Hi Ranier, Thanks for looking into this!
I am not sure why but your reply does not show up in the thread, so I copied your reply and answered it in the thread for visibility. On Tue, 7 May 2024 at 16:28, Ranier Vilela <ranier...@gmail.com> wrote: > > I know it's coming from copy-and-paste, but > I believe the flags could be: > - dstfd = OpenTransientFile(tofile, O_RDWR | O_CREAT | O_EXCL | PG_BINARY); > + dstfd = OpenTransientFile(tofile, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL | > PG_BINARY); > > The flags: > O_WRONLY | O_TRUNC > > Allow the OS to make some optimizations, if you deem it possible. > > The flag O_RDWR indicates that the file can be read, which is not true in > this case. > The destination file will just be written. You may be right about the O_WRONLY flag but I am not sure about the O_TRUNC flag. O_TRUNC from the linux man page [1]: If the file already exists and is a regular file and the access mode allows writing (i.e., is O_RDWR or O_WRONLY) it will be truncated to length 0. If the file is a FIFO or terminal device file, the O_TRUNC flag is ignored. Otherwise, the effect of O_TRUNC is unspecified. But it should be already checked if the destination directory already exists in dbcommands.c file in createdb() function [2], so this should not happen. [1] https://man7.org/linux/man-pages/man2/open.2.html [2] /* * If database OID is configured, check if the OID is already in use or * data directory already exists. */ if (OidIsValid(dboid)) { char *existing_dbname = get_database_name(dboid); if (existing_dbname != NULL) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE)), errmsg("database OID %u is already in use by database \"%s\"", dboid, existing_dbname)); if (check_db_file_conflict(dboid)) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE)), errmsg("data directory with the specified OID %u already exists", dboid)); } else { /* Select an OID for the new database if is not explicitly configured. */ do { dboid = GetNewOidWithIndex(pg_database_rel, DatabaseOidIndexId, Anum_pg_database_oid); } while (check_db_file_conflict(dboid)); } -- Regards, Nazir Bilal Yavuz Microsoft
