Re: [HACKERS] SQL compatibility reminder: MySQL vs PostgreSQL
От | Josh Berkus |
---|---|
Тема | Re: [HACKERS] SQL compatibility reminder: MySQL vs PostgreSQL |
Дата | |
Msg-id | 4B943139.40503@agliodbs.com обсуждение исходный текст |
Ответы |
Re: [HACKERS] SQL compatibility reminder: MySQL vs PostgreSQL
Re: [HACKERS] SQL compatibility reminder: MySQL vs PostgreSQL |
Список | pgsql-advocacy |
Joshua, I've moved this discussion to pgsql-advocacy where it belongs. > Aside from Drupal core, its too soon to know if there will be problems > with D7 contrib but there are a few major bugs about other D6 contrib > modules. The biggest one, which I think need movement to get fixed is in > the Views module. The Views module has a bit of a hard time trying to > please both databases and its surrounding the use of DISTINCT and > restricting duplicate results. They've opted for a solution that really > hits hard on PostgreSQL's performance. Bascially, when a DISTINCT clause > is used, all other fields being selected get a custom functional called > FIRST rapped around them: SELECT DISTINCT(nid), FIRST(title), > FIRST(body), ..... The function merely returns the first value when two > values are present for that row. This is the alternate instead of > grouping by each field. Its stupid and needs to be fixed. The issue is > here: http://drupal.org/node/460838 What's the obstacle to fixing it? It seems like just changing to SELECT DISTINCT ON ... would do the trick, and would allow cutting code. --Josh Berkus
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