1 files changed, 130 insertions, 0 deletions
diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index e7452af6790..dff1e7685e9 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -200,3 +200,133 @@ xlog_identify(uint8 info)
 
 	return id;
 }
+
+/*
+ * Returns a string giving information about all the blocks in an
+ * XLogRecord.
+ */
+void
+XLogRecGetBlockRefInfo(XLogReaderState *record, bool pretty,
+					   bool detailed_format, StringInfo buf,
+					   uint32 *fpi_len)
+{
+	int	block_id;
+
+	Assert(record != NULL);
+
+	if (detailed_format && pretty)
+		appendStringInfoChar(buf, '\n');
+
+	for (block_id = 0; block_id <= XLogRecMaxBlockId(record); block_id++)
+	{
+		RelFileNode rnode = {InvalidOid, InvalidOid, InvalidOid};
+		ForkNumber	forknum = InvalidForkNumber;
+		BlockNumber blk = InvalidBlockNumber;
+
+		if (!XLogRecHasBlockRef(record, block_id))
+			continue;
+
+		XLogRecGetBlockTag(record, block_id, &rnode, &forknum, &blk);
+
+		if (detailed_format)
+		{
+			/* Get block references in detailed format. */
+
+			if (pretty)
+				appendStringInfoChar(buf, '\t');
+			else if (block_id > 0)
+				appendStringInfoChar(buf, ' ');
+
+			appendStringInfo(buf,
+							 "blkref #%d: rel %u/%u/%u fork %s blk %u",
+							 block_id,
+							 rnode.spcNode, rnode.dbNode, rnode.relNode,
+							 forkNames[forknum],
+							 blk);
+
+			if (XLogRecHasBlockImage(record, block_id))
+			{
+				uint8		bimg_info = XLogRecGetBlock(record, block_id)->bimg_info;
+
+				/* Calculate the amount of FPI data in the record. */
+				if (fpi_len)
+					*fpi_len += XLogRecGetBlock(record, block_id)->bimg_len;
+
+				if (BKPIMAGE_COMPRESSED(bimg_info))
+				{
+					const char *method;
+
+					if ((bimg_info & BKPIMAGE_COMPRESS_PGLZ) != 0)
+						method = "pglz";
+					else if ((bimg_info & BKPIMAGE_COMPRESS_LZ4) != 0)
+						method = "lz4";
+					else if ((bimg_info & BKPIMAGE_COMPRESS_ZSTD) != 0)
+						method = "zstd";
+					else
+						method = "unknown";
+
+					appendStringInfo(buf,
+									 " (FPW%s); hole: offset: %u, length: %u, "
+									 "compression saved: %u, method: %s",
+									 XLogRecBlockImageApply(record, block_id) ?
+									 "" : " for WAL verification",
+									 XLogRecGetBlock(record, block_id)->hole_offset,
+									 XLogRecGetBlock(record, block_id)->hole_length,
+									 BLCKSZ -
+									 XLogRecGetBlock(record, block_id)->hole_length -
+									 XLogRecGetBlock(record, block_id)->bimg_len,
+									 method);
+				}
+				else
+				{
+					appendStringInfo(buf,
+									 " (FPW%s); hole: offset: %u, length: %u",
+									 XLogRecBlockImageApply(record, block_id) ?
+									 "" : " for WAL verification",
+									 XLogRecGetBlock(record, block_id)->hole_offset,
+									 XLogRecGetBlock(record, block_id)->hole_length);
+				}
+			}
+
+			if (pretty)
+				appendStringInfoChar(buf, '\n');
+		}
+		else
+		{
+			/* Get block references in short format. */
+
+			if (forknum != MAIN_FORKNUM)
+			{
+				appendStringInfo(buf,
+								 ", blkref #%d: rel %u/%u/%u fork %s blk %u",
+								 block_id,
+								 rnode.spcNode, rnode.dbNode, rnode.relNode,
+								 forkNames[forknum],
+								 blk);
+			}
+			else
+			{
+				appendStringInfo(buf,
+								 ", blkref #%d: rel %u/%u/%u blk %u",
+								 block_id,
+								 rnode.spcNode, rnode.dbNode, rnode.relNode,
+								 blk);
+			}
+
+			if (XLogRecHasBlockImage(record, block_id))
+			{
+				/* Calculate the amount of FPI data in the record. */
+				if (fpi_len)
+					*fpi_len += XLogRecGetBlock(record, block_id)->bimg_len;
+
+				if (XLogRecBlockImageApply(record, block_id))
+					appendStringInfo(buf, " FPW");
+				else
+					appendStringInfo(buf, " FPW for WAL verification");
+			}
+		}
+	}
+
+	if (!detailed_format && pretty)
+		appendStringInfoChar(buf, '\n');
+}