Στις 17-09-2011, ημέρα Σαβ, και ώρα 22:55 -0700, ο/η Robert Rohde έγραψε:
On Sat, Sep 17, 2011 at 4:56 PM, Anthony wikimail@inbox.org wrote:
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For offline analyses, there's no need to change the online database tables.
Need? That's debatable, but one of the major motivators is the desire to have hash values in database dumps (both for revert checks and for checksums on correct data import / export). Both of those are "offline" uses, but it is beneficial to have that information precomputed and stored rather than frequently regenerated.
If we don't have it in the online database tables, this defeats the purpose of having the value in there at all, for the purpose of generating the XML dumps.
Recall that the dumps are generated in two passes; in the first pass we retrieve from the db and record all of the metadata about revisions, and in the second (time-comsuming) pass we re-use the text of the revisions from a previous dump file if the text is in there. We want to compare the has of that text against what the online database says the hash is; if they don't match, we want to fetch the live copy.
I refer folks to bug 23264 [1] as proof that mismatch between the metadata and the text has crept in in the past; changes to MW code in other places than the backups scripts can cause quite subtle breakage.
Ariel