On Thu, Oct 28, 2010 at 11:29 AM, Mark Phippard <[email protected]> wrote: > On Thu, Oct 28, 2010 at 12:23 PM, Hyrum K. Wright > <[email protected]> wrote: >> On Thu, Oct 28, 2010 at 10:09 AM, Julian Foad <[email protected]> >> wrote: >>> Bert and Erik and Philip and I discussed on IRC today the merits, or >>> lack of merits, of allowing repos-id/repos-relpath to be elided in the >>> NODES table BASE layer (op_depth = 0). >>> >>> * The data is not currently elided. >>> >>> * Some queries for locks currently assume the data is not elided. >>> >>> * Elision could save a bit of DB size, which *might* contribute to a >>> little bit of general DB performance. >>> >>> * The option of elision results in the need for all users of this data >>> to call svn_wc__db_scan_base_repos() or the internal version >>> scan_upwards_for_repos(), which is an extra maintenance burden and extra >>> run-time cost. >>> >>> We concluded it would be better to require the columns to be always >>> filled in. I'll do this soon if no objections. >> >> As I understand it, our original intention for elision was to make >> switch and relocate go much faster, since only one row would be >> updated instead of the entire tree. If that creates too much of a >> burden elsewhere, then yes, we can probably nuke it (and we can >> probably write a good enough query to make the relatively uncommon >> operations of switch and relocate only negligibly slower). >> >> This is one use case, however, and isn't necessarily the only one. > > At the same time, with code written to properly leverage SQL this is > the sort of scenario that we should not worry about anymore. SQLite > ought to be able to update all the rows in the DB faster than our old > code could walk the tree and open all the entries files, let alone > rewrite them.
Correct. And we still have to do the update crawl on a switch or relocate, no? -Hyrum
