Adds CDB_TableMetadataTouch function to be able to upsert updated_at

value in cdb_tablemetadata

scripts-available/CDB_TableMetadata.sql

@@ -118,3 +118,21 @@ CREATE TRIGGER table_modified AFTER INSERT OR UPDATE
 ON CDB_TableMetadata FOR EACH ROW EXECUTE PROCEDURE
  _CDB_TableMetadata_Updated();
 
+
+-- similar to TOUCH(1) in unix filesystems but for table in cdb_tablemetadata
+CREATE OR REPLACE FUNCTION public.CDB_TableMetadataTouch(tablename regclass)
+    RETURNS void AS
+    $$
+    BEGIN
+        WITH upsert AS (
+            UPDATE public.cdb_tablemetadata
+            SET updated_at = NOW()
+            WHERE tabname = tablename
+            RETURNING *
+        )
+        INSERT INTO public.cdb_tablemetadata (tabname, updated_at)
+            SELECT tablename, NOW()
+            WHERE NOT EXISTS (SELECT * FROM upsert);
+    END;
+    $$
+LANGUAGE 'plpgsql' VOLATILE STRICT;

test/extension/run_at_cartodb_schema.sql

@@ -1,3 +1,4 @@
 SET SCHEMA 'cartodb';
 \i scripts-available/CDB_Quota.sql
+\i scripts-available/CDB_TableMetadata.sql
 SET SCHEMA 'public';

test/extension/test.sh

@@ -75,6 +75,15 @@ function sql() {
             set_failed
         fi
     fi
+
+    if [[ "$3" == "should-not" ]]
+    then
+        if [[ "${RESULT}" == "$4" ]]
+        then
+            log_error "QUERY '${QUERY}' did not expect '${RESULT}'"
+            set_failed
+        fi
+    fi
 }
 
 
@@ -277,6 +286,26 @@ function test_quota_for_each_user() {
     sql cdb_testmember_2 "SELECT cartodb.CDB_UserDataSize('cdb_testmember_2'::TEXT);" should 4096
 }
 
+function test_cdb_tablemetadatatouch() {
+    sql "CREATE TABLE touch_example (a int)"
+    sql postgres "SELECT updated_at FROM CDB_TableMetadata WHERE tabname = 'touch_example'::regclass;" should ''
+    sql "SELECT CDB_TableMetadataTouch('touch_example');"
+    sql postgres "SELECT updated_at FROM CDB_TableMetadata WHERE tabname = 'touch_example'::regclass;" should-not ''
+
+    # Another call doesn't fail
+    sql "SELECT CDB_TableMetadataTouch('touch_example');"
+    sql postgres "SELECT updated_at FROM CDB_TableMetadata WHERE tabname = 'touch_example'::regclass;" should-not ''
+
+
+
+    #### test tear down
+    sql 'DROP TABLE touch_example;'
+}
+
+function test_cdb_tablemetadatatouch_fails_for_unexistent_table() {
+    sql postgres "SELECT CDB_TableMetadataTouch('unexistent_example');" fails
+}
+
 #################################################### TESTS END HERE ####################################################
 
 run_tests $@