On Sat, Apr 1, 2017 at 1:08 AM, Robert Haas <robertmh...@gmail.com> wrote: > On Mon, Mar 27, 2017 at 5:39 AM, Ashutosh Sharma <ashu.coe...@gmail.com> > wrote: >> Thanks for reporting this problem. Could you please let me know on for >> how long did you run sqlsmith to get this crash. However, I have found >> the reason for this crash. This is basically happening when trying to >> retrieve the tuples using cursor. Basically the current hash index >> scan work tuple-at-a-time which means once it finds tuple on page, it >> releases lock from the page but keeps pin on it and finally returns >> the tuple. When the requested number of tuples are processed there is >> no lock on the page that was being scanned but yes there is a pin on >> it. Finally, when trying to close a cursor at the end of scan, if any >> killed tuples has been identified we try to first mark these items as >> dead with the help of _hash_kill_items(). But, since we only have pin >> on this page, the assert check 'LWLockHeldByMe()' fails. > > Instead of adding bool haveLock to _hash_kill_items, how about just > having the caller acquire the lock before calling the function and > release it afterwards? Since the acquire is at the beginning of the > function and the release at the end, there seems to be no point in > putting the acquire/release inside the function rather than in the > caller.
Well, That is another option but the main idea was to be inline with the btree code. Moreover, I am not sure if acquiring lwlock inside hashendscan (basically the place where we are trying to close down the things) would look good. -- With Regards, Ashutosh Sharma EnterpriseDB:http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers