Improve the description of XLOG_RUNNING_XACTS.

Amit Kapila · Amit Kapila · commit 568546f7e46a · 2022-11-02T10:06:55.000+05:30
Previously, the description of XLOG_RUNNING_XACTS showed only top-transaction XIDs and whether subtransactions overflowed. This commit improves it to show individual subtransaction XIDs. This also improves the description of overflowed subtransactions. This additional information can be helpful for testing and debugging purposes. Author: Masahiko Sawada Reviewd by: Fujii Masao, Kyotaro Horiguchi, Ashutosh Bapat, Bharath Rupireddy Discussion: https://postgr.es/m/CAD21AoAqvaE+XEeXHHPdAGQPcCoGXxuoeutq_nWhUSQvTt5+tA@mail.gmail.com
diff --git a/src/backend/access/rmgrdesc/standbydesc.c b/src/backend/access/rmgrdesc/standbydesc.c
@@ -33,7 +33,14 @@ standby_desc_running_xacts(StringInfo buf, xl_running_xacts *xlrec)
 	}
 
 	if (xlrec->subxid_overflow)
-		appendStringInfoString(buf, "; subxid ovf");
+		appendStringInfoString(buf, "; subxid overflowed");
+
+	if (xlrec->subxcnt > 0)
+	{
+		appendStringInfo(buf, "; %d subxacts:", xlrec->subxcnt);
+		for (i = 0; i < xlrec->subxcnt; i++)
+			appendStringInfo(buf, " %u", xlrec->xids[xlrec->xcnt + i]);
+	}
 }
 
 void

Original file line number	Diff line number	Diff line change
`@@ -33,7 +33,14 @@ standby_desc_running_xacts(StringInfo buf, xl_running_xacts *xlrec)`
`33`	`33`	`}`
`34`	`34`
`35`	`35`	`if (xlrec->subxid_overflow)`
`36`		`- appendStringInfoString(buf, "; subxid ovf");`
	`36`	`+ appendStringInfoString(buf, "; subxid overflowed");`
	`37`	`+`
	`38`	`+ if (xlrec->subxcnt > 0)`
	`39`	`+ {`
	`40`	`+ appendStringInfo(buf, "; %d subxacts:", xlrec->subxcnt);`
	`41`	`+ for (i = 0; i < xlrec->subxcnt; i++)`
	`42`	`+ appendStringInfo(buf, " %u", xlrec->xids[xlrec->xcnt + i]);`
	`43`	`+ }`
`37`	`44`	`}`
`38`	`45`
`39`	`46`	`void`