Opened 17 years ago
Last modified 13 years ago
#7121 closed
queryset-rf does not always honor cache — at Initial Version
Reported by: | Owned by: | nobody | |
---|---|---|---|
Component: | Uncategorized | Version: | dev |
Severity: | Keywords: | qsrf-cleanup queryset-rf, cache | |
Cc: | Triage Stage: | Design decision needed | |
Has patch: | no | Needs documentation: | no |
Needs tests: | no | Patch needs improvement: | no |
Easy pickings: | no | UI/UX: | no |
Description
Playing around in the shell and watching postgresql.log I found out the following:
Method a)
list = Article.objects.filter(idgt=130).order_by('-id')[0:2]
list[0] # Performs SQL query with LIMIT 1
list[1] # Performs another SQL query with LIMIT 1 OFFSET 2
Method b)
list = Article.objects.filter(idgt=130).order_by('-id')[0:2]
list # Performs an SQL query with LIMIT 2
list[0] # Hits the cache
list[1] # Hits the cache
Calling list[0] afterwards will invoke the SQL query with LIMIT 1
Calling list[1] after this will invoke another query with LIMT 1 OFFSET 1
b) Calling just "list" afterwards first and then calling list[0] and list[1]
will honor the cache and therefore only one SQL query gets fired.