Re: [HACKERS] pageinspect option to forgo buffer locking?

On 2017-11-09 17:14:11 -0500, Tom Lane wrote: > If we do this, I'd suggest exposing it as a separate SQL function > get_raw_page_unlocked() rather than as an option to get_raw_page(). > > The reasoning is that if we ever allow these functions to be controlled > via GRANT instead of hardwired

Re: [HACKERS] pageinspect option to forgo buffer locking?

Robert Haas writes: > On Thu, Nov 9, 2017 at 12:58 PM, Andres Freund wrote: >> You can already pass arbitrary byteas to heap_page_items(), so I don't >> see how this'd change anything exposure-wise? Or are you thinking that >> users would continually do

Re: [HACKERS] pageinspect option to forgo buffer locking?

On Thu, Nov 9, 2017 at 12:58 PM, Andres Freund wrote: > You can already pass arbitrary byteas to heap_page_items(), so I don't > see how this'd change anything exposure-wise? Or are you thinking that > users would continually do this with actual page contents and would be >

Re: [HACKERS] pageinspect option to forgo buffer locking?

On 2017-11-09 12:55:30 -0500, Robert Haas wrote: > On Thu, Nov 9, 2017 at 12:49 PM, Andres Freund wrote: > > Occasionally, when debugging issues, I find it quite useful to be able > > to do a heap_page_items() on a page that's actually locked exclusively > > concurrently. E.g.

Re: [HACKERS] pageinspect option to forgo buffer locking?

On Thu, Nov 9, 2017 at 12:49 PM, Andres Freund wrote: > Occasionally, when debugging issues, I find it quite useful to be able > to do a heap_page_items() on a page that's actually locked exclusively > concurrently. E.g. investigating the recent multixact vacuuming issues, >

Re: [HACKERS] pageinspect option to forgo buffer locking?

On Thu, Nov 9, 2017 at 9:49 AM, Andres Freund wrote: > Currently the locking in get_raw_page_internal() prevents that. If it's > an option defaulting to off, I don't see why we couldn't allow that to > skip locking the page's contents. Obviously you can get corrupted >