Analysis of main function in pg_basebackup Source Code of PostgreSQL backup tool

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I. data structure

Option

Data structure for storing options when using the tool

# ifndef HAVE_STRUCT_OPTION// tool software option struct option {const char * name;// name whether int has_arg;// contains parameters, no_argument/required_argument/optional_argument int * flag;// tag int val;// parameter value} # define no_argument 0#define required_argument 1#define optional_argument 2 * On OpenBSD and some versions of Solaris, opterr and friends are defined in * core libc rather than in a separate getopt module. Define these variables * only if configure found they aren't there by default; otherwise, this * module and its callers will just use libc's variables. (We assume that * testing opterr is sufficient for all of these.) * / # ifndef HAVE_INT_OPTERRint opterr = 1, / * if error message should be printed * / optind = 1, / * index into parent argv vector * / optopt; / * character checked for validity * / char * optarg / * argument associated with option * / # endif#define BADCH (int)'?'# define BADARG (int)':'# define EMSG "II. Source code interpretation

Pg_basebackup main function, source code is relatively simple, access to options, check, call BaseBackup () function for backup.

Intmain (int argc, char * * argv) {static struct option long_options [] = {{"help", no_argument, NULL,'?'}, {"version", no_argument, NULL,'V'}, {"pgdata", required_argument, NULL,'D'}, {"format", required_argument, NULL,'F'}, {"checkpoint", required_argument, NULL,'c'} {"create-slot", no_argument, NULL,'C'}, {"max-rate", required_argument, NULL,'r'}, {"write-recovery-conf", no_argument, NULL,'R'}, {"slot", required_argument, NULL,'S'}, {"tablespace-mapping", required_argument, NULL,'T'}, {"wal-method", required_argument, NULL 'X'}, {"gzip", no_argument, NULL,' z'}, {"compress", required_argument, NULL,'Z'}, {"label", required_argument, NULL,'l'}, {"no-clean", no_argument, NULL,'n'}, {"no-sync", no_argument, NULL,'N'}, {"dbname", required_argument, NULL 'd'}, {"host", required_argument, NULL,'h'}, {"port", required_argument, NULL,'p'}, {"username", required_argument, NULL,'U'}, {"no-password", no_argument, NULL,'w'}, {"password", no_argument, NULL,'W'}, {"status-interval", required_argument, NULL 's'}, {"verbose", no_argument, NULL,'v'}, {"progress", no_argument, NULL,'P'}, {"waldir", required_argument, NULL, 1}, {"no-slot", no_argument, NULL, 2}, {"no-verify-checksums", no_argument, NULL, 3}, {NULL, 0, NULL, 0}} / / (full) option / / option's ASCII value int c; / / option index number int option_index; / / Program name progname = get_progname (argv [0]); set_pglocale_pgservice (argv [0], PG_TEXTDOMAIN ("pg_basebackup")) If (argc > 1) {/ / display help information if (strcmp (argv [1], "--help") = = 0 | | strcmp (argv [1], "-?") = = 0) {usage (); exit (0) } else if (strcmp (argv [1], "- V") = = 0 | | strcmp (argv [1], "--version") = = 0) {/ / display version information puts ("pg_basebackup (PostgreSQL)" PG_VERSION); exit (0);}} atexit (cleanup_directories_atexit) / / getopt_long-- > get the option while (c = getopt_long (argc, argv, "CD:F:r:RS:T:X:l:nNzZ:d:c:h:p:U:s:wWkvP", long_options) & option_index)! =-1) {switch (c) / / set the parameter {case'Craft: create_slot = true according to the option Break; case'Downs: basedir = pg_strdup (optarg); break; case'Fables: if (strcmp (optarg, "p") = = 0 | | strcmp (optarg, "plain") = = 0) format ='p' / / do not compress else if (strcmp (optarg, "t") = = 0 | | strcmp (optarg, "tar") = = 0) format ='t' / / tar package else {fprintf (stderr, _ ("% s: invalid output format\"% s\ ", must be\" plain\ "or\" tar\ "\ n"), progname, optarg); exit (1) } break; case'ringing: maxrate = parse_max_rate (optarg); break; case'ringing: writerecoveryconf = true; break Case'scars: / * * When specifying replication slot name, use a permanent * slot. * specify the name of the replication slot, then use the persistence slot * / replication_slot = pg_strdup (optarg); temp_replication_slot = false; break; case 2: no_slot = true; break Case'Tables: tablespace_list_append (optarg); break; case'Xboxes: if (strcmp (optarg, "n") = = 0 | | strcmp (optarg, "none") = = 0) {includewal = NO_WAL } else if (strcmp (optarg, "f") = = 0 | | strcmp (optarg, "fetch") = = 0) {includewal = FETCH_WAL } else if (strcmp (optarg, "s") = = 0 | | strcmp (optarg, "stream") = = 0) {includewal = STREAM_WAL } else {fprintf (stderr, _ ("% s: invalid wal-method option\"% s\ ", must be\" fetch\ ",\" stream\ ", or\" none\ "\ n), progname, optarg) Exit (1);} break; case 1: xlog_dir = pg_strdup (optarg); break; case'lame: label = pg_strdup (optarg); break Case'nails: noclean = true; break; case'Names: do_sync = false; break; case 'z':#ifdef HAVE_LIBZ compresslevel = Zhuan DEFAULTING COMPRESSION investors else compresslevel = 1; / * will be rejected below * / # endif break Case'Zhuan: compresslevel = atoi (optarg); if (compresslevel)