Problem with queries with filters on aliases.
Posted: Fri Apr 19, 2019 8:57 am
We have dp type "eRemont2" with only one 1 dp without aliases. "Select alert" from 1 dp takes 1,7 seconds if we use alias filter and don't find alias.
Then we set alias “sfasfasdfasf1231231#”, and run query again. Execute time is 0.147.
Any way these queries don't find DPE with alert_hdl. Why does it take such time? Why if we have found one DPE with alias, it takes 0,147 seconds, but if not - 1,7 seconds?
WinCC OA 3.14 patch 24
Code: Select all
SELECT ALERT '_alert_hdl.._ack_state', '_alert_hdl.._ack_time', '_alert_hdl.._add_value_7', '_alert_hdl.._add_value_8', '_alert_hdl.._class',
'_alert_hdl.._direction', '_alert_hdl.._ackable', '_alert_hdl.._value', '_alert_hdl.._text', '_alert_hdl.._system_time', '_alert_hdl.._comment',
'_alert_hdl.._value_status64'
FROM '@*1*#' WHERE _DPT = "eRemont2"
Any way these queries don't find DPE with alert_hdl. Why does it take such time? Why if we have found one DPE with alias, it takes 0,147 seconds, but if not - 1,7 seconds?
WinCC OA 3.14 patch 24