diff --git a/src/bin/pg_basebackup/bbstreamer_lz4.c b/src/bin/pg_basebackup/bbstreamer_lz4.c
index 67f841d96a..2ffe2241b4 100644
--- a/src/bin/pg_basebackup/bbstreamer_lz4.c
+++ b/src/bin/pg_basebackup/bbstreamer_lz4.c
@@ -73,7 +73,6 @@ bbstreamer_lz4_compressor_new(bbstreamer *next, bc_specification *compress)
 	bbstreamer_lz4_frame   *streamer;
 	LZ4F_errorCode_t		ctxError;
 	LZ4F_preferences_t	   *prefs;
-	size_t					compressed_bound;
 
 	Assert(next != NULL);
 
@@ -92,17 +91,6 @@ bbstreamer_lz4_compressor_new(bbstreamer *next, bc_specification *compress)
 	if ((compress->options & BACKUP_COMPRESSION_OPTION_LEVEL) != 0)
 		prefs->compressionLevel = compress->level;
 
-	/*
-	 * Find out the compression bound, it specifies the minimum destination
-	 * capacity required in worst case for the success of compression operation
-	 * (LZ4F_compressUpdate) based on a given source size and preferences.
-	 */
-	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)
-		enlargeStringInfo(&streamer->base.bbs_buffer, compressed_bound);
-
 	ctxError = LZ4F_createCompressionContext(&streamer->cctx, LZ4F_VERSION);
 	if (LZ4F_isError(ctxError))
 			pg_log_error("could not create lz4 compression context: %s",
@@ -170,7 +158,6 @@ bbstreamer_lz4_compressor_content(bbstreamer *streamer,
 	 * forward the content to next streamer and empty the buffer.
 	 */
 	out_bound = LZ4F_compressBound(len, &mystreamer->prefs);
-	Assert(mystreamer->base.bbs_buffer.maxlen >= out_bound);
 	if (avail_out < out_bound)
 	{
 			bbstreamer_content(mystreamer->base.bbs_next, member,
@@ -178,6 +165,10 @@ bbstreamer_lz4_compressor_content(bbstreamer *streamer,
 							   mystreamer->bytes_written,
 							   context);
 
+			/* Enlarge buffer if it falls short of out bound. */
+			if (mystreamer->base.bbs_buffer.maxlen < out_bound)
+				enlargeStringInfo(&mystreamer->base.bbs_buffer, out_bound);
+
 			avail_out = mystreamer->base.bbs_buffer.maxlen;
 			mystreamer->bytes_written = 0;
 			next_out = (uint8 *) mystreamer->base.bbs_buffer.data;
@@ -218,7 +209,6 @@ 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) <
 		footer_bound)
 	{
@@ -227,6 +217,10 @@ bbstreamer_lz4_compressor_finalize(bbstreamer *streamer)
 							   mystreamer->bytes_written,
 							   BBSTREAMER_UNKNOWN);
 
+			/* Enlarge buffer if it falls short of footer bound. */
+			if (mystreamer->base.bbs_buffer.maxlen < footer_bound)
+				enlargeStringInfo(&mystreamer->base.bbs_buffer, footer_bound);
+
 			avail_out = mystreamer->base.bbs_buffer.maxlen;
 			mystreamer->bytes_written = 0;
 			next_out = (uint8 *) mystreamer->base.bbs_buffer.data;