Databases
StackOverflow2013
Postsdbo
POProblems using MySql View - extremly slow, but why?
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POProblems using MySql View - extremly slow, but why?
    primarykey
    data
    text
    <p>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.</p> <p>I have the following view:</p> <pre><code>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); </code></pre> <p>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:</p> <p>//![Explain Select from View][1]</p> <p>I cannot post images without having 10 reputations, so I will try it like this:</p> <p>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.</p> <p>//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:</p> <p>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.</p> <p>Rebuilding the indexes and run the query directly in php -> More code in php, but much fatser - Now speed up to nearly 13 seconds :)</p> <p>Updating the database with new fields includes an procedure to find the currently newest status.</p> <p>So the new query is just like this:</p> <pre><code>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 </code></pre> <p>//[1]: <a href="http://i.stack.imgur.com/TPw6s.png" rel="nofollow">http://i.stack.imgur.com/TPw6s.png</a></p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USBenjamin
    1. USDaKirsche
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POProblems using MySql View - extremly slow, but why?
      1. USDaKirsche
      1. VTFavorite
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload