From ff499613d2dd2c89b93379dbee943b8e6cee5f20 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 16 Dec 2009 22:16:16 +0000
Subject: [PATCH] Several fixes for EXPLAIN (FORMAT YAML), plus one for EXPLAIN
(FORMAT JSON).
ExplainSeparatePlans() was busted for both JSON and YAML output - the present
code is a holdover from the original version of my machine-readable explain
patch, which didn't have the grouping_stack machinery. Also, fix an odd
distribution of labor between ExplainBeginGroup() and ExplainYAMLLineStarting()
when marking lists with "- ", with each providing one character. This broke
the output format for multi-query statements. Also, fix ExplainDummyGroup()
for the YAML output format.
Along the way, make the YAML format use escape_yaml() in situations where the
JSON format uses escape_json(). Right now, it doesn't matter because all the
values are known not to need escaping, but it seems safer this way. Finally,
I added some comments to better explain what the YAML output format is doing.
Greg Sabino Mullane reported the issues with multi-query statements.
Analysis and remaining cleanups by me.
---
src/backend/commands/explain.c | 48 ++++++++++++++++++++++------------
1 file changed, 31 insertions(+), 17 deletions(-)
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index e63b8579d84..f4a6aa4e715 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994-5, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.196 2009/12/15 04:57:47 rhaas Exp $
+ * $PostgreSQL: pgsql/src/backend/commands/explain.c,v 1.197 2009/12/16 22:16:16 rhaas Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1694,10 +1694,7 @@ ExplainProperty(const char *qlabel, const char *value, bool numeric,
case EXPLAIN_FORMAT_YAML:
ExplainYAMLLineStarting(es);
appendStringInfo(es->str, "%s: ", qlabel);
- if (numeric)
- appendStringInfoString(es->str, value);
- else
- escape_yaml(es->str, value);
+ escape_yaml(es->str, value);
break;
}
}
@@ -1785,15 +1782,23 @@ ExplainOpenGroup(const char *objtype, const char *labelname,
break;
case EXPLAIN_FORMAT_YAML:
+
+ /*
+ * In YAML format, the grouping stack is an integer list. 0 means
+ * we've emitted nothing at this grouping level AND this grouping
+ * level is unlabelled and must be marked with "- ". See
+ * ExplainYAMLLineStarting().
+ */
ExplainYAMLLineStarting(es);
if (labelname)
{
- appendStringInfo(es->str, "%s:", labelname);
+ escape_yaml(es->str, labelname);
+ appendStringInfoChar(es->str, ':');
es->grouping_stack = lcons_int(1, es->grouping_stack);
}
else
{
- appendStringInfoChar(es->str, '-');
+ appendStringInfoString(es->str, "- ");
es->grouping_stack = lcons_int(0, es->grouping_stack);
}
es->indent++;
@@ -1868,8 +1873,15 @@ ExplainDummyGroup(const char *objtype, const char *labelname, ExplainState *es)
case EXPLAIN_FORMAT_YAML:
ExplainYAMLLineStarting(es);
if (labelname)
- appendStringInfo(es->str, "%s:", labelname);
- appendStringInfoString(es->str, objtype);
+ {
+ escape_yaml(es->str, labelname);
+ appendStringInfoString(es->str, ": ");
+ }
+ else
+ {
+ appendStringInfoString(es->str, "- ");
+ }
+ escape_yaml(es->str, objtype);
break;
}
}
@@ -1946,18 +1958,14 @@ ExplainSeparatePlans(ExplainState *es)
switch (es->format)
{
case EXPLAIN_FORMAT_TEXT:
- case EXPLAIN_FORMAT_YAML:
/* add a blank line */
appendStringInfoChar(es->str, '\n');
break;
case EXPLAIN_FORMAT_XML:
- /* nothing to do */
- break;
-
case EXPLAIN_FORMAT_JSON:
- /* must have a comma between array elements */
- appendStringInfoChar(es->str, ',');
+ case EXPLAIN_FORMAT_YAML:
+ /* nothing to do */
break;
}
}
@@ -2011,6 +2019,12 @@ ExplainJSONLineEnding(ExplainState *es)
/*
* Indent a YAML line.
+ *
+ * YAML lines are ordinarily indented by two spaces per indentation level.
+ * The text emitted for each property begins just prior to the preceding
+ * line-break, except for the first property in an unlabelled group, for which
+ * it begins immediately after the "- " that introduces the group. The first
+ * property of the group appears on the same line as the opening "- ".
*/
static void
ExplainYAMLLineStarting(ExplainState *es)
@@ -2018,7 +2032,6 @@ ExplainYAMLLineStarting(ExplainState *es)
Assert(es->format == EXPLAIN_FORMAT_YAML);
if (linitial_int(es->grouping_stack) == 0)
{
- appendStringInfoChar(es->str, ' ');
linitial_int(es->grouping_stack) = 1;
}
else
@@ -2074,7 +2087,8 @@ escape_json(StringInfo buf, const char *str)
}
/*
- * YAML is a superset of JSON: if we find quotable characters, we call escape_json
+ * YAML is a superset of JSON: if we find quotable characters, we call
+ * escape_json. If not, we emit the property unquoted for better readability.
*/
static void
escape_yaml(StringInfo buf, const char *str)
--
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