[HACKERS] Re: mmap for zeroing WAL log

2001-02-28 Thread Matthew Kirkwood
On Tue, 27 Feb 2001, Tom Lane wrote: > Matthew Kirkwood <[EMAIL PROTECTED]> writes: > > I had assumed that the overhead would come from synchronous > > metadata incurring writes of at least the inode, block bitmap > > and probably an indirect block for each syscall. > > No Unix that I've ever hea

[HACKERS] Re: mmap for zeroing WAL log

2001-02-27 Thread Matthew Kirkwood
On Sat, 24 Feb 2001, Tom Lane wrote: > >> I am confused why mmap() is better than writing to a real file. > > > It isn't, except that it allows to initialise the logfile in > > one syscall, without first allocating and zeroing (and hence > > dirtying) 16Mb of memory. > > Uh, the existing code d

[HACKERS] Re: mmap for zeroing WAL log

2001-02-27 Thread Tom Lane
Matthew Kirkwood <[EMAIL PROTECTED]> writes: > I had assumed that the overhead would come from synchronous > metadata incurring writes of at least the inode, block bitmap > and probably an indirect block for each syscall. No Unix that I've ever heard of forces metadata to disk after each "write"