PostRR_update(): Fixed handling of multiple columns in the same table.

[postrr.git] / src / postrr.sql.in

diff --git a/src/postrr.sql.in b/src/postrr.sql.in
index eb197452a5ca6e1e4a771398854efc0d0d625975..a3bff336ae94ef5288b4ab927a7a3c4704359d83 100644 (file)
--- a/src/postrr.sql.in
+++ b/src/postrr.sql.in
@@ -342,43 +342,47 @@ BEGIN
 
        -- XXX: handle race conditions
 
-       BEGIN
-               EXECUTE 'SELECT rrtimeslice_cmp(' || tscol || ', ' || ts_str
-                       || ') AS status FROM ' || tbl
-                       || ' WHERE ' || tscol || ' = ' || ts_str
-                       INTO STRICT status;
-
-               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?
-                               RETURN new;
-                       WHEN TOO_MANY_ROWS THEN
-                               RAISE EXCEPTION '% is not unique in %.%', ts_str, tbl, tscol;
-       END;
-
-       IF status = 0 THEN
-               -- timestamps match
-               EXECUTE 'UPDATE ' || tbl
-                       || ' SET ' || vcol || ' = ' || update_qry
-                       || ' WHERE ' || tscol || ' = ' || ts_str
-                       || ' RETURNING ' || tscol || ', ' || vcol
-                       INTO STRICT newts, new;
-       ELSIF status < 0 THEN
-               -- given timestamp is newer than in the database
-               EXECUTE 'UPDATE ' || tbl
-                       || ' SET ' || tscol || ' = ' || ts_str
-                       || ', ' || vcol || ' = ' || v_str
-                       || ' WHERE ' || tscol || ' = ' || ts_str
-                       || ' RETURNING ' || tscol || ', ' || vcol
-                       INTO STRICT newts, new;
-       ELSE
-               RAISE EXCEPTION '% is too old in %.%', ts_str, tbl, tscol;
-       END IF;
+       LOOP
+               BEGIN
+                       -- removing matching (by sequence no) old entries
+                       EXECUTE 'DELETE FROM ' || tbl
+                               || ' WHERE rrtimeslice_cmp(' || tscol || ', ' || ts_str
+                               || ') = -1; '
+                               || 'SELECT rrtimeslice_cmp(' || tscol || ', ' || ts_str
+                               || ') AS status FROM ' || tbl
+                               || ' WHERE ' || tscol || ' = ' || ts_str
+                               INTO STRICT status;
+
+                       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?
+                                       RETURN new;
+                               WHEN TOO_MANY_ROWS THEN
+                                       RAISE EXCEPTION '% is not unique in %.%',
+                                               ts_str, tbl, tscol;
+               END;
+
+               IF status = 0 THEN
+                       -- timestamps match
+                       EXECUTE 'UPDATE ' || tbl
+                               || ' SET ' || vcol || ' = ' || update_qry
+                               || ' WHERE ' || tscol || ' = ' || ts_str
+                               || ' RETURNING ' || tscol || ', ' || vcol
+                               INTO STRICT newts, new;
+               ELSIF status < 0 THEN
+                       -- someone else inserted older data in the meantime
+                       -- => try again
+                       CONTINUE;
+               ELSE
+                       RAISE EXCEPTION '% is too old in %.%', ts_str, tbl, tscol;
+               END IF;
+               EXIT;
+       END LOOP;
        RETURN new;
 END;
 $$;