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911e702077
PostgreSQL provides set of template index access methods, where opclasses have much freedom in the semantics of indexing. These index AMs are GiST, GIN, SP-GiST and BRIN. There opclasses define representation of keys, operations on them and supported search strategies. So, it's natural that opclasses may be faced some tradeoffs, which require user-side decision. This commit implements opclass parameters allowing users to set some values, which tell opclass how to index the particular dataset. This commit doesn't introduce new storage in system catalog. Instead it uses pg_attribute.attoptions, which is used for table column storage options but unused for index attributes. In order to evade changing signature of each opclass support function, we implement unified way to pass options to opclass support functions. Options are set to fn_expr as the constant bytea expression. It's possible due to the fact that opclass support functions are executed outside of expressions, so fn_expr is unused for them. This commit comes with some examples of opclass options usage. We parametrize signature length in GiST. That applies to multiple opclasses: tsvector_ops, gist__intbig_ops, gist_ltree_ops, gist__ltree_ops, gist_trgm_ops and gist_hstore_ops. Also we parametrize maximum number of integer ranges for gist__int_ops. However, the main future usage of this feature is expected to be json, where users would be able to specify which way to index particular json parts. Catversion is bumped. Discussion: https://postgr.es/m/d22c3a18-31c7-1879-fc11-4c1ce2f5e5af%40postgrespro.ru Author: Nikita Glukhov, revised by me Reviwed-by: Nikolay Shaplov, Robert Haas, Tom Lane, Tomas Vondra, Alvaro Herrera
140 lines
4.9 KiB
C
140 lines
4.9 KiB
C
/*
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* contrib/pg_trgm/trgm.h
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*/
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#ifndef __TRGM_H__
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#define __TRGM_H__
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#include "access/gist.h"
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#include "access/itup.h"
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#include "access/stratnum.h"
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#include "storage/bufpage.h"
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/*
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* Options ... but note that trgm_regexp.c effectively assumes these values
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* of LPADDING and RPADDING.
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*/
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#define LPADDING 2
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#define RPADDING 1
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#define KEEPONLYALNUM
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/*
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* Caution: IGNORECASE macro means that trigrams are case-insensitive.
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* If this macro is disabled, the ~* and ~~* operators must be removed from
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* the operator classes, because we can't handle case-insensitive wildcard
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* search with case-sensitive trigrams. Failure to do this will result in
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* "cannot handle ~*(~~*) with case-sensitive trigrams" errors.
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*/
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#define IGNORECASE
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#define DIVUNION
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/* operator strategy numbers */
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#define SimilarityStrategyNumber 1
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#define DistanceStrategyNumber 2
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#define LikeStrategyNumber 3
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#define ILikeStrategyNumber 4
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#define RegExpStrategyNumber 5
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#define RegExpICaseStrategyNumber 6
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#define WordSimilarityStrategyNumber 7
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#define WordDistanceStrategyNumber 8
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#define StrictWordSimilarityStrategyNumber 9
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#define StrictWordDistanceStrategyNumber 10
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typedef char trgm[3];
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#define CMPCHAR(a,b) ( ((a)==(b)) ? 0 : ( ((a)<(b)) ? -1 : 1 ) )
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#define CMPPCHAR(a,b,i) CMPCHAR( *(((const char*)(a))+i), *(((const char*)(b))+i) )
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#define CMPTRGM(a,b) ( CMPPCHAR(a,b,0) ? CMPPCHAR(a,b,0) : ( CMPPCHAR(a,b,1) ? CMPPCHAR(a,b,1) : CMPPCHAR(a,b,2) ) )
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#define CPTRGM(a,b) do { \
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*(((char*)(a))+0) = *(((char*)(b))+0); \
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*(((char*)(a))+1) = *(((char*)(b))+1); \
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*(((char*)(a))+2) = *(((char*)(b))+2); \
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} while(0);
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#ifdef KEEPONLYALNUM
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#define ISWORDCHR(c) (t_isalpha(c) || t_isdigit(c))
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#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && (isalnum( *(unsigned char*)(a) ) || *(unsigned char*)(a)==' ') )
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#else
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#define ISWORDCHR(c) (!t_isspace(c))
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#define ISPRINTABLECHAR(a) ( isascii( *(unsigned char*)(a) ) && isprint( *(unsigned char*)(a) ) )
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#endif
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#define ISPRINTABLETRGM(t) ( ISPRINTABLECHAR( ((char*)(t)) ) && ISPRINTABLECHAR( ((char*)(t))+1 ) && ISPRINTABLECHAR( ((char*)(t))+2 ) )
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#define ISESCAPECHAR(x) (*(x) == '\\') /* Wildcard escape character */
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#define ISWILDCARDCHAR(x) (*(x) == '_' || *(x) == '%') /* Wildcard
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* meta-character */
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typedef struct
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{
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int32 vl_len_; /* varlena header (do not touch directly!) */
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uint8 flag;
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char data[FLEXIBLE_ARRAY_MEMBER];
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} TRGM;
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#define TRGMHDRSIZE (VARHDRSZ + sizeof(uint8))
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/* gist */
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#define SIGLEN_DEFAULT (sizeof(int) * 3)
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#define SIGLEN_MAX GISTMaxIndexKeySize
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#define BITBYTE 8
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#define SIGLENBIT(siglen) ((siglen) * BITBYTE - 1) /* see makesign */
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typedef char *BITVECP;
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#define LOOPBYTE(siglen) \
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for (i = 0; i < (siglen); i++)
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#define GETBYTE(x,i) ( *( (BITVECP)(x) + (int)( (i) / BITBYTE ) ) )
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#define GETBITBYTE(x,i) ( (((char)(x)) >> (i)) & 0x01 )
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#define CLRBIT(x,i) GETBYTE(x,i) &= ~( 0x01 << ( (i) % BITBYTE ) )
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#define SETBIT(x,i) GETBYTE(x,i) |= ( 0x01 << ( (i) % BITBYTE ) )
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#define GETBIT(x,i) ( (GETBYTE(x,i) >> ( (i) % BITBYTE )) & 0x01 )
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#define HASHVAL(val, siglen) (((unsigned int)(val)) % SIGLENBIT(siglen))
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#define HASH(sign, val, siglen) SETBIT((sign), HASHVAL(val, siglen))
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#define ARRKEY 0x01
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#define SIGNKEY 0x02
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#define ALLISTRUE 0x04
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#define ISARRKEY(x) ( ((TRGM*)x)->flag & ARRKEY )
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#define ISSIGNKEY(x) ( ((TRGM*)x)->flag & SIGNKEY )
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#define ISALLTRUE(x) ( ((TRGM*)x)->flag & ALLISTRUE )
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#define CALCGTSIZE(flag, len) ( TRGMHDRSIZE + ( ( (flag) & ARRKEY ) ? ((len)*sizeof(trgm)) : (((flag) & ALLISTRUE) ? 0 : (len)) ) )
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#define GETSIGN(x) ( (BITVECP)( (char*)x+TRGMHDRSIZE ) )
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#define GETARR(x) ( (trgm*)( (char*)x+TRGMHDRSIZE ) )
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#define ARRNELEM(x) ( ( VARSIZE(x) - TRGMHDRSIZE )/sizeof(trgm) )
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/*
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* If DIVUNION is defined then similarity formula is:
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* count / (len1 + len2 - count)
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* else if DIVUNION is not defined then similarity formula is:
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* count / max(len1, len2)
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*/
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#ifdef DIVUNION
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#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) ((len1) + (len2) - (count)))
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#else
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#define CALCSML(count, len1, len2) ((float4) (count)) / ((float4) (((len1) > (len2)) ? (len1) : (len2)))
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#endif
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typedef struct TrgmPackedGraph TrgmPackedGraph;
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extern double similarity_threshold;
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extern double word_similarity_threshold;
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extern double strict_word_similarity_threshold;
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extern double index_strategy_get_limit(StrategyNumber strategy);
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extern uint32 trgm2int(trgm *ptr);
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extern void compact_trigram(trgm *tptr, char *str, int bytelen);
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extern TRGM *generate_trgm(char *str, int slen);
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extern TRGM *generate_wildcard_trgm(const char *str, int slen);
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extern float4 cnt_sml(TRGM *trg1, TRGM *trg2, bool inexact);
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extern bool trgm_contained_by(TRGM *trg1, TRGM *trg2);
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extern bool *trgm_presence_map(TRGM *query, TRGM *key);
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extern TRGM *createTrgmNFA(text *text_re, Oid collation,
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TrgmPackedGraph **graph, MemoryContext rcontext);
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extern bool trigramsMatchGraph(TrgmPackedGraph *graph, bool *check);
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#endif /* __TRGM_H__ */
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