diff --git a/src/bin/pg_dump/compress_gzip.c b/src/bin/pg_dump/compress_gzip.c
index d9c3969332..cec0b41fce 100644
--- a/src/bin/pg_dump/compress_gzip.c
+++ b/src/bin/pg_dump/compress_gzip.c
@@ -120,8 +120,8 @@ WriteDataToArchiveGzip(ArchiveHandle *AH, CompressorState *cs,
 		 * actually allocate one extra byte because some routines want to
 		 * append a trailing zero byte to the zlib output.
 		 */
-		gzipcs->outbuf = pg_malloc(ZLIB_OUT_SIZE + 1);
-		gzipcs->outsize = ZLIB_OUT_SIZE;
+		gzipcs->outsize = DEFAULT_IO_BUFFER_SIZE;
+		gzipcs->outbuf = pg_malloc(gzipcs->outsize + 1);
 
 		/*
 		 * A level of zero simply copies the input one block at the time. This
@@ -158,10 +158,10 @@ ReadDataFromArchiveGzip(ArchiveHandle *AH, CompressorState *cs)
 	zp->zfree = Z_NULL;
 	zp->opaque = Z_NULL;
 
-	buf = pg_malloc(ZLIB_IN_SIZE);
-	buflen = ZLIB_IN_SIZE;
+	buflen = DEFAULT_IO_BUFFER_SIZE;
+	buf = pg_malloc(buflen);
 
-	out = pg_malloc(ZLIB_OUT_SIZE + 1);
+	out = pg_malloc(DEFAULT_IO_BUFFER_SIZE + 1);
 
 	if (inflateInit(zp) != Z_OK)
 		pg_fatal("could not initialize compression library: %s",
@@ -176,14 +176,14 @@ ReadDataFromArchiveGzip(ArchiveHandle *AH, CompressorState *cs)
 		while (zp->avail_in > 0)
 		{
 			zp->next_out = (void *) out;
-			zp->avail_out = ZLIB_OUT_SIZE;
+			zp->avail_out = DEFAULT_IO_BUFFER_SIZE;
 
 			res = inflate(zp, 0);
 			if (res != Z_OK && res != Z_STREAM_END)
 				pg_fatal("could not uncompress data: %s", zp->msg);
 
-			out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
-			ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
+			out[DEFAULT_IO_BUFFER_SIZE - zp->avail_out] = '\0';
+			ahwrite(out, 1, DEFAULT_IO_BUFFER_SIZE - zp->avail_out, AH);
 		}
 	}
 
@@ -192,13 +192,13 @@ ReadDataFromArchiveGzip(ArchiveHandle *AH, CompressorState *cs)
 	while (res != Z_STREAM_END)
 	{
 		zp->next_out = (void *) out;
-		zp->avail_out = ZLIB_OUT_SIZE;
+		zp->avail_out = DEFAULT_IO_BUFFER_SIZE;
 		res = inflate(zp, 0);
 		if (res != Z_OK && res != Z_STREAM_END)
 			pg_fatal("could not uncompress data: %s", zp->msg);
 
-		out[ZLIB_OUT_SIZE - zp->avail_out] = '\0';
-		ahwrite(out, 1, ZLIB_OUT_SIZE - zp->avail_out, AH);
+		out[DEFAULT_IO_BUFFER_SIZE - zp->avail_out] = '\0';
+		ahwrite(out, 1, DEFAULT_IO_BUFFER_SIZE - zp->avail_out, AH);
 	}
 
 	if (inflateEnd(zp) != Z_OK)
diff --git a/src/bin/pg_dump/compress_io.h b/src/bin/pg_dump/compress_io.h
index 7c2f9b5668..fd8752db0d 100644
--- a/src/bin/pg_dump/compress_io.h
+++ b/src/bin/pg_dump/compress_io.h
@@ -17,9 +17,8 @@
 
 #include "pg_backup_archiver.h"
 
-/* Initial buffer sizes used in zlib compression. */
-#define ZLIB_OUT_SIZE	4096
-#define ZLIB_IN_SIZE	4096
+/* Default size used for IO buffers */
+#define DEFAULT_IO_BUFFER_SIZE	4096
 
 extern char *supports_compression(const pg_compress_specification compression_spec);
 
diff --git a/src/bin/pg_dump/compress_lz4.c b/src/bin/pg_dump/compress_lz4.c
index 278f262162..2f3e552f51 100644
--- a/src/bin/pg_dump/compress_lz4.c
+++ b/src/bin/pg_dump/compress_lz4.c
@@ -20,9 +20,6 @@
 #include <lz4.h>
 #include <lz4frame.h>
 
-#define LZ4_OUT_SIZE	(4 * 1024)
-#define LZ4_IN_SIZE		(16 * 1024)
-
 /*
  * LZ4F_HEADER_SIZE_MAX first appeared in v1.7.5 of the library.
  * Redefine it for installations with a lesser version.
@@ -57,7 +54,7 @@ ReadDataFromArchiveLZ4(ArchiveHandle *AH, CompressorState *cs)
 	size_t		buflen;
 	size_t		cnt;
 
-	buflen = LZ4_IN_SIZE;
+	buflen = DEFAULT_IO_BUFFER_SIZE;
 	buf = pg_malloc(buflen);
 	decbuf = pg_malloc(buflen);
 
@@ -208,7 +205,7 @@ LZ4File_init(LZ4File *fs, int size, bool compressing)
 
 	if (fs->compressing)
 	{
-		fs->buflen = LZ4F_compressBound(LZ4_IN_SIZE, &fs->prefs);
+		fs->buflen = LZ4F_compressBound(DEFAULT_IO_BUFFER_SIZE, &fs->prefs);
 		if (fs->buflen < LZ4F_HEADER_SIZE_MAX)
 			fs->buflen = LZ4F_HEADER_SIZE_MAX;
 
@@ -244,7 +241,7 @@ LZ4File_init(LZ4File *fs, int size, bool compressing)
 			return false;
 		}
 
-		fs->buflen = size > LZ4_OUT_SIZE ? size : LZ4_OUT_SIZE;
+		fs->buflen = Max(size, DEFAULT_IO_BUFFER_SIZE);
 		fs->buffer = pg_malloc(fs->buflen);
 
 		fs->overflowalloclen = fs->buflen;
@@ -423,7 +420,7 @@ LZ4File_write(const void *ptr, size_t size, CompressFileHandle *CFH)
 
 	while (remaining > 0)
 	{
-		int			chunk = remaining < LZ4_IN_SIZE ? remaining : LZ4_IN_SIZE;
+		int			chunk = Min(remaining, DEFAULT_IO_BUFFER_SIZE);
 
 		remaining -= chunk;
 
diff --git a/src/bin/pg_dump/compress_none.c b/src/bin/pg_dump/compress_none.c
index 18f3514d11..736a7957bc 100644
--- a/src/bin/pg_dump/compress_none.c
+++ b/src/bin/pg_dump/compress_none.c
@@ -33,8 +33,8 @@ ReadDataFromArchiveNone(ArchiveHandle *AH, CompressorState *cs)
 	char	   *buf;
 	size_t		buflen;
 
-	buf = pg_malloc(ZLIB_OUT_SIZE);
-	buflen = ZLIB_OUT_SIZE;
+	buflen = DEFAULT_IO_BUFFER_SIZE;
+	buf = pg_malloc(buflen);
 
 	while ((cnt = cs->readF(AH, &buf, &buflen)))
 	{
diff --git a/src/bin/pg_dump/pg_backup_directory.c b/src/bin/pg_dump/pg_backup_directory.c
index 525dbf9bf0..abaaa3b10e 100644
--- a/src/bin/pg_dump/pg_backup_directory.c
+++ b/src/bin/pg_dump/pg_backup_directory.c
@@ -394,8 +394,8 @@ _PrintFileData(ArchiveHandle *AH, char *filename)
 	if (!CFH)
 		pg_fatal("could not open input file \"%s\": %m", filename);
 
-	buf = pg_malloc(ZLIB_OUT_SIZE);
-	buflen = ZLIB_OUT_SIZE;
+	buflen = DEFAULT_IO_BUFFER_SIZE;
+	buf = pg_malloc(buflen);
 
 	while (CFH->read_func(buf, buflen, &cnt, CFH) && cnt > 0)
 	{