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77947c51c0
and aborted transactions have different effects; also teach it not to assume that prepared transactions are always committed. Along the way, simplify the pgstats API by tying counting directly to Relations; I cannot detect any redeeming social value in having stats pointers in HeapScanDesc and IndexScanDesc structures. And fix a few corner cases in which counts might be missed because the relation's pgstat_info pointer hadn't been set.
97 lines
3.2 KiB
C
97 lines
3.2 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) 1996-2007, 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 1.53 2007/05/27 03:50:39 tgl 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 "storage/bufpage.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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bool rs_pageatatime; /* verify visibility page-at-a-time? */
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/* scan current state */
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bool rs_inited; /* false = scan not init'd yet */
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HeapTupleData rs_ctup; /* current tuple in scan, if any */
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BlockNumber rs_cblock; /* current block # 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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/* these fields only used in page-at-a-time mode */
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int rs_cindex; /* current tuple's index in vistuples */
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int rs_mindex; /* marked tuple's saved index */
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int rs_ntuples; /* number of visible tuples on page */
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OffsetNumber rs_vistuples[MaxHeapTuplesPerPage]; /* their offsets */
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} HeapScanDescData;
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typedef HeapScanDescData *HeapScanDesc;
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/*
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* We use the same IndexScanDescData structure for both amgettuple-based
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* and amgetmulti-based index scans. Some fields are only relevant in
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* amgettuple-based scans.
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*/
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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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bool is_multiscan; /* TRUE = using amgetmulti */
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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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/* index access method's private state */
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void *opaque; /* access-method-specific info */
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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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} IndexScanDescData;
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typedef IndexScanDescData *IndexScanDesc;
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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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