Cleanup the usage of ScanDirection: use the symbolic names for the
possible ScanDirection alternatives rather than magic numbers (-1, 0, 1). Also, use the ScanDirection macros in a few places rather than directly checking whether `dir == ForwardScanDirection' and the like. Per patch from James William Pye. His patch also changed ScanDirection to be a "char" rather than an enum, which I haven't applied.
This commit is contained in:
Neil Conway
parent
3666260ffd
commit
737651f6be
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.206 2006/01/11 08:43:11 neilc Exp $
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* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.207 2006/02/21 23:01:53 neilc Exp $
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*
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*
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* INTERFACE ROUTINES
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@ -172,7 +172,8 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
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* tuple as indicated by "dir"; return the next tuple in scan->rs_ctup,
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* or set scan->rs_ctup.t_data = NULL if no more tuples.
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*
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* dir == 0 means "re-fetch the tuple indicated by scan->rs_ctup".
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* dir == NoMovementScanDirection means "re-fetch the tuple indicated
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* by scan->rs_ctup".
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*
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* Note: the reason nkeys/key are passed separately, even though they are
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* kept in the scan descriptor, is that the caller may not want us to check
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@ -189,12 +190,13 @@ heapgetpage(HeapScanDesc scan, BlockNumber page)
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*/
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static void
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heapgettup(HeapScanDesc scan,
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int dir,
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ScanDirection dir,
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int nkeys,
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ScanKey key)
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{
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HeapTuple tuple = &(scan->rs_ctup);
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Snapshot snapshot = scan->rs_snapshot;
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bool backward = ScanDirectionIsBackward(dir);
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BlockNumber page;
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Page dp;
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int lines;
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@ -205,11 +207,8 @@ heapgettup(HeapScanDesc scan,
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/*
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* calculate next starting lineoff, given scan direction
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*/
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if (dir > 0)
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if (ScanDirectionIsForward(dir))
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{
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/*
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* forward scan direction
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*/
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if (!scan->rs_inited)
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{
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/*
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@ -242,11 +241,8 @@ heapgettup(HeapScanDesc scan,
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linesleft = lines - lineoff + 1;
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}
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else if (dir < 0)
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else if (backward)
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{
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/*
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* reverse scan direction
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*/
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if (!scan->rs_inited)
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{
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/*
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@ -352,7 +348,7 @@ heapgettup(HeapScanDesc scan,
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* otherwise move to the next item on the page
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*/
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--linesleft;
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if (dir < 0)
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if (backward)
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{
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--lpp; /* move back in this page's ItemId array */
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--lineoff;
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@ -373,7 +369,7 @@ heapgettup(HeapScanDesc scan,
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/*
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* return NULL if we've exhausted all the pages
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*/
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if ((dir < 0) ? (page == 0) : (page + 1 >= scan->rs_nblocks))
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if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
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{
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if (BufferIsValid(scan->rs_cbuf))
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ReleaseBuffer(scan->rs_cbuf);
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@ -384,7 +380,7 @@ heapgettup(HeapScanDesc scan,
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return;
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}
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page = (dir < 0) ? (page - 1) : (page + 1);
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page = backward ? (page - 1) : (page + 1);
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heapgetpage(scan, page);
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@ -393,7 +389,7 @@ heapgettup(HeapScanDesc scan,
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dp = (Page) BufferGetPage(scan->rs_cbuf);
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lines = PageGetMaxOffsetNumber((Page) dp);
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linesleft = lines;
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if (dir < 0)
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if (backward)
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{
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lineoff = lines;
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lpp = PageGetItemId(dp, lines);
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@ -421,11 +417,12 @@ heapgettup(HeapScanDesc scan,
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*/
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static void
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heapgettup_pagemode(HeapScanDesc scan,
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int dir,
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ScanDirection dir,
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int nkeys,
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ScanKey key)
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{
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HeapTuple tuple = &(scan->rs_ctup);
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bool backward = ScanDirectionIsBackward(dir);
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BlockNumber page;
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Page dp;
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int lines;
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@ -437,11 +434,8 @@ heapgettup_pagemode(HeapScanDesc scan,
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/*
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* calculate next starting lineindex, given scan direction
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*/
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if (dir > 0)
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if (ScanDirectionIsForward(dir))
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{
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/*
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* forward scan direction
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*/
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if (!scan->rs_inited)
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{
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/*
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@ -471,11 +465,8 @@ heapgettup_pagemode(HeapScanDesc scan,
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linesleft = lines - lineindex;
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}
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else if (dir < 0)
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else if (backward)
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{
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/*
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* reverse scan direction
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*/
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if (!scan->rs_inited)
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{
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/*
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@ -584,14 +575,10 @@ heapgettup_pagemode(HeapScanDesc scan,
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* otherwise move to the next item on the page
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*/
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--linesleft;
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if (dir < 0)
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{
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if (backward)
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--lineindex;
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}
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else
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{
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++lineindex;
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}
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}
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/*
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@ -602,7 +589,7 @@ heapgettup_pagemode(HeapScanDesc scan,
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/*
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* return NULL if we've exhausted all the pages
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*/
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if ((dir < 0) ? (page == 0) : (page + 1 >= scan->rs_nblocks))
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if (backward ? (page == 0) : (page + 1 >= scan->rs_nblocks))
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{
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if (BufferIsValid(scan->rs_cbuf))
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ReleaseBuffer(scan->rs_cbuf);
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@ -613,14 +600,13 @@ heapgettup_pagemode(HeapScanDesc scan,
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return;
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}
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page = (dir < 0) ? (page - 1) : (page + 1);
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page = backward ? (page - 1) : (page + 1);
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heapgetpage(scan, page);
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dp = (Page) BufferGetPage(scan->rs_cbuf);
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lines = scan->rs_ntuples;
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linesleft = lines;
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if (dir < 0)
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if (backward)
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lineindex = lines - 1;
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else
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lineindex = 0;
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@ -1008,15 +994,11 @@ heap_getnext(HeapScanDesc scan, ScanDirection direction)
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HEAPDEBUG_1; /* heap_getnext( info ) */
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/*
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* Note: we depend here on the -1/0/1 encoding of ScanDirection.
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*/
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if (scan->rs_pageatatime)
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heapgettup_pagemode(scan, (int) direction,
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heapgettup_pagemode(scan, direction,
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scan->rs_nkeys, scan->rs_key);
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else
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heapgettup(scan, (int) direction,
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scan->rs_nkeys, scan->rs_key);
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heapgettup(scan, direction, scan->rs_nkeys, scan->rs_key);
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if (scan->rs_ctup.t_data == NULL)
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{
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@ -2745,13 +2727,13 @@ heap_restrpos(HeapScanDesc scan)
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{
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scan->rs_cindex = scan->rs_mindex;
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heapgettup_pagemode(scan,
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0, /* "no movement" */
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NoMovementScanDirection,
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0, /* needn't recheck scan keys */
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NULL);
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}
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else
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heapgettup(scan,
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0, /* "no movement" */
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NoMovementScanDirection,
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0, /* needn't recheck scan keys */
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NULL);
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}
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@ -26,7 +26,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.266 2006/02/19 00:04:26 neilc Exp $
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* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.267 2006/02/21 23:01:54 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -218,7 +218,7 @@ ExecutorRun(QueryDesc *queryDesc,
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/*
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* run plan
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*/
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if (direction == NoMovementScanDirection)
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if (ScanDirectionIsNoMovement(direction))
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result = NULL;
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else
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result = ExecutePlan(estate,
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@ -8,7 +8,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.98 2005/11/22 18:17:21 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/tcop/pquery.c,v 1.99 2006/02/21 23:01:54 neilc Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -795,7 +795,7 @@ PortalRunSelect(Portal portal,
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nprocessed = queryDesc->estate->es_processed;
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}
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if (direction != NoMovementScanDirection)
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if (!ScanDirectionIsNoMovement(direction))
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{
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long oldPos;
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@ -837,7 +837,7 @@ PortalRunSelect(Portal portal,
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nprocessed = queryDesc->estate->es_processed;
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}
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if (direction != NoMovementScanDirection)
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if (!ScanDirectionIsNoMovement(direction))
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{
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if (nprocessed > 0 && portal->atEnd)
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{
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@ -890,13 +890,13 @@ RunFromStore(Portal portal, ScanDirection direction, long count,
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(*dest->rStartup) (dest, CMD_SELECT, portal->tupDesc);
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if (direction == NoMovementScanDirection)
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if (ScanDirectionIsNoMovement(direction))
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{
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/* do nothing except start/stop the destination */
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}
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else
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{
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bool forward = (direction == ForwardScanDirection);
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bool forward = ScanDirectionIsForward(direction);
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for (;;)
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{
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