Added max_probes option [skip ci]

src/ivfflat.c

@@ -17,6 +17,7 @@
 #endif
 
 int			ivfflat_probes;
+int			ivfflat_max_probes;
 bool		ivfflat_streaming;
 static relopt_kind ivfflat_relopt_kind;
 
@@ -34,6 +35,10 @@ IvfflatInit(void)
 							"Valid range is 1..lists.", &ivfflat_probes,
 							IVFFLAT_DEFAULT_PROBES, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);
 
+	DefineCustomIntVariable("ivfflat.max_probes", "Sets the max number of probes for iterative scans",
+							NULL, &ivfflat_max_probes,
+							-1, IVFFLAT_MIN_LISTS, IVFFLAT_MAX_LISTS, PGC_USERSET, 0, NULL, NULL, NULL);
+
 	DefineCustomBoolVariable("ivfflat.streaming", "Use streaming mode",
 							 NULL, &ivfflat_streaming,
 							 IVFFLAT_DEFAULT_STREAMING, PGC_USERSET, 0, NULL, NULL, NULL);

src/ivfflat.h

@@ -81,6 +81,7 @@
 
 /* Variables */
 extern int	ivfflat_probes;
+extern int	ivfflat_max_probes;
 extern bool ivfflat_streaming;
 
 typedef struct VectorArrayData

src/ivfscan.c

@@ -262,7 +262,15 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
 	if (probes > lists)
 		probes = lists;
 
-	maxProbes = ivfflat_streaming ? lists : probes;
+	if (ivfflat_streaming)
+	{
+		if (ivfflat_max_probes == -1)
+			maxProbes = lists;
+		else
+			maxProbes = ivfflat_max_probes;
+	}
+	else
+		maxProbes = probes;
 
 	so = (IvfflatScanOpaque) palloc(offsetof(IvfflatScanOpaqueData, lists) + maxProbes * sizeof(IvfflatScanList));
 	so->typeInfo = IvfflatGetTypeInfo(index);