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111 lines
3.5 KiB
C
111 lines
3.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* relscan.h
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* POSTGRES relation scan descriptor definitions.
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*
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*
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* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/access/relscan.h,v 1.36 2004/08/29 04:13:03 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef RELSCAN_H
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#define RELSCAN_H
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#include "access/skey.h"
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#include "utils/tqual.h"
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typedef struct HeapScanDescData
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{
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/* scan parameters */
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Relation rs_rd; /* heap relation descriptor */
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Snapshot rs_snapshot; /* snapshot to see */
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int rs_nkeys; /* number of scan keys */
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ScanKey rs_key; /* array of scan key descriptors */
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BlockNumber rs_nblocks; /* number of blocks to scan */
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/* scan current state */
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HeapTupleData rs_ctup; /* current tuple in scan, if any */
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Buffer rs_cbuf; /* current buffer in scan, if any */
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/* NB: if rs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
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ItemPointerData rs_mctid; /* marked scan position, if any */
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PgStat_Info rs_pgstat_info; /* statistics collector hook */
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} HeapScanDescData;
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typedef HeapScanDescData *HeapScanDesc;
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typedef struct IndexScanDescData
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{
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/* scan parameters */
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Relation heapRelation; /* heap relation descriptor, or NULL */
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Relation indexRelation; /* index relation descriptor */
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Snapshot xs_snapshot; /* snapshot to see */
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int numberOfKeys; /* number of scan keys */
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ScanKey keyData; /* array of scan key descriptors */
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/* signaling to index AM about killing index tuples */
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bool kill_prior_tuple; /* last-returned tuple is dead */
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bool ignore_killed_tuples; /* do not return killed entries */
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/* set by index AM if scan keys satisfy index's uniqueness constraint */
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bool keys_are_unique;
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/* scan current state */
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bool got_tuple; /* true after successful index_getnext */
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void *opaque; /* access-method-specific info */
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ItemPointerData currentItemData; /* current index pointer */
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ItemPointerData currentMarkData; /* marked position, if any */
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/*
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* xs_ctup/xs_cbuf are valid after a successful index_getnext. After
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* index_getnext_indexitem, xs_ctup.t_self contains the heap tuple TID
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* from the index entry, but its other fields are not valid.
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*/
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HeapTupleData xs_ctup; /* current heap tuple, if any */
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Buffer xs_cbuf; /* current heap buffer in scan, if any */
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/* NB: if xs_cbuf is not InvalidBuffer, we hold a pin on that buffer */
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FmgrInfo fn_getnext; /* cached lookup info for AM's getnext fn */
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/*
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* If keys_are_unique and got_tuple are both true, we stop calling the
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* index AM; it is then necessary for index_getnext to keep track of
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* the logical scan position for itself. It does that using
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* unique_tuple_pos: -1 = before row, 0 = on row, +1 = after row.
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*/
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int unique_tuple_pos; /* logical position */
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int unique_tuple_mark; /* logical marked position */
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PgStat_Info xs_pgstat_info; /* statistics collector hook */
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} IndexScanDescData;
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typedef IndexScanDescData *IndexScanDesc;
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/* ----------------
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* IndexScanDescPtr is used in the executor where we have to
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* keep track of several index scans when using several indices
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* - cim 9/10/89
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* ----------------
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*/
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typedef IndexScanDesc *IndexScanDescPtr;
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/*
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* HeapScanIsValid
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* True iff the heap scan is valid.
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*/
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#define HeapScanIsValid(scan) PointerIsValid(scan)
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/*
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* IndexScanIsValid
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* True iff the index scan is valid.
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*/
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#define IndexScanIsValid(scan) PointerIsValid(scan)
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#endif /* RELSCAN_H */
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