From ed9e450571d728b7e0ea53b5d04e29169ab86f73 Mon Sep 17 00:00:00 2001
From: Andrew Kane <andrew@ankane.org>
Date: Sun, 3 Sep 2023 17:06:22 -0700
Subject: [PATCH] Copy index tuple

---
 src/ivfflat.h |  1 +
 src/ivfscan.c | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/src/ivfflat.h b/src/ivfflat.h
index ef44a6c..10a51c8 100644
--- a/src/ivfflat.h
+++ b/src/ivfflat.h
@@ -248,6 +248,7 @@ typedef struct IvfflatScanOpaqueData
 	bool		first;
 	Buffer		buf;
 	ItemPointerData heaptid;
+	IndexTuple	itup;
 
 	/* Sorting */
 	Tuplesortstate *sortstate;
diff --git a/src/ivfscan.c b/src/ivfscan.c
index 29a822b..bead69b 100644
--- a/src/ivfscan.c
+++ b/src/ivfscan.c
@@ -266,6 +266,7 @@ ivfflatbeginscan(Relation index, int nkeys, int norderbys)
 	so->buf = InvalidBuffer;
 	so->first = true;
 	ItemPointerSetInvalid(&so->heaptid);
+	so->itup = NULL;
 	so->probes = probes;
 	so->dimensions = dimensions;
 
@@ -410,12 +411,22 @@ ivfflatgettuple(IndexScanDesc scan, ScanDirection dir)
 		if (scan->xs_want_itup)
 		{
 			Page		page;
+			OffsetNumber offno;
+			IndexTuple	itup;
+			Size		itupSize;
 
 			LockBuffer(so->buf, BUFFER_LOCK_SHARE);
 			page = BufferGetPage(so->buf);
+			offno = ItemPointerGetOffsetNumber(indextid);
+			itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, offno));
+			itupSize = IndexTupleSize(itup);
 
-			/* TODO Copy tuple to IvfflatScanOpaque */
-			scan->xs_itup = (IndexTuple) PageGetItem(page, PageGetItemId(page, ItemPointerGetOffsetNumber(indextid)));
+			if (so->itup == NULL)
+				so->itup = palloc(BLCKSZ);
+
+			memcpy(so->itup, itup, itupSize);
+
+			scan->xs_itup = so->itup;
 
 			LockBuffer(so->buf, BUFFER_LOCK_UNLOCK);
 		}
@@ -439,6 +450,9 @@ ivfflatendscan(IndexScanDesc scan)
 	if (BufferIsValid(so->buf))
 		ReleaseBuffer(so->buf);
 
+	if (so->itup != NULL)
+		pfree(so->itup);
+
 	pairingheap_free(so->listQueue);
 	tuplesort_end(so->sortstate);