| /*------------------------------------------------------------------------- |
| * |
| * skey.h |
| * POSTGRES scan key definitions. |
| * |
| * |
| * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group |
| * Portions Copyright (c) 1994, Regents of the University of California |
| * |
| * src/include/access/skey.h |
| * |
| *------------------------------------------------------------------------- |
| */ |
| #ifndef SKEY_H |
| #define SKEY_H |
| |
| #include "access/attnum.h" |
| #include "access/stratnum.h" |
| #include "fmgr.h" |
| |
| |
| /* |
| * A ScanKey represents the application of a comparison operator between |
| * a table or index column and a constant. When it's part of an array of |
| * ScanKeys, the comparison conditions are implicitly ANDed. The index |
| * column is the left argument of the operator, if it's a binary operator. |
| * (The data structure can support unary indexable operators too; in that |
| * case sk_argument would go unused. This is not currently implemented.) |
| * |
| * For an index scan, sk_strategy and sk_subtype must be set correctly for |
| * the operator. When using a ScanKey in a heap scan, these fields are not |
| * used and may be set to InvalidStrategy/InvalidOid. |
| * |
| * If the operator is collation-sensitive, sk_collation must be set |
| * correctly as well. |
| * |
| * A ScanKey can also represent a ScalarArrayOpExpr, that is a condition |
| * "column op ANY(ARRAY[...])". This is signaled by the SK_SEARCHARRAY |
| * flag bit. The sk_argument is not a value of the operator's right-hand |
| * argument type, but rather an array of such values, and the per-element |
| * comparisons are to be ORed together. |
| * |
| * A ScanKey can also represent a condition "column IS NULL" or "column |
| * IS NOT NULL"; these cases are signaled by the SK_SEARCHNULL and |
| * SK_SEARCHNOTNULL flag bits respectively. The argument is always NULL, |
| * and the sk_strategy, sk_subtype, sk_collation, and sk_func fields are |
| * not used (unless set by the index AM). |
| * |
| * SK_SEARCHARRAY, SK_SEARCHNULL and SK_SEARCHNOTNULL are supported only |
| * for index scans, not heap scans; and not all index AMs support them, |
| * only those that set amsearcharray or amsearchnulls respectively. |
| * |
| * A ScanKey can also represent an ordering operator invocation, that is |
| * an ordering requirement "ORDER BY indexedcol op constant". This looks |
| * the same as a comparison operator, except that the operator doesn't |
| * (usually) yield boolean. We mark such ScanKeys with SK_ORDER_BY. |
| * SK_SEARCHARRAY, SK_SEARCHNULL, SK_SEARCHNOTNULL cannot be used here. |
| * |
| * Note: in some places, ScanKeys are used as a convenient representation |
| * for the invocation of an access method support procedure. In this case |
| * sk_strategy/sk_subtype are not meaningful (but sk_collation can be); and |
| * sk_func may refer to a function that returns something other than boolean. |
| */ |
| typedef struct ScanKeyData |
| { |
| int sk_flags; /* flags, see below */ |
| AttrNumber sk_attno; /* table or index column number */ |
| StrategyNumber sk_strategy; /* operator strategy number */ |
| Oid sk_subtype; /* strategy subtype */ |
| Oid sk_collation; /* collation to use, if needed */ |
| FmgrInfo sk_func; /* lookup info for function to call */ |
| Datum sk_argument; /* data to compare */ |
| } ScanKeyData; |
| |
| typedef ScanKeyData *ScanKey; |
| |
| /* |
| * About row comparisons: |
| * |
| * The ScanKey data structure also supports row comparisons, that is ordered |
| * tuple comparisons like (x, y) > (c1, c2), having the SQL-spec semantics |
| * "x > c1 OR (x = c1 AND y > c2)". Note that this is currently only |
| * implemented for btree index searches, not for heapscans or any other index |
| * type. A row comparison is represented by a "header" ScanKey entry plus |
| * a separate array of ScanKeys, one for each column of the row comparison. |
| * The header entry has these properties: |
| * sk_flags = SK_ROW_HEADER |
| * sk_attno = index column number for leading column of row comparison |
| * sk_strategy = btree strategy code for semantics of row comparison |
| * (ie, < <= > or >=) |
| * sk_subtype, sk_collation, sk_func: not used |
| * sk_argument: pointer to subsidiary ScanKey array |
| * If the header is part of a ScanKey array that's sorted by attno, it |
| * must be sorted according to the leading column number. |
| * |
| * The subsidiary ScanKey array appears in logical column order of the row |
| * comparison, which may be different from index column order. The array |
| * elements are like a normal ScanKey array except that: |
| * sk_flags must include SK_ROW_MEMBER, plus SK_ROW_END in the last |
| * element (needed since row header does not include a count) |
| * sk_func points to the btree comparison support function for the |
| * opclass, NOT the operator's implementation function. |
| * sk_strategy must be the same in all elements of the subsidiary array, |
| * that is, the same as in the header entry. |
| * SK_SEARCHARRAY, SK_SEARCHNULL, SK_SEARCHNOTNULL cannot be used here. |
| */ |
| |
| /* |
| * ScanKeyData sk_flags |
| * |
| * sk_flags bits 0-15 are reserved for system-wide use (symbols for those |
| * bits should be defined here). Bits 16-31 are reserved for use within |
| * individual index access methods. |
| */ |
| #define SK_ISNULL 0x0001 /* sk_argument is NULL */ |
| #define SK_UNARY 0x0002 /* unary operator (not supported!) */ |
| #define SK_ROW_HEADER 0x0004 /* row comparison header (see above) */ |
| #define SK_ROW_MEMBER 0x0008 /* row comparison member (see above) */ |
| #define SK_ROW_END 0x0010 /* last row comparison member */ |
| #define SK_SEARCHARRAY 0x0020 /* scankey represents ScalarArrayOp */ |
| #define SK_SEARCHNULL 0x0040 /* scankey represents "col IS NULL" */ |
| #define SK_SEARCHNOTNULL 0x0080 /* scankey represents "col IS NOT NULL" */ |
| #define SK_ORDER_BY 0x0100 /* scankey is for ORDER BY op */ |
| |
| /* for runtime filter */ |
| #define SK_EMPYT 0x8000 /* scankey is empty */ |
| #define SK_BLOOM_FILTER 0x4000 /* scankey is for bloom filter */ |
| |
| /* |
| * prototypes for functions in access/common/scankey.c |
| */ |
| extern void ScanKeyInit(ScanKey entry, |
| AttrNumber attributeNumber, |
| StrategyNumber strategy, |
| RegProcedure procedure, |
| Datum argument); |
| extern void ScanKeyEntryInitialize(ScanKey entry, |
| int flags, |
| AttrNumber attributeNumber, |
| StrategyNumber strategy, |
| Oid subtype, |
| Oid collation, |
| RegProcedure procedure, |
| Datum argument); |
| extern void ScanKeyEntryInitializeWithInfo(ScanKey entry, |
| int flags, |
| AttrNumber attributeNumber, |
| StrategyNumber strategy, |
| Oid subtype, |
| Oid collation, |
| FmgrInfo *finfo, |
| Datum argument); |
| |
| #endif /* SKEY_H */ |
