diff --git a/src/backend/replication/basebackup_lz4.c b/src/backend/replication/basebackup_lz4.c
index d26032783c..472b620d7c 100644
--- a/src/backend/replication/basebackup_lz4.c
+++ b/src/backend/replication/basebackup_lz4.c
@@ -193,7 +193,7 @@ bbsink_lz4_archive_contents(bbsink *sink, size_t avail_in)
 	 * LZ4F_compressBound(), ask the next sink to process the data so that we
 	 * can empty the buffer.
 	 */
-	if ((mysink->base.bbs_next->bbs_buffer_length - mysink->bytes_written) <=
+	if ((mysink->base.bbs_next->bbs_buffer_length - mysink->bytes_written) <
 		avail_in_bound)
 	{
 		bbsink_archive_contents(sink->bbs_next, mysink->bytes_written);
@@ -238,7 +238,7 @@ bbsink_lz4_end_archive(bbsink *sink)
 
 	Assert(mysink->base.bbs_next->bbs_buffer_length >= lz4_footer_bound);
 
-	if ((mysink->base.bbs_next->bbs_buffer_length - mysink->bytes_written) <=
+	if ((mysink->base.bbs_next->bbs_buffer_length - mysink->bytes_written) <
 		lz4_footer_bound)
 	{
 		bbsink_archive_contents(sink->bbs_next, mysink->bytes_written);
diff --git a/src/bin/pg_basebackup/bbstreamer_lz4.c b/src/bin/pg_basebackup/bbstreamer_lz4.c
index f0bc226bf8..bde018246f 100644
--- a/src/bin/pg_basebackup/bbstreamer_lz4.c
+++ b/src/bin/pg_basebackup/bbstreamer_lz4.c
@@ -99,7 +99,7 @@ bbstreamer_lz4_compressor_new(bbstreamer *next, int compresslevel)
 	compressed_bound = LZ4F_compressBound(streamer->base.bbs_buffer.maxlen, prefs);
 
 	/* Enlarge buffer if it falls short of compression bound. */
-	if (streamer->base.bbs_buffer.maxlen <= compressed_bound)
+	if (streamer->base.bbs_buffer.maxlen < compressed_bound)
 		enlargeStringInfo(&streamer->base.bbs_buffer, compressed_bound);
 
 	ctxError = LZ4F_createCompressionContext(&streamer->cctx, LZ4F_VERSION);
@@ -170,7 +170,7 @@ bbstreamer_lz4_compressor_content(bbstreamer *streamer,
 	 */
 	out_bound = LZ4F_compressBound(len, &mystreamer->prefs);
 	Assert(mystreamer->base.bbs_buffer.maxlen >= out_bound);
-	if (avail_out <= out_bound)
+	if (avail_out < out_bound)
 	{
 			bbstreamer_content(mystreamer->base.bbs_next, member,
 							   mystreamer->base.bbs_buffer.data,
@@ -218,7 +218,7 @@ bbstreamer_lz4_compressor_finalize(bbstreamer *streamer)
 	/* Find out the footer bound and update the output buffer. */
 	footer_bound = LZ4F_compressBound(0, &mystreamer->prefs);
 	Assert(mystreamer->base.bbs_buffer.maxlen >= footer_bound);
-	if ((mystreamer->base.bbs_buffer.maxlen - mystreamer->bytes_written) <=
+	if ((mystreamer->base.bbs_buffer.maxlen - mystreamer->bytes_written) <
 		footer_bound)
 	{
 			bbstreamer_content(mystreamer->base.bbs_next, NULL,