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$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.8 2003/11/29 19:51:39 pgsql Exp $

$PostgreSQL: pgsql/doc/src/sgml/ref/pg_resetxlog.sgml,v 1.9 2004/12/20 01:42:09 tgl Exp $

PostgreSQL documentation

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<arg> -n </arg>

<arg> -o <replaceable class="parameter">oid</replaceable> </arg>

<arg> -x <replaceable class="parameter">xid</replaceable> </arg>

<arg> -l <replaceable class="parameter">fileid</replaceable>,<replaceable class="parameter">seg</replaceable> </arg>

<arg> -l <replaceable class="parameter">timelineid</replaceable>,<replaceable class="parameter">fileid</replaceable>,<replaceable class="parameter">seg</replaceable> </arg>

<arg choice="plain"><replaceable>datadir</replaceable></arg>

</cmdsynopsis>

</refsynopsisdiv>

<command>pg_resetxlog</command> is unable to determine appropriate values

by reading <filename>pg_control</>. A safe value for the

next transaction ID may be determined by looking for the numerically largest

file name in the directory <filename>pg_clog</> under the data directory, adding one,

file name in the directory <filename>pg_clog</> under the data directory,

adding one,

and then multiplying by 1048576. Note that the file names are in

hexadecimal. It is usually easiest to specify the switch value in

hexadecimal too. For example, if <filename>0011</> is the largest entry

in <filename>pg_clog</>, <literal>-x 0x1200000</> will work (five trailing

zeroes provide the proper multiplier).

The WAL starting address should be

larger than any file number currently existing in

the directory <filename>pg_xlog</> under the data directory. The addresses are also in hexadecimal and

have two parts. For example, if <filename>000000FF0000003A</> is the

largest entry in <filename>pg_xlog</>, <literal>-l 0xFF,0x3B</> will work.

larger than any file name currently existing in

the directory <filename>pg_xlog</> under the data directory.

These names are also in hexadecimal and have three parts. The first

part is the <quote>timeline ID</> and should usually be kept the same.

Do not choose a value larger than 255 (<literal>0xFF</>) for the third

part; instead increment the second part and reset the third part to 0.

For example, if <filename>00000001000000320000004A</> is the

largest entry in <filename>pg_xlog</>, <literal>-l 0x1,0x32,0x4B</> will

work; but if the largest entry is

<filename>000000010000003A000000FF</>, choose <literal>-l 0x1,0x3B,0x0</>

or more.

There is no comparably easy way to determine a next OID that's beyond

the largest one in the database, but fortunately it is not critical to

get the next-OID setting right.

boolnoupdate= false;

TransactionIdset_xid=0;

Oidset_oid=0;

uint32minXlogId=0,

uint32minXlogTli=0,

minXlogId=0,

minXlogSeg=0;

char*endptr;

char*endptr2;

char*endptr3;

char*DataDir;

intfd;

charpath[MAXPGPATH];

break;

case'l':

minXlogId=strtoul(optarg,&endptr,0);

minXlogTli=strtoul(optarg,&endptr,0);

if (endptr==optarg||*endptr!=',')

{

fprintf(stderr,_("%s: invalid argument for option -l\n"),progname);

fprintf(stderr,_("Try \"%s --help\" for more information.\n"),progname);

exit(1);

}

minXlogSeg=strtoul(endptr+1,&endptr2,0);

if (endptr2==endptr+1||*endptr2!='\0')

minXlogId=strtoul(endptr+1,&endptr2,0);

if (endptr2==endptr+1||*endptr2!=',')

{

fprintf(stderr,_("%s: invalid argument for option -l\n"),progname);

fprintf(stderr,_("Try \"%s --help\" for more information.\n"),progname);

exit(1);

}

minXlogSeg=strtoul(endptr2+1,&endptr3,0);

if (endptr3==endptr2+1||*endptr3!='\0')

{

fprintf(stderr,_("%s: invalid argument for option -l\n"),progname);

fprintf(stderr,_("Try \"%s --help\" for more information.\n"),progname);

if (set_oid!=0)

ControlFile.checkPointCopy.nextOid=set_oid;

if (minXlogTli>ControlFile.checkPointCopy.ThisTimeLineID)

ControlFile.checkPointCopy.ThisTimeLineID=minXlogTli;

if (minXlogId>ControlFile.logId||

(minXlogId==ControlFile.logId&&

minXlogSeg>ControlFile.logSeg))

errno=0;

while ((xlde=readdir(xldir))!=NULL)

{

if (strlen(xlde->d_name)==16&&

strspn(xlde->d_name,"0123456789ABCDEF")==16)

if (strlen(xlde->d_name)==24&&

strspn(xlde->d_name,"0123456789ABCDEF")==24)

{

snprintf(path,MAXPGPATH,"%s/%s",XLogDir,xlde->d_name);

if (unlink(path)<0)

printf(_("Usage:\n %s [OPTION]... DATADIR\n\n"),progname);

printf(_("Options:\n"));

printf(_(" -f force update to be done\n"));

printf(_(" -lFILEID,SEG force minimum WAL starting location for new transaction log\n"));

printf(_(" -lTLI,FILE,SEG force minimum WAL starting location for new transaction log\n"));

printf(_(" -n no update, just show extracted control values (for testing)\n"));

printf(_(" -o OID set next OID\n"));

printf(_(" -x XID set next transaction ID\n"));