYYYY  MON') + returns an error because a space second template string space consumed + letter J from the input string. + + + + + + TZH template pattern can match a signed number. + Without the FX option, it may lead to ambiguity in + interpretation of the minus sign, which can also be interpreted as a separator. + This ambiguity is resolved as follows. If the number of separators before + TZH in the template string is less than the number of + separators before the minus sign in the input string, the minus sign + is interpreted as part of TZH. + Otherwise, the minus sign is considered to be a separator between values. + For example, to_timestamp('2000 -10', 'YYYY TZH') matches + -10 to TZH, but + to_timestamp('2000 -10', 'YYYY  TZH') + matches 10 to TZH. + + + Ordinary text is allowed in to_char @@ -6287,6 +6328,19 @@ SELECT regexp_match('abc01234xyz', '(?:(.*?)(\d+)(.*)){1,1}'); string; for example "XX" skips two input characters (whether or not they are XX). + + + Prior to PostgreSQL 12, it was possible to + skip arbitrary text in the input string using non-letter or non-digit + characters. For example, + to_timestamp('2000y6m1d', 'yyyy-MM-DD') used to + work. Now you can only use letter characters for this purpose. For example, + to_timestamp('2000y6m1d', 'yyyytMMtDDt') and + to_timestamp('2000y6m1d', 'yyyy"y"MM"m"DD"d"') + skip y, m, and + d. + + diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c index 30696e3575..2ed8ca675b 100644 --- a/src/backend/utils/adt/formatting.c +++ b/src/backend/utils/adt/formatting.c @@ -165,6 +165,8 @@ typedef struct #define NODE_TYPE_END 1 #define NODE_TYPE_ACTION 2 #define NODE_TYPE_CHAR 3 +#define NODE_TYPE_SEPARATOR 4 +#define NODE_TYPE_SPACE 5 #define SUFFTYPE_PREFIX 1 #define SUFFTYPE_POSTFIX 2 @@ -955,6 +957,7 @@ typedef struct NUMProc static const KeyWord *index_seq_search(const char *str, const KeyWord *kw, const int *index); static const KeySuffix *suff_search(const char *str, const KeySuffix *suf, int type); +static bool is_separator_char(const char *str); static void NUMDesc_prepare(NUMDesc *num, FormatNode *n); static void parse_format(FormatNode *node, const char *str, const KeyWord *kw, const KeySuffix *suf, const int *index, int ver, NUMDesc *Num); @@ -1044,6 +1047,16 @@ suff_search(const char *str, const KeySuffix *suf, int type) return NULL; } +static bool +is_separator_char(const char *str) +{ + /* ASCII printable character, but not letter or digit */ + return (*str > 0x20 && *str < 0x7F && + !(*str >= 'A' && *str <= 'Z') && + !(*str >= 'a' && *str <= 'z') && + !(*str >= '0' && *str <= '9')); +} + /* ---------- * Prepare NUMDesc (number description struct) via FormatNode struct * ---------- @@ -1319,7 +1332,14 @@ parse_format(FormatNode *node, const char *str, const KeyWord *kw, if (*str == '\\' && *(str + 1) == '"') str++; chlen = pg_mblen(str); - n->type = NODE_TYPE_CHAR; + + if (ver == DCH_TYPE && is_separator_char(str)) + n->type = NODE_TYPE_SEPARATOR; + else if (isspace((unsigned char) *str)) + n->type = NODE_TYPE_SPACE; + else + n->type = NODE_TYPE_CHAR; + memcpy(n->character, str, chlen); n->character[chlen] = '\0'; n->key = NULL; @@ -2987,27 +3007,66 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out) int len, value; bool fx_mode = false; + /* number of extra skipped characters (more than given in format string) */ + int extra_skip = 0; for (n = node, s = in; n->type != NODE_TYPE_END && *s != '\0'; n++) { - if (n->type != NODE_TYPE_ACTION) + /* + * Ignore spaces at the beginning of the string and before fields when + * not in FX (fixed width) mode. + */ + if (!fx_mode && (n->type != NODE_TYPE_ACTION || n->key->id != DCH_FX) && + (n->type == NODE_TYPE_ACTION || n == node)) + { + while (*s != '\0' && isspace((unsigned char) *s)) + { + s++; + extra_skip++; + } + } + + if (n->type == NODE_TYPE_SPACE || n->type == NODE_TYPE_SEPARATOR) + { + if (!fx_mode) + { + /* + * In non FX (fixed format) mode one format string space or + * separator match to one space or separator in input string. + * Or match nothing if there is no space or separator in + * the current position of input string. + */ + extra_skip--; + if (isspace((unsigned char) *s) || is_separator_char(s)) + { + s++; + extra_skip++; + } + } + else + { + /* + * In FX mode, on format string space or separator we consume + * exactly one character from input string. Notice we don't + * insist that the consumed character match the format's + * character. + */ + s += pg_mblen(s); + } + continue; + } + else if (n->type != NODE_TYPE_ACTION) { /* - * Separator, so consume one character from input string. Notice - * we don't insist that the consumed character match the format's - * character. + * Text character, so consume one character from input string. + * Notice we don't insist that the consumed character match the + * format's character. + * Text field ignores FX mode. */ s += pg_mblen(s); continue; } - /* Ignore spaces before fields when not in FX (fixed width) mode */ - if (!fx_mode && n->key->id != DCH_FX) - { - while (*s != '\0' && isspace((unsigned char) *s)) - s++; - } - from_char_set_mode(out, n->key->date_mode); switch (n->key->id) @@ -3086,10 +3145,24 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out) n->key->name))); break; case DCH_TZH: - out->tzsign = *s == '-' ? -1 : +1; - + /* + * Value of TZH might be negative. And the issue is that we + * might swallow minus sign as the separator. So, if we have + * skipped more characters than specified in the format string, + * then we consider prepending last skipped minus to TZH. + */ if (*s == '+' || *s == '-' || *s == ' ') + { + out->tzsign = *s == '-' ? -1 : +1; s++; + } + else + { + if (extra_skip > 0 && *(s - 1) == '-') + out->tzsign = -1; + else + out->tzsign = +1; + } from_char_parse_int_len(&out->tzh, &s, 2, n); break; @@ -3261,6 +3334,17 @@ DCH_from_char(FormatNode *node, char *in, TmFromChar *out) SKIP_THth(s, n->suffix); break; } + + /* Ignore all spaces after fields */ + if (!fx_mode) + { + extra_skip = 0; + while (*s != '\0' && isspace((unsigned char) *s)) + { + s++; + extra_skip++; + } + } } } diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out index 63e39198e6..7d11f25158 100644 --- a/src/test/regress/expected/horology.out +++ b/src/test/regress/expected/horology.out @@ -2769,14 +2769,32 @@ SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS'); Sat Feb 16 08:14:30 0097 PST (1 row) +SELECT to_timestamp('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS'); + to_timestamp +------------------------------ + Fri Mar 18 23:38:15 2011 PDT +(1 row) + SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD'); to_timestamp ------------------------------ Sat Jan 12 00:00:00 1985 PST (1 row) +SELECT to_timestamp('1985 FMMonth 12', 'YYYY "FMMonth" DD'); + to_timestamp +------------------------------ + Sat Jan 12 00:00:00 1985 PST +(1 row) + +SELECT to_timestamp('1985 \ 12', 'YYYY \\ DD'); + to_timestamp +------------------------------ + Sat Jan 12 00:00:00 1985 PST +(1 row) + SELECT to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16', - '"My birthday-> Year" YYYY, "Month:" FMMonth, "Day:" DD'); + '"My birthday-> Year:" YYYY, "Month:" FMMonth, "Day:" DD'); to_timestamp ------------------------------ Sun May 16 00:00:00 1976 PDT @@ -2789,7 +2807,7 @@ SELECT to_timestamp('1,582nd VIII 21', 'Y,YYYth FMRM DD'); (1 row) SELECT to_timestamp('15 "text between quote marks" 98 54 45', - E'HH24 "\\text between quote marks\\"" YY MI SS'); + E'HH24 "\\"text between quote marks\\"" YY MI SS'); to_timestamp ------------------------------ Thu Jan 01 15:54:45 1998 PST @@ -2810,6 +2828,24 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay'); SELECT to_timestamp('97/Feb/16', 'YYMonDD'); ERROR: invalid value "/Fe" for "Mon" DETAIL: The given value did not match any of the allowed values for this field. +SELECT to_timestamp('97/Feb/16', 'YY:Mon:DD'); + to_timestamp +------------------------------ + Sun Feb 16 00:00:00 1997 PST +(1 row) + +SELECT to_timestamp('97/Feb/16', 'FXYY:Mon:DD'); + to_timestamp +------------------------------ + Sun Feb 16 00:00:00 1997 PST +(1 row) + +SELECT to_timestamp('97/Feb/16', 'FXYY/Mon/DD'); + to_timestamp +------------------------------ + Sun Feb 16 00:00:00 1997 PST +(1 row) + SELECT to_timestamp('19971116', 'YYYYMMDD'); to_timestamp ------------------------------ @@ -2966,7 +3002,7 @@ SELECT to_timestamp('2011-12-18 11:38 20', 'YYYY-MM-DD HH12:MI TZM'); SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); to_timestamp ------------------------------ - Sun Dec 18 03:38:15 2011 PST + Sun Dec 18 23:38:15 2011 PST (1 row) SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); @@ -2996,7 +3032,64 @@ SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); to_timestamp ------------------------------ - Sun Dec 18 03:38:15 2011 PST + Sun Dec 18 23:38:15 2011 PST +(1 row) + +SELECT to_timestamp('2000+ JUN', 'YYYY/MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp(' 2000 +JUN', 'YYYY/MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp(' 2000 +JUN', 'YYYY//MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp('2000 +JUN', 'YYYY//MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp('2000 + JUN', 'YYYY MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp('2000 ++ JUN', 'YYYY MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp('2000 + + JUN', 'YYYY MON'); +ERROR: invalid value "+ J" for "MON" +DETAIL: The given value did not match any of the allowed values for this field. +SELECT to_timestamp('2000 + + JUN', 'YYYY MON'); + to_timestamp +------------------------------ + Thu Jun 01 00:00:00 2000 PDT +(1 row) + +SELECT to_timestamp('2000 -10', 'YYYY TZH'); + to_timestamp +------------------------------ + Sat Jan 01 02:00:00 2000 PST +(1 row) + +SELECT to_timestamp('2000 -10', 'YYYY TZH'); + to_timestamp +------------------------------ + Fri Dec 31 06:00:00 1999 PST (1 row) SELECT to_date('2011 12 18', 'YYYY MM DD'); @@ -3014,13 +3107,13 @@ SELECT to_date('2011 12 18', 'YYYY MM DD'); SELECT to_date('2011 12 18', 'YYYY MM DD'); to_date ------------ - 12-08-2011 + 12-18-2011 (1 row) SELECT to_date('2011 12 18', 'YYYY MM DD'); to_date ------------ - 02-18-2011 + 12-18-2011 (1 row) SELECT to_date('2011 12 18', 'YYYY MM DD'); diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql index ebb196a1cf..807037be76 100644 --- a/src/test/regress/sql/horology.sql +++ b/src/test/regress/sql/horology.sql @@ -392,15 +392,21 @@ SELECT to_timestamp('0097/Feb/16 --> 08:14:30', 'YYYY/Mon/DD --> HH:MI:SS'); SELECT to_timestamp('97/2/16 8:14:30', 'FMYYYY/FMMM/FMDD FMHH:FMMI:FMSS'); +SELECT to_timestamp('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS'); + SELECT to_timestamp('1985 January 12', 'YYYY FMMonth DD'); +SELECT to_timestamp('1985 FMMonth 12', 'YYYY "FMMonth" DD'); + +SELECT to_timestamp('1985 \ 12', 'YYYY \\ DD'); + SELECT to_timestamp('My birthday-> Year: 1976, Month: May, Day: 16', - '"My birthday-> Year" YYYY, "Month:" FMMonth, "Day:" DD'); + '"My birthday-> Year:" YYYY, "Month:" FMMonth, "Day:" DD'); SELECT to_timestamp('1,582nd VIII 21', 'Y,YYYth FMRM DD'); SELECT to_timestamp('15 "text between quote marks" 98 54 45', - E'HH24 "\\text between quote marks\\"" YY MI SS'); + E'HH24 "\\"text between quote marks\\"" YY MI SS'); SELECT to_timestamp('05121445482000', 'MMDDHH24MISSYYYY'); @@ -408,6 +414,12 @@ SELECT to_timestamp('2000January09Sunday', 'YYYYFMMonthDDFMDay'); SELECT to_timestamp('97/Feb/16', 'YYMonDD'); +SELECT to_timestamp('97/Feb/16', 'YY:Mon:DD'); + +SELECT to_timestamp('97/Feb/16', 'FXYY:Mon:DD'); + +SELECT to_timestamp('97/Feb/16', 'FXYY/Mon/DD'); + SELECT to_timestamp('19971116', 'YYYYMMDD'); SELECT to_timestamp('20000-1116', 'YYYY-MMDD'); @@ -464,6 +476,17 @@ SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); SELECT to_timestamp('2011-12-18 23:38:15', 'YYYY-MM-DD HH24:MI:SS'); +SELECT to_timestamp('2000+ JUN', 'YYYY/MON'); +SELECT to_timestamp(' 2000 +JUN', 'YYYY/MON'); +SELECT to_timestamp(' 2000 +JUN', 'YYYY//MON'); +SELECT to_timestamp('2000 +JUN', 'YYYY//MON'); +SELECT to_timestamp('2000 + JUN', 'YYYY MON'); +SELECT to_timestamp('2000 ++ JUN', 'YYYY MON'); +SELECT to_timestamp('2000 + + JUN', 'YYYY MON'); +SELECT to_timestamp('2000 + + JUN', 'YYYY MON'); +SELECT to_timestamp('2000 -10', 'YYYY TZH'); +SELECT to_timestamp('2000 -10', 'YYYY TZH'); + SELECT to_date('2011 12 18', 'YYYY MM DD'); SELECT to_date('2011 12 18', 'YYYY MM DD'); SELECT to_date('2011 12 18', 'YYYY MM DD');