diff --git a/src/bin/pg_basebackup/pg_basebackup.c b/src/bin/pg_basebackup/pg_basebackup.c
index 80dc3bbc8da..00408f1de49 100644
--- a/src/bin/pg_basebackup/pg_basebackup.c
+++ b/src/bin/pg_basebackup/pg_basebackup.c
@@ -1082,8 +1082,8 @@ CreateBackupStreamer(char *archive_name, char *spclocation,
 	inject_manifest = (format == 't' && strcmp(basedir, "-") == 0 && manifest);
 
 	/* Check whether it is a tar archive and its compression type */
-	is_tar = parse_tar_compress_algorithm(archive_name,
-										  &compressed_tar_algorithm);
+	is_tar = (parse_tar_compress_algorithm(archive_name,
+										   &compressed_tar_algorithm) > 0);
 
 	/* Is this any kind of compressed tar? */
 	is_compressed_tar = (is_tar &&
diff --git a/src/bin/pg_verifybackup/pg_verifybackup.c b/src/bin/pg_verifybackup/pg_verifybackup.c
index bd4fe635c6f..a972dae3070 100644
--- a/src/bin/pg_verifybackup/pg_verifybackup.c
+++ b/src/bin/pg_verifybackup/pg_verifybackup.c
@@ -967,8 +967,12 @@ precheck_tar_backup_file(verifier_context *context, char *relpath,
 		tblspc_oid = (Oid) num;
 	}
 
-	/* Now, check the compression type of the tar */
-	if (!parse_tar_compress_algorithm(suffix, &compress_algorithm))
+	/*
+	 * If parse_tar_compress_algorithm returns exactly 0, there are no
+	 * characters between the prefix we already checked and the detected
+	 * suffix. Any other case is unexpected.
+	 */
+	if (parse_tar_compress_algorithm(suffix, &compress_algorithm) != 0)
 	{
 		report_backup_error(context,
 							"file \"%s\" is not expected in a tar format backup",
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index c777e6763e5..d6b2a7adcbf 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -1242,7 +1242,7 @@ main(int argc, char **argv)
 	if (waldir != NULL)
 	{
 		/* Check whether the path looks like a tar archive by its extension */
-		if (parse_tar_compress_algorithm(waldir, &compression))
+		if (parse_tar_compress_algorithm(waldir, &compression) >= 0)
 		{
 			split_path(waldir, &private.archive_dir, &private.archive_name);
 		}
@@ -1286,7 +1286,8 @@ main(int argc, char **argv)
 				pg_fatal("could not open directory \"%s\": %m", waldir);
 		}
 
-		if (fname != NULL && parse_tar_compress_algorithm(fname, &compression))
+		if (fname != NULL &&
+			parse_tar_compress_algorithm(fname, &compression) >= 0)
 		{
 			private.archive_dir = waldir;
 			private.archive_name = fname;
diff --git a/src/common/compression.c b/src/common/compression.c
index ae2089d9406..e78913ad9dc 100644
--- a/src/common/compression.c
+++ b/src/common/compression.c
@@ -42,33 +42,47 @@ static bool expect_boolean_value(char *keyword, char *value,
 								 pg_compress_specification *result);
 
 /*
- * Look up a compression algorithm by archive file extension. Returns true and
- * sets *algorithm if the extension is recognized. Otherwise returns false.
+ * Look up a compression algorithm by archive file extension. Sets *algorithm
+ * and returns the length of the non-extension portion of the filename, or -1
+ * if the filename does not end with a recognized tar extension.
  */
-bool
+int
 parse_tar_compress_algorithm(const char *fname, pg_compress_algorithm *algorithm)
 {
-	size_t		fname_len = strlen(fname);
+	int			fname_len = strlen(fname);
 
 	if (fname_len >= 4 &&
 		strcmp(fname + fname_len - 4, ".tar") == 0)
+	{
 		*algorithm = PG_COMPRESSION_NONE;
+		return fname_len - 4;
+	}
 	else if (fname_len >= 4 &&
 			 strcmp(fname + fname_len - 4, ".tgz") == 0)
+	{
 		*algorithm = PG_COMPRESSION_GZIP;
+		return fname_len - 4;
+	}
 	else if (fname_len >= 7 &&
 			 strcmp(fname + fname_len - 7, ".tar.gz") == 0)
+	{
 		*algorithm = PG_COMPRESSION_GZIP;
+		return fname_len - 7;
+	}
 	else if (fname_len >= 8 &&
 			 strcmp(fname + fname_len - 8, ".tar.lz4") == 0)
+	{
 		*algorithm = PG_COMPRESSION_LZ4;
+		return fname_len - 8;
+	}
 	else if (fname_len >= 8 &&
 			 strcmp(fname + fname_len - 8, ".tar.zst") == 0)
+	{
 		*algorithm = PG_COMPRESSION_ZSTD;
-	else
-		return false;
+		return fname_len - 8;
+	}
 
-	return true;
+	return -1;
 }
 
 /*
diff --git a/src/include/common/compression.h b/src/include/common/compression.h
index f99c747cdd3..adbe668a105 100644
--- a/src/include/common/compression.h
+++ b/src/include/common/compression.h
@@ -41,7 +41,7 @@ typedef struct pg_compress_specification
 
 extern void parse_compress_options(const char *option, char **algorithm,
 								   char **detail);
-extern bool parse_tar_compress_algorithm(const char *fname,
+extern int	parse_tar_compress_algorithm(const char *fname,
 										 pg_compress_algorithm *algorithm);
 extern bool parse_compress_algorithm(char *name, pg_compress_algorithm *algorithm);
 extern const char *get_compress_algorithm_name(pg_compress_algorithm algorithm);