PostgreSQL 9.3 Have pg_basebackup --write-recovery-conf output a minimal recovery.conf

Have pg_basebackup --write-recovery-conf output a minimal recovery.conf (Zoltán B?sz?rményi, Magnus Hagander)
This simplifies setting up a standby server.

个人感觉没有太大的意义.

[测试]

-- 命令行帮助

pg93@db-172-16-3-33-> pg_basebackup --help
pg_basebackup takes a base backup of a running PostgreSQL server.

Usage:
  pg_basebackup [OPTION]...

Options controlling the output:
  -D, --pgdata=DIRECTORY receive base backup into directory
  -F, --format=p|t       output format (plain (default), tar)
  -R, --write-recovery-conf
                         write recovery.conf after backup
  -x, --xlog             include required WAL files in backup (fetch mode)
  -X, --xlog-method=fetch|stream
                         include required WAL files with specified method
  -z, --gzip             compress tar output
  -Z, --compress=0-9     compress tar output with given compression level

General options:
  -c, --checkpoint=fast|spread
                         set fast or spread checkpointing
  -l, --label=LABEL      set backup label
  -P, --progress         show progress information
  -v, --verbose          output verbose messages
  -V, --version          output version information, then exit
  -?, --help             show this help, then exit

Connection options:
  -d, --dbname=CONNSTR   connection string
  -h, --host=HOSTNAME    database server host or socket directory
  -p, --port=PORT        database server port number
  -s, --status-interval=INTERVAL
                         time between status packets sent to server (in seconds)
  -U, --username=NAME    connect as specified database user
  -w, --no-password      never prompt for password
  -W, --password         force password prompt (should happen automatically)

-- 使用pg_basebackup并使用-R选项

pg93@db-172-16-3-33-> pg_basebackup -D /pgdata/digoal/1921/data03/test -F p --write-recovery-conf
WARNING:  skipping special file "./.s.PGSQL.1999"
NOTICE:  pg_stop_backup complete, all required WAL segments have been archived
pg93@db-172-16-3-33-> cd /pgdata/digoal/1921/data03/test/

-- 自动生成的recovery.conf文件.

pg93@db-172-16-3-33-> cat recovery.conf
standby_mode = 'on'
primary_conninfo = 'user=''postgres'' port=''1999'' sslmode=''prefer'' sslcompression=''1'' '

[参考]
1. src/bin/pg_basebackup/pg_basebackup.c

00071 /* Contents of recovery.conf to be generated */
00072 static PQExpBuffer recoveryconfcontents = NULL;
...
00680             if (basetablespace && writerecoveryconf)
00681             {
00682                 char        header[512];
00683                 int         padding;
00684
00685                 tarCreateHeader(header, "recovery.conf", NULL,
00686                                 recoveryconfcontents->len,
00687                                 0600, 04000, 02000,
00688                                 time(NULL));
00689
00690                 padding = ((recoveryconfcontents->len + 511) & ~511) - recoveryconfcontents->len;
00691
00692                 WRITE_TAR_DATA(header, sizeof(header));
00693                 WRITE_TAR_DATA(recoveryconfcontents->data, recoveryconfcontents->len);
00694                 if (padding)
00695                     WRITE_TAR_DATA(zerobuf, padding);
00696             }
...
01190 /*
01191  * Write a recovery.conf file into the directory specified in basedir,
01192  * with the contents already collected in memory.
01193  */
01194 static void
01195 WriteRecoveryConf(void)
01196 {
01197     char        filename[MAXPGPATH];
01198     FILE       *cf;
01199
01200     sprintf(filename, "%s/recovery.conf", basedir);
01201
01202     cf = fopen(filename, "w");
01203     if (cf == NULL)
01204     {
01205         fprintf(stderr, _("%s: could not create file \"%s\": %s\n"), progname, filename, strerror(errno));
01206         disconnect_and_exit(1);
01207     }
01208
01209     if (fwrite(recoveryconfcontents->data, recoveryconfcontents->len, 1, cf) != 1)
01210     {
01211         fprintf(stderr,
01212                 _("%s: could not write to file \"%s\": %s\n"),
01213                 progname, filename, strerror(errno));
01214         disconnect_and_exit(1);
01215     }
01216
01217     fclose(cf);
01218 }