I have a big problem using a mysql view. I am generating a view in which I am joining several tables to receive the informations i really need.
I have the following view:
CREATE OR REPLACE VIEW view_test AS
SELECT nve_nr.nve_nvenr AS collonr,
CONCAT (adr_emp.adr_name1, "\n", adr_emp.adr_name2, "\n", adr_emp.adr_strasse, "\n", adr_emp.adr_land , " - ", adr_emp.adr_plz, " ", adr_emp.adr_ort) AS emp_adr,
UNIX_TIMESTAMP((SELECT MAX(t_1.colst_timestamp) FROM tbl_collo_status t_1 WHERE t_1.colst_nve_id =
nve_nr.nve_id AND t_1.colst_status_code IN (10, 11, 76))) AS status_x,
UNIX_TIMESTAMP((SELECT MAX(t_2.colst_timestamp) FROM tbl_collo_status t_2 WHERE t_2.colst_nve_id =
nve_nr.nve_id AND t_2.colst_status_code IN (20,25,91))) AS status_y,
UNIX_TIMESTAMP((SELECT MAX(t_3.colst_timestamp) FROM tbl_collo_status t_3 WHERE t_3.colst_nve_id =
nve_nr.nve_id AND t_3.colst_status_code IN (30,99,104))) AS status_z,
TIME_TO_SEC(TIMEDIFF((SELECT MAX(t_2.colst_timestamp) FROM tbl_collo_status t_2 WHERE t_2.colst_nve_id =
nve_nr.nve_id AND t_2.colst_status_code IN (20,25,91)), (SELECT MAX(t_1.colst_timestamp) FROM tbl_collo_status t_1
WHERE t_1.colst_nve_id = nve_nr.nve_id AND t_1.colst_status_code IN (10, 11, 76)))) AS timediff_xy,
TIME_TO_SEC(TIMEDIFF((SELECT MAX(t_3.colst_timestamp) FROM tbl_collo_status t_3 WHERE t_3.colst_nve_id =
nve_nr.nve_id AND t_3.colst_status_code IN (30,99,104)), (SELECT MAX(t_2.colst_timestamp) FROM tbl_collo_status t_2
WHERE t_2.colst_nve_id = nve_nr.nve_id AND t_2.colst_status_code IN (20,25,91)))) AS timediff_yz,
TIME_TO_SEC(TIMEDIFF((SELECT MAX(t_3.colst_timestamp) FROM tbl_collo_status t_3 WHERE t_3.colst_nve_id =
nve_nr.nve_id AND t_3.colst_status_code IN (30,99,104)), (SELECT MAX(t_1.colst_timestamp) FROM tbl_collo_status t_1
WHERE t_1.colst_nve_id = nve_nr.nve_id AND t_1.colst_status_code IN (10, 11, 76)))) AS timediff_xz,
CAST(SUBSTR(nve_nr.nve_nvenr, 1, 3) AS UNSIGNED INTEGER) AS filter_collonr,
(SELECT t_5.colst_status_code FROM tbl_collo_status t_5 WHERE t_5.colst_nve_id=nve_nr.nve_id ORDER BY
t_5.colst_timestamp DESC LIMIT 1) AS filter_last_status,
sdg.sdg_kunde AS filter_kunden_id,
sdg.sdg_id AS filter_sdg_id,
nve_nr.nve_id AS filter_nve_id,
adr_emp.adr_id AS filter_adr_emp_id
FROM ((tbl_nve_nr nve_nr LEFT JOIN tbl_sendungen sdg ON nve_nr.nve_sdg_id = sdg.sdg_id)
LEFT JOIN tbl_adressen adr_emp ON adr_emp.adr_id = sdg.sdg_adr2_id);
Now I have more than 250.000 datasets in that view an if I start a select on that View I will take more than 20 minutes to receive the result. The Explain Select will return the following:
//![Explain Select from View][1]
I cannot post images without having 10 reputations, so I will try it like this:
Can anyone tell me what I can do to speed up the view? On performing the query without using a View will take about 2 minutes with an Limit of 25 datasets that shouzld be selected from that 250.000 avaiable datasets.
//EDIT: So I've solved the problem on another way :) The solution described below does not maek the SQL-Query works faster enough, so I solved on the following way:
Dropping the views, because they are not needed any more, Altering tables nve_nr adding two fields for last status and timestamp of that. Creating a Trigger on collo_status that replaces that values, if timestamp is newer that existing. -> So one subquery less - Speeds up from 2 minutes to nearly 60 seconds.
Rebuilding the indexes and run the query directly in php -> More code in php, but much fatser - Now speed up to nearly 13 seconds :)
Updating the database with new fields includes an procedure to find the currently newest status.
So the new query is just like this:
SELECT SQL_CALC_FOUND_ROWS
sdg.sdg_lieferschein AS referenz,
nve_nr.nve_nvenr AS collonr,
nve_nr.nve_last_timestamp AS filter_status_time,
nve_nr.nve_last_status AS filter_last_status,
sdg.sdg_kunde AS filter_kunden_id,
sdg.sdg_id AS filter_sdg_id,
nve_nr.nve_id AS filter_nve_id,
adr_emp.adr_id AS filter_adr_emp_id,
adr_emp.adr_name1 AS emp_adr_name1,
adr_emp.adr_name2 AS emp_adr_name2,
adr_emp.adr_land AS emp_adr_land,
adr_emp.adr_plz AS emp_adr_plz,
adr_emp.adr_ort AS emp_adr_ort,
UNIX_TIMESTAMP(t_1.colst_timestamp) AS status_x,
t_1.colst_status_code AS status_code_x,
UNIX_TIMESTAMP(t_2.colst_timestamp) AS status_y,
t_2.colst_status_code AS status_code_y,
UNIX_TIMESTAMP(t_3.colst_timestamp) AS status_z,
t_3.colst_status_code AS status_code_z,
TIME_TO_SEC(TIMEDIFF(t_2.colst_timestamp, t_1.colst_timestamp)) AS timediff_xy,
TIME_TO_SEC(TIMEDIFF(t_3.colst_timestamp, t_2.colst_timestamp)) AS timediff_yz,
TIME_TO_SEC(TIMEDIFF(t_3.colst_timestamp, t_1.colst_timestamp)) AS timediff_xz,
CAST(SUBSTR(nve_nr.nve_nvenr, 1, 3) AS UNSIGNED INTEGER) AS filter_collonr
FROM tbl_nve_nr nve_nr
LEFT JOIN tbl_sendungen sdg
ON nve_nr.nve_sdg_id = sdg.sdg_id
LEFT JOIN tbl_adressen adr_emp
ON (adr_emp.adr_id = sdg.sdg_adr2_id)
LEFT JOIN tbl_collo_status t_1
ON (t_1.colst_nve_id = nve_nr.nve_id AND t_1.colst_aktiv = 1 AND t_1.colst_status_code IN (10, 11, 76))
LEFT JOIN tbl_collo_status t_2
ON (t_2.colst_nve_id = nve_nr.nve_id AND t_2.colst_aktiv = 1 AND t_2.colst_status_code IN (20,25,91))
LEFT JOIN tbl_collo_status t_3
ON (t_3.colst_nve_id = nve_nr.nve_id AND t_3.colst_aktiv = 1 AND t_3.colst_status_code IN (30,99,104))
GROUP BY collonr
ORDER BY collonr DESC
LIMIT 900, 75
