On 2016-04-23 1:20 AM, Michele Pradella wrote: > I have an In-Memory DB that is written and read from connections of the > same process. All good with shared cache, but I found that TableLock > occur more often on In-Memory than on disk DB, probably because in > memory we can't use WAL. > > Anyway I found the PRAGMA read_uncommitted that from documentation seams > a way to read without the problem of table lock. The question is about > this sentence "This can lead to inconsistent query results if another > database connection modifies a table while it is being read". > "inconsistent" means just "out of date"? or there can be some other type > of inconsistent data?
Usually "inconsistent" means you see a result that is partially an old value and partially a new one, such as if you open a photograph and find that the top half was overwritten with a different photo; you get the incomplete results of a change in progress, for example, say if one is recording a bank funds transfer with one record showing an account debit and another showing an account credit, readers may only see one of those and then they see a database where the numbers don't add up properly, as if it were corrupt; that is what "inconsistent" means. -- Darren Duncan
