Re: [HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
I wrote: > "Kurt Harriman" <[EMAIL PROTECTED]> writes: >> Just noticed buffile.c:292 doesn't look quite right where >> BufFileDumpBuffer calls FileWrite: >> bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); >> It looks as though it would write the same data each time the >> loop is iterated. Would this be better? >> bytestowrite = FileWrite(thisfile, file->buffer + wpos, bytestowrite); > Yeah, I think you're right. FYI, I was able to exercise the bug by changing RELSEG_SIZE to 2 within buffile.c and then running this script in the regression database: set work_mem = '64kB'; begin; declare c scroll cursor for select * from tenk1 a join tenk1 b using(two); fetch 1 from c; fetch 100 from c; fetch backward 10 from c; fetch 100 from c; fetch backward 10 from c; fetch 100 from c; fetch backward 100 from c; commit; It doesn't crash with the fix applied. Thanks for spotting it. regards, tom lane ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
Alvaro Herrera wrote: > Bruce Momjian wrote: > > > > This has been saved for the 8.4 release: > > > > http://momjian.postgresql.org/cgi-bin/pgpatches_hold > > Huh, no, this is a bug and should be fixed right away. OK, moved to the 8.3 patch queue. --- > > > --- > > > > Tom Lane wrote: > > > "Kurt Harriman" <[EMAIL PROTECTED]> writes: > > > > Just noticed buffile.c:292 doesn't look quite right where > > > > BufFileDumpBuffer calls FileWrite: > > > > bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); > > > > It looks as though it would write the same data each time the > > > > loop is iterated. Would this be better? > > > > bytestowrite = FileWrite(thisfile, file->buffer + wpos, > > > > bytestowrite); > > > > > > Yeah, I think you're right. We've probably not seen this because in > > > most usages the buffer is always block-aligned, but it looks possible > > > for tuplestore.c to get out of alignment if its concurrent write/read > > > feature is exercised just so. Do you want to try demonstrating the bug > > > with a smaller-than-normal setting of MAX_PHYSICAL_FILESIZE? > > > -- > Alvaro Herrerahttp://www.CommandPrompt.com/ > The PostgreSQL Company - Command Prompt, Inc. -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
Bruce Momjian wrote: > > This has been saved for the 8.4 release: > > http://momjian.postgresql.org/cgi-bin/pgpatches_hold Huh, no, this is a bug and should be fixed right away. > --- > > Tom Lane wrote: > > "Kurt Harriman" <[EMAIL PROTECTED]> writes: > > > Just noticed buffile.c:292 doesn't look quite right where > > > BufFileDumpBuffer calls FileWrite: > > > bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); > > > It looks as though it would write the same data each time the > > > loop is iterated. Would this be better? > > > bytestowrite = FileWrite(thisfile, file->buffer + wpos, > > > bytestowrite); > > > > Yeah, I think you're right. We've probably not seen this because in > > most usages the buffer is always block-aligned, but it looks possible > > for tuplestore.c to get out of alignment if its concurrent write/read > > feature is exercised just so. Do you want to try demonstrating the bug > > with a smaller-than-normal setting of MAX_PHYSICAL_FILESIZE? -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
This has been saved for the 8.4 release: http://momjian.postgresql.org/cgi-bin/pgpatches_hold --- Tom Lane wrote: > "Kurt Harriman" <[EMAIL PROTECTED]> writes: > > Just noticed buffile.c:292 doesn't look quite right where > > BufFileDumpBuffer calls FileWrite: > > bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); > > It looks as though it would write the same data each time the > > loop is iterated. Would this be better? > > bytestowrite = FileWrite(thisfile, file->buffer + wpos, bytestowrite); > > Yeah, I think you're right. We've probably not seen this because in > most usages the buffer is always block-aligned, but it looks possible > for tuplestore.c to get out of alignment if its concurrent write/read > feature is exercised just so. Do you want to try demonstrating the bug > with a smaller-than-normal setting of MAX_PHYSICAL_FILESIZE? > > regards, tom lane > > ---(end of broadcast)--- > TIP 5: don't forget to increase your free space map settings -- Bruce Momjian <[EMAIL PROTECTED]> http://momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---(end of broadcast)--- TIP 6: explain analyze is your friend
Re: [HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
"Kurt Harriman" <[EMAIL PROTECTED]> writes: > Just noticed buffile.c:292 doesn't look quite right where > BufFileDumpBuffer calls FileWrite: > bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); > It looks as though it would write the same data each time the > loop is iterated. Would this be better? > bytestowrite = FileWrite(thisfile, file->buffer + wpos, bytestowrite); Yeah, I think you're right. We've probably not seen this because in most usages the buffer is always block-aligned, but it looks possible for tuplestore.c to get out of alignment if its concurrent write/read feature is exercised just so. Do you want to try demonstrating the bug with a smaller-than-normal setting of MAX_PHYSICAL_FILESIZE? regards, tom lane ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings
[HACKERS] BufFileWrite across MAX_PHYSICAL_FILESIZE boundary
Just noticed buffile.c:292 doesn't look quite right where BufFileDumpBuffer calls FileWrite: bytestowrite = FileWrite(thisfile, file->buffer, bytestowrite); It looks as though it would write the same data each time the loop is iterated. Would this be better? bytestowrite = FileWrite(thisfile, file->buffer + wpos, bytestowrite); ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
