sstable: fix compaction iterator bug with prefix replacement

The sstable compaction iterators stop when the key exceeds
`vState.upper`; however this is incorrect when we replace prefixes
(the key has the content prefix and `vState.upper` has the synthetic
prefix).

Switch to using `i.upper` which is in the "content prefix space" and
was already calculated at initialization.

data_test.go

@@ -510,6 +510,11 @@ func runBuildRemoteCmd(td *datadriven.TestData, d *DB, storage remote.Storage) e
 	}
 
 	writeOpts := d.opts.MakeWriterOptions(0 /* level */, tableFormat)
+	if rand.Intn(4) == 0 {
+		// Force two-level indexes.
+		writeOpts.BlockSize = 5
+		writeOpts.IndexBlockSize = 5
+	}
 
 	f, err := storage.CreateObject(path)
 	if err != nil {

sstable/reader_iter.go

@@ -280,9 +280,10 @@ func (i *compactionIterator) skipForward(
 	*i.bytesIterated += uint64(curOffset - i.prevOffset)
 	i.prevOffset = curOffset
 
-	if i.vState != nil && key != nil {
-		cmp := i.cmp(key.UserKey, i.vState.upper.UserKey)
-		if cmp > 0 || (i.vState.upper.IsExclusiveSentinel() && cmp == 0) {
+	// We have an upper bound when the table is virtual.
+	if i.upper != nil && key != nil {
+		cmp := i.cmp(key.UserKey, i.upper)
+		if cmp > 0 || (!i.endKeyInclusive && cmp == 0) {
 			return nil, base.LazyValue{}
 		}
 	}

sstable/reader_iter_two_lvl.go

@@ -1113,9 +1113,10 @@ func (i *twoLevelCompactionIterator) skipForward(
 	*i.bytesIterated += uint64(curOffset - i.prevOffset)
 	i.prevOffset = curOffset
 
-	if i.vState != nil && key != nil {
-		cmp := i.cmp(key.UserKey, i.vState.upper.UserKey)
-		if cmp > 0 || (i.vState.upper.IsExclusiveSentinel() && cmp == 0) {
+	// We have an upper bound when the table is virtual.
+	if i.upper != nil && key != nil {
+		cmp := i.cmp(key.UserKey, i.upper)
+		if cmp > 0 || (!i.endKeyInclusive && cmp == 0) {
 			return nil, base.LazyValue{}
 		}
 	}

testdata/ingest_external

@@ -418,3 +418,65 @@ iter
 seek-lt de
 ----
 a1: (foo, .)
+
+
+# Test compactions with synthetic prefix.
+reset
+----
+
+build-remote ext
+set ax ax
+set da da
+set db db
+set dc dc
+set ux ux
+----
+
+# Replace prefix with one greater than the original one.
+ingest-external prefix-replace=(d,e)
+ext,10,ea,ed
+----
+
+# Replace prefix with one smaller than the original one.
+ingest-external prefix-replace=(d,b)
+ext,10,ba,bd
+----
+
+# Write some keys so we actually perform a compaction.
+batch
+set a a
+set c c
+set f f
+----
+
+compact a z
+----
+
+lsm
+----
+6:
+  000008:[a#0,SET-f#0,SET]
+
+# Make sure we see both ba..bc and ea..ec.
+iter
+first
+next
+next
+next
+next
+next
+next
+next
+next
+next
+----
+a: (a, .)
+ba: (da, .)
+bb: (db, .)
+bc: (dc, .)
+c: (c, .)
+ea: (da, .)
+eb: (db, .)
+ec: (dc, .)
+f: (f, .)
+.