From 268b0952f08832fe7539b767abeaaafe8f57dec0 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Tue, 23 Oct 2012 13:34:56 +0200
Subject: [PATCH] postrr.sql: Added PostRR_update() functions.

These functions may be used to insert or update a value in an archive. The
functions expect a timestamp and double precision value as arguments to
describe the new values. The postrr.rrarchives will then be used to look up
the actual place where to store the values (there may be multiple ones).

There are currently two overloaded versions of this function. One accepts the
name of an archive and the other expects the definition of an archive as
arguments. The latter is meant to be used for internal purposes while the
other is meant to be used by the user. This is not enforced in any way, though
(and I don't see any reason to do so).
---
 src/postrr.sql.in | 72 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/src/postrr.sql.in b/src/postrr.sql.in
index 546a9df..7197726 100644
--- a/src/postrr.sql.in
+++ b/src/postrr.sql.in
@@ -302,6 +302,78 @@ CREATE OR REPLACE FUNCTION CData_update(cdata, cdata)
 	AS 'postrr-@POSTRR_MAJOR_VERSION@.@POSTRR_MINOR_VERSION@', 'cdata_update'
 	LANGUAGE 'C' IMMUTABLE;
 
+CREATE OR REPLACE FUNCTION PostRR_update(name, name, name, timestamp, double precision)
+	RETURNS cdata
+	LANGUAGE plpgsql
+	AS $$
+DECLARE
+	tbl ALIAS FOR $1;
+	tscol ALIAS FOR $2;
+	vcol ALIAS FOR $3;
+	ts ALIAS FOR $4;
+	value ALIAS FOR $5;
+	ts_str text;
+	v_str text;
+	update_qry text;
+	newts rrtimeslice;
+	new cdata;
+BEGIN
+	tscol  := quote_ident(tscol);
+	vcol   := quote_ident(vcol);
+	ts_str := quote_literal(ts);
+	v_str  := quote_literal(value);
+
+	update_qry = 'CData_update(' || vcol || ', ' || v_str || ')';
+
+	BEGIN
+		EXECUTE 'UPDATE ' || tbl
+			|| ' SET ' || tscol || ' = ' || ts_str
+			|| ', ' || vcol || ' = ' || update_qry
+			|| ' WHERE ' || tscol || ' = ' || ts_str
+			|| ' RETURNING ' || tscol || ', ' || vcol
+			INTO STRICT newts, new;
+
+		EXCEPTION
+			WHEN NO_DATA_FOUND THEN
+				EXECUTE 'INSERT INTO ' || tbl
+					|| ' (' || tscol || ', ' || vcol
+					|| ') VALUES (' || ts_str || ', ' || v_str
+					|| ') RETURNING ' || tscol || ', ' || vcol
+					INTO newts, new;
+				-- use strict again; on exception retry?
+			WHEN TOO_MANY_ROWS THEN
+				RAISE EXCEPTION '% is not unique in %.%', ts_str, tbl, tscol;
+	END;
+	RETURN new;
+END;
+$$;
+
+CREATE OR REPLACE FUNCTION PostRR_update(text, timestamp, double precision)
+	RETURNS SETOF cdata
+	LANGUAGE plpgsql
+	AS $$
+DECLARE
+	rraname ALIAS FOR $1;
+	ts ALIAS FOR $2;
+	value ALIAS FOR $3;
+	adef RECORD;
+	new cdata;
+BEGIN
+	FOR adef IN SELECT tbl, tscol, vcol FROM postrr.rrarchives
+			WHERE postrr.rrarchives.rraname = $1 LOOP
+		EXECUTE 'SELECT PostRR_update('
+			|| quote_literal(adef.tbl) || ', '
+			|| quote_literal(adef.tscol) || ', '
+			|| quote_literal(adef.vcol) || ', '
+			|| quote_literal(ts) || ', '
+			|| quote_literal(value) || ')'
+			INTO new;
+		RETURN NEXT new;
+	END LOOP;
+	RETURN;
+END;
+$$;
+
 COMMIT;
 
 SET client_min_messages TO DEFAULT;
-- 
2.30.2