इतनी कम संख्या में अपडेट के लिए ORDER-BY और LIMIT का उपयोग न करने का प्रयास करें।
UPDATE companies t1
join
(
SELECT c.id,@RowNum:[email protected]+1 AS RowID
FROM companies c, (SELECT @RowNum := 0)r
WHERE c.crawling = 0 AND c.url_host IS NOT NULL
ORDER BY c.last_crawled ASC
)t2
ON t2.RowID=1 AND t1.id=t2.id
SET t1.crawling = 1
संपादित करें:1
सुनिश्चित करें कि आपके पास अनुक्रमणिका (last_crawled ASC , id ASC) पर है
UPDATE companies t1
join
(
Select ID,RowID
From
(
SELECT c.id,@RowNum:[email protected]+1 AS RowID
FROM companies c, (SELECT @RowNum := 0)r
WHERE c.crawling = 0 AND c.url_host IS NOT NULL
ORDER BY c.last_crawled ASC
)t2
WHERE ROWID=1
)t3
ON t1.id=t3.id
SET t1.crawling = 1