Add second pass (reversed) from gettuple if we did not found enough tuples

feodor · feodor · commit 1a4070e2cd95 · 2016-08-30T18:02:54.000+03:00
diff --git a/rum.h b/rum.h
@@ -695,6 +695,7 @@ typedef struct RumScanOpaqueData
 	TIDBitmap  *tbm;
 
 	ScanDirection	naturalOrder;
+	bool			secondPass;
 }	RumScanOpaqueData;
 
 typedef RumScanOpaqueData *RumScanOpaque;
@@ -706,6 +707,7 @@ extern void rumrescan(IndexScanDesc scan, ScanKey scankey, int nscankeys,
 extern Datum rummarkpos(PG_FUNCTION_ARGS);
 extern Datum rumrestrpos(PG_FUNCTION_ARGS);
 extern void rumNewScanKey(IndexScanDesc scan);
+extern void freeScanKeys(RumScanOpaque so);
 
 /* rumget.c */
 extern int64 rumgetbitmap(IndexScanDesc scan, TIDBitmap *tbm);
diff --git a/rumget.c b/rumget.c
@@ -25,15 +25,6 @@
 /* GUC parameter */
 int			RumFuzzySearchLimit = 0;
 
-typedef struct pendingPosition
-{
-	Buffer		pendingBuffer;
-	OffsetNumber firstOffset;
-	OffsetNumber lastOffset;
-	ItemPointerData item;
-	bool	   *hasMatchKey;
-} pendingPosition;
-
 static bool scanPage(RumState * rumstate, RumScanEntry entry, RumKey *item,
 		 Page page, bool equalOk);
 static void insertScanItem(RumScanOpaque so, bool recheck);
@@ -2331,6 +2322,34 @@ insertScanItem(RumScanOpaque so, bool recheck)
 	rum_tuplesort_putrum(so->sortstate, item);
 }
 
+static void
+reverseScan(IndexScanDesc scan)
+{
+	RumScanOpaque	so = (RumScanOpaque) scan->opaque;
+	int				i, j;
+
+	freeScanKeys(so);
+	rumNewScanKey(scan);
+
+	for(i=0; i<so->nkeys; i++)
+	{
+		RumScanKey	key = so->keys[i];
+
+		key->isFinished = false;
+		key->scanDirection = - key->scanDirection;
+
+		for(j=0; j<key->nentries; j++)
+		{
+			RumScanEntry	entry = key->scanEntry[j];
+
+			entry->isFinished = false;
+			entry->scanDirection = - entry->scanDirection;
+		}
+	}
+
+	startScan(scan);
+}
+
 bool
 rumgettuple(IndexScanDesc scan, ScanDirection direction)
 {
@@ -2341,8 +2360,6 @@ rumgettuple(IndexScanDesc scan, ScanDirection direction)
 
 	if (so->firstCall)
 	{
-		so->norderbys = scan->numberOfOrderBys;
-
 		/*
 		 * Set up the scan keys, and check for unsatisfiable query.
 		 */
@@ -2352,10 +2369,6 @@ rumgettuple(IndexScanDesc scan, ScanDirection direction)
 		if (RumIsVoidRes(scan))
 			PG_RETURN_INT64(0);
 
-		so->tbm = NULL;
-		so->entriesIncrIndex = -1;
-		so->firstCall = false;
-
 		startScan(scan);
 		if (so->naturalOrder == NoMovementScanDirection)
 		{
@@ -2384,6 +2397,12 @@ rumgettuple(IndexScanDesc scan, ScanDirection direction)
 
 			return true;
 		}
+		else if (so->secondPass == false)
+		{
+			reverseScan(scan);
+			so->secondPass = true;
+			return rumgettuple(scan, direction);
+		}
 
 		return false;
 	}
diff --git a/rumscan.c b/rumscan.c
@@ -285,7 +285,7 @@ freeScanEntries(RumScanEntry *entries, uint32 nentries)
 	}
 }
 
-static void
+void
 freeScanKeys(RumScanOpaque so)
 {
 	freeScanEntries(so->entries, so->totalentries);
@@ -513,6 +513,11 @@ rumNewScanKey(IndexScanDesc scan)
 	}		hasAddOnFilter = haofNone;
 
 	so->naturalOrder = NoMovementScanDirection;
+	so->secondPass = false;
+	so->tbm = NULL;
+	so->entriesIncrIndex = -1;
+	so->firstCall = false;
+	so->norderbys = scan->numberOfOrderBys;
 
 	/*
 	 * Allocate all the scan key information in the key context. (If

Original file line number	Diff line number	Diff line change
`@@ -285,7 +285,7 @@ freeScanEntries(RumScanEntry *entries, uint32 nentries)`
`285`	`285`	`}`
`286`	`286`	`}`
`287`	`287`
`288`		`-static void`
	`288`	`+void`
`289`	`289`	`freeScanKeys(RumScanOpaque so)`
`290`	`290`	`{`
`291`	`291`	`freeScanEntries(so->entries, so->totalentries);`
`@@ -513,6 +513,11 @@ rumNewScanKey(IndexScanDesc scan)`
`513`	`513`	`} hasAddOnFilter = haofNone;`
`514`	`514`
`515`	`515`	`so->naturalOrder = NoMovementScanDirection;`
	`516`	`+ so->secondPass = false;`
	`517`	`+ so->tbm = NULL;`
	`518`	`+ so->entriesIncrIndex = -1;`
	`519`	`+ so->firstCall = false;`
	`520`	`+ so->norderbys = scan->numberOfOrderBys;`
`516`	`521`
`517`	`522`	`/*`
`518`	`523`	`* Allocate all the scan key information in the key context. (If`