diff options
Diffstat (limited to 'src/backend/optimizer/path/indxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/indxpath.c | 277 |
1 files changed, 22 insertions, 255 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 98c5112f7c3..06f9cd0247f 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,22 +9,20 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.82 2000/04/12 17:15:19 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.83 2000/04/16 04:41:01 tgl Exp $ * *------------------------------------------------------------------------- */ -#include <ctype.h> -#include <math.h> - #include "postgres.h" +#include <math.h> + #include "access/heapam.h" #include "access/nbtree.h" #include "catalog/catname.h" #include "catalog/pg_amop.h" #include "catalog/pg_operator.h" #include "executor/executor.h" -#include "mb/pg_wchar.h" #include "nodes/makefuncs.h" #include "nodes/nodeFuncs.h" #include "optimizer/clauses.h" @@ -46,11 +44,6 @@ #define is_indexable_operator(clause,opclass,relam,indexkey_on_left) \ (indexable_operator(clause,opclass,relam,indexkey_on_left) != InvalidOid) -typedef enum -{ - Prefix_None, Prefix_Partial, Prefix_Exact -} Prefix_Status; - static void match_index_orclauses(RelOptInfo *rel, IndexOptInfo *index, List *restrictinfo_list); static List *match_index_orclause(RelOptInfo *rel, IndexOptInfo *index, @@ -92,17 +85,11 @@ static bool function_index_operand(Expr *funcOpnd, RelOptInfo *rel, IndexOptInfo *index); static bool match_special_index_operator(Expr *clause, Oid opclass, Oid relam, bool indexkey_on_left); -static Prefix_Status like_fixed_prefix(char *patt, char **prefix); -static Prefix_Status regex_fixed_prefix(char *patt, bool case_insensitive, - char **prefix); static List *prefix_quals(Var *leftop, Oid expr_op, - char *prefix, Prefix_Status pstatus); -static char *make_greater_string(const char *str, Oid datatype); + char *prefix, Pattern_Prefix_Status pstatus); static Oid find_operator(const char *opname, Oid datatype); static Datum string_to_datum(const char *str, Oid datatype); static Const *string_to_const(const char *str, Oid datatype); -static bool string_lessthan(const char *str1, const char *str2, - Oid datatype); /* @@ -1644,6 +1631,7 @@ match_special_index_operator(Expr *clause, Oid opclass, Oid relam, Datum constvalue; char *patt; char *prefix; + char *rest; /* * Currently, all known special operators require the indexkey on the @@ -1672,7 +1660,8 @@ match_special_index_operator(Expr *clause, Oid opclass, Oid relam, case OID_NAME_LIKE_OP: /* the right-hand const is type text for all of these */ patt = textout((text *) DatumGetPointer(constvalue)); - isIndexable = like_fixed_prefix(patt, &prefix) != Prefix_None; + isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Like, + &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); @@ -1684,7 +1673,8 @@ match_special_index_operator(Expr *clause, Oid opclass, Oid relam, case OID_NAME_REGEXEQ_OP: /* the right-hand const is type text for all of these */ patt = textout((text *) DatumGetPointer(constvalue)); - isIndexable = regex_fixed_prefix(patt, false, &prefix) != Prefix_None; + isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex, + &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); @@ -1696,7 +1686,8 @@ match_special_index_operator(Expr *clause, Oid opclass, Oid relam, case OID_NAME_ICREGEXEQ_OP: /* the right-hand const is type text for all of these */ patt = textout((text *) DatumGetPointer(constvalue)); - isIndexable = regex_fixed_prefix(patt, true, &prefix) != Prefix_None; + isIndexable = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, + &prefix, &rest) != Pattern_Prefix_None; if (prefix) pfree(prefix); pfree(patt); @@ -1776,7 +1767,8 @@ expand_indexqual_conditions(List *indexquals) Datum constvalue; char *patt; char *prefix; - Prefix_Status pstatus; + char *rest; + Pattern_Prefix_Status pstatus; switch (expr_op) { @@ -1794,7 +1786,8 @@ expand_indexqual_conditions(List *indexquals) /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = textout((text *) DatumGetPointer(constvalue)); - pstatus = like_fixed_prefix(patt, &prefix); + pstatus = pattern_fixed_prefix(patt, Pattern_Type_Like, + &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); @@ -1810,7 +1803,8 @@ expand_indexqual_conditions(List *indexquals) /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = textout((text *) DatumGetPointer(constvalue)); - pstatus = regex_fixed_prefix(patt, false, &prefix); + pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex, + &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); @@ -1826,7 +1820,8 @@ expand_indexqual_conditions(List *indexquals) /* the right-hand const is type text for all of these */ constvalue = ((Const *) rightop)->constvalue; patt = textout((text *) DatumGetPointer(constvalue)); - pstatus = regex_fixed_prefix(patt, true, &prefix); + pstatus = pattern_fixed_prefix(patt, Pattern_Type_Regex_IC, + &prefix, &rest); resultquals = nconc(resultquals, prefix_quals(leftop, expr_op, prefix, pstatus)); @@ -1845,130 +1840,6 @@ expand_indexqual_conditions(List *indexquals) } /* - * Extract the fixed prefix, if any, for a LIKE pattern. - * *prefix is set to a palloc'd prefix string, - * or to NULL if no fixed prefix exists for the pattern. - * The return value distinguishes no fixed prefix, a partial prefix, - * or an exact-match-only pattern. - */ -static Prefix_Status -like_fixed_prefix(char *patt, char **prefix) -{ - char *match; - int pos, - match_pos; - - *prefix = match = palloc(strlen(patt) + 1); - match_pos = 0; - - for (pos = 0; patt[pos]; pos++) - { - /* % and _ are wildcard characters in LIKE */ - if (patt[pos] == '%' || - patt[pos] == '_') - break; - /* Backslash quotes the next character */ - if (patt[pos] == '\\') - { - pos++; - if (patt[pos] == '\0') - break; - } - - /* - * NOTE: this code used to think that %% meant a literal %, but - * textlike() itself does not think that, and the SQL92 spec - * doesn't say any such thing either. - */ - match[match_pos++] = patt[pos]; - } - - match[match_pos] = '\0'; - - /* in LIKE, an empty pattern is an exact match! */ - if (patt[pos] == '\0') - return Prefix_Exact; /* reached end of pattern, so exact */ - - if (match_pos > 0) - return Prefix_Partial; - return Prefix_None; -} - -/* - * Extract the fixed prefix, if any, for a regex pattern. - * *prefix is set to a palloc'd prefix string, - * or to NULL if no fixed prefix exists for the pattern. - * The return value distinguishes no fixed prefix, a partial prefix, - * or an exact-match-only pattern. - */ -static Prefix_Status -regex_fixed_prefix(char *patt, bool case_insensitive, - char **prefix) -{ - char *match; - int pos, - match_pos; - - *prefix = NULL; - - /* Pattern must be anchored left */ - if (patt[0] != '^') - return Prefix_None; - - /* Cannot optimize if unquoted | { } is present in pattern */ - for (pos = 1; patt[pos]; pos++) - { - if (patt[pos] == '|' || - patt[pos] == '{' || - patt[pos] == '}') - return Prefix_None; - if (patt[pos] == '\\') - { - pos++; - if (patt[pos] == '\0') - break; - } - } - - /* OK, allocate space for pattern */ - *prefix = match = palloc(strlen(patt) + 1); - match_pos = 0; - - /* note start at pos 1 to skip leading ^ */ - for (pos = 1; patt[pos]; pos++) - { - if (patt[pos] == '.' || - patt[pos] == '?' || - patt[pos] == '*' || - patt[pos] == '[' || - patt[pos] == '$' || - - /* - * XXX I suspect isalpha() is not an adequately locale-sensitive - * test for characters that can vary under case folding? - */ - (case_insensitive && isalpha(patt[pos]))) - break; - if (patt[pos] == '\\') - { - pos++; - if (patt[pos] == '\0') - break; - } - match[match_pos++] = patt[pos]; - } - - match[match_pos] = '\0'; - - if (patt[pos] == '$' && patt[pos + 1] == '\0') - return Prefix_Exact; /* pattern specifies exact match */ - - if (match_pos > 0) - return Prefix_Partial; - return Prefix_None; -} - -/* * Given a fixed prefix that all the "leftop" values must have, * generate suitable indexqual condition(s). expr_op is the original * LIKE or regex operator; we use it to deduce the appropriate comparison @@ -1976,7 +1847,7 @@ regex_fixed_prefix(char *patt, bool case_insensitive, */ static List * prefix_quals(Var *leftop, Oid expr_op, - char *prefix, Prefix_Status pstatus) + char *prefix, Pattern_Prefix_Status pstatus) { List *result; Oid datatype; @@ -1986,7 +1857,7 @@ prefix_quals(Var *leftop, Oid expr_op, Expr *expr; char *greaterstr; - Assert(pstatus != Prefix_None); + Assert(pstatus != Pattern_Prefix_None); switch (expr_op) { @@ -2022,7 +1893,7 @@ prefix_quals(Var *leftop, Oid expr_op, /* * If we found an exact-match pattern, generate an "=" indexqual. */ - if (pstatus == Prefix_Exact) + if (pstatus == Pattern_Prefix_Exact) { oproid = find_operator("=", datatype); if (oproid == InvalidOid) @@ -2068,68 +1939,6 @@ prefix_quals(Var *leftop, Oid expr_op, } /* - * Try to generate a string greater than the given string or any string it is - * a prefix of. If successful, return a palloc'd string; else return NULL. - * - * To work correctly in non-ASCII locales with weird collation orders, - * we cannot simply increment "foo" to "fop" --- we have to check whether - * we actually produced a string greater than the given one. If not, - * increment the righthand byte again and repeat. If we max out the righthand - * byte, truncate off the last character and start incrementing the next. - * For example, if "z" were the last character in the sort order, then we - * could produce "foo" as a string greater than "fonz". - * - * This could be rather slow in the worst case, but in most cases we won't - * have to try more than one or two strings before succeeding. - * - * XXX in a sufficiently weird locale, this might produce incorrect results? - * For example, in German I believe "ss" is treated specially --- if we are - * given "foos" and return "foot", will this actually be greater than "fooss"? - */ -static char * -make_greater_string(const char *str, Oid datatype) -{ - char *workstr; - int len; - - /* - * Make a modifiable copy, which will be our return value if - * successful - */ - workstr = pstrdup((char *) str); - - while ((len = strlen(workstr)) > 0) - { - unsigned char *lastchar = (unsigned char *) (workstr + len - 1); - - /* - * Try to generate a larger string by incrementing the last byte. - */ - while (*lastchar < (unsigned char) 255) - { - (*lastchar)++; - if (string_lessthan(str, workstr, datatype)) - return workstr; /* Success! */ - } - - /* - * Truncate off the last character, which might be more than 1 - * byte in MULTIBYTE case. - */ -#ifdef MULTIBYTE - len = pg_mbcliplen((const unsigned char *) workstr, len, len - 1); - workstr[len] = '\0'; -#else - *lastchar = '\0'; -#endif - } - - /* Failed... */ - pfree(workstr); - return NULL; -} - -/* * Handy subroutines for match_special_index_operator() and friends. */ @@ -2179,45 +1988,3 @@ string_to_const(const char *str, Oid datatype) return makeConst(datatype, ((datatype == NAMEOID) ? NAMEDATALEN : -1), conval, false, false, false, false); } - -/* - * Test whether two strings are "<" according to the rules of the given - * datatype. We do this the hard way, ie, actually calling the type's - * "<" operator function, to ensure we get the right result... - */ -static bool -string_lessthan(const char *str1, const char *str2, Oid datatype) -{ - Datum datum1 = string_to_datum(str1, datatype); - Datum datum2 = string_to_datum(str2, datatype); - bool result; - - switch (datatype) - { - case TEXTOID: - result = text_lt((text *) datum1, (text *) datum2); - break; - - case BPCHAROID: - result = bpcharlt((char *) datum1, (char *) datum2); - break; - - case VARCHAROID: - result = varcharlt((char *) datum1, (char *) datum2); - break; - - case NAMEOID: - result = namelt((NameData *) datum1, (NameData *) datum2); - break; - - default: - elog(ERROR, "string_lessthan: unexpected datatype %u", datatype); - result = false; - break; - } - - pfree(DatumGetPointer(datum1)); - pfree(DatumGetPointer(datum2)); - - return result; -} |