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Add option to include WAL in base backup

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When included, this makes the base backup a complete working
"clone" of the initial database, ready to have a postmaster
started against it without the need to set up any log archiving
or similar.

Magnus Hagander, reviewed by Fujii Masao and Heikki Linnakangas
This commit is contained in:
Magnus Hagander
2011-01-30 21:30:09 +01:00
parent 5d5678d7c3
commit 507069de6d
8 changed files with 197 additions and 44 deletions
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149
src/backend/replication/basebackup.c
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@ -37,6 +37,7 @@ typedef struct
const char *label;
bool progress;
bool fastcheckpoint;
bool includewal;
} basebackup_options;
@ -46,11 +47,17 @@ static void _tarWriteHeader(char *filename, char *linktarget,
struct stat * statbuf);
static void send_int8_string(StringInfoData *buf, int64 intval);
static void SendBackupHeader(List *tablespaces);
static void SendBackupDirectory(char *location, char *spcoid);
static void base_backup_cleanup(int code, Datum arg);
static void perform_base_backup(basebackup_options *opt, DIR *tblspcdir);
static void parse_basebackup_options(List *options, basebackup_options *opt);
/*
* Size of each block sent into the tar stream for larger files.
*
* XLogSegSize *MUST* be evenly dividable by this
*/
#define TAR_SEND_SIZE 32768
typedef struct
{
char *oid;
@ -78,7 +85,10 @@ base_backup_cleanup(int code, Datum arg)
static void
perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
{
do_pg_start_backup(opt->label, opt->fastcheckpoint);
XLogRecPtr startptr;
XLogRecPtr endptr;
startptr = do_pg_start_backup(opt->label, opt->fastcheckpoint);
PG_ENSURE_ERROR_CLEANUP(base_backup_cleanup, (Datum) 0);
{
@ -87,12 +97,6 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
struct dirent *de;
tablespaceinfo *ti;
/* Add a node for the base directory */
ti = palloc0(sizeof(tablespaceinfo));
ti->size = opt->progress ? sendDir(".", 1, true) : -1;
tablespaces = lappend(tablespaces, ti);
/* Collect information about all tablespaces */
while ((de = ReadDir(tblspcdir, "pg_tblspc")) != NULL)
{
@ -120,6 +124,10 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
tablespaces = lappend(tablespaces, ti);
}
/* Add a node for the base directory at the end */
ti = palloc0(sizeof(tablespaceinfo));
ti->size = opt->progress ? sendDir(".", 1, true) : -1;
tablespaces = lappend(tablespaces, ti);
/* Send tablespace header */
SendBackupHeader(tablespaces);
@ -128,13 +136,102 @@ perform_base_backup(basebackup_options *opt, DIR *tblspcdir)
foreach(lc, tablespaces)
{
tablespaceinfo *ti = (tablespaceinfo *) lfirst(lc);
StringInfoData buf;
SendBackupDirectory(ti->path, ti->oid);
/* Send CopyOutResponse message */
pq_beginmessage(&buf, 'H');
pq_sendbyte(&buf, 0); /* overall format */
pq_sendint(&buf, 0, 2); /* natts */
pq_endmessage(&buf);
sendDir(ti->path == NULL ? "." : ti->path,
ti->path == NULL ? 1 : strlen(ti->path),
false);
/*
* If we're including WAL, and this is the main data directory we
* don't terminate the tar stream here. Instead, we will append
* the xlog files below and terminate it then. This is safe since
* the main data directory is always sent *last*.
*/
if (opt->includewal && ti->path == NULL)
{
Assert(lnext(lc) == NULL);
}
else
pq_putemptymessage('c'); /* CopyDone */
}
}
PG_END_ENSURE_ERROR_CLEANUP(base_backup_cleanup, (Datum) 0);
do_pg_stop_backup();
endptr = do_pg_stop_backup();
if (opt->includewal)
{
/*
* We've left the last tar file "open", so we can now append the
* required WAL files to it.
*/
uint32 logid,
logseg;
uint32 endlogid,
endlogseg;
struct stat statbuf;
MemSet(&statbuf, 0, sizeof(statbuf));
statbuf.st_mode = S_IRUSR | S_IWUSR;
#ifndef WIN32
statbuf.st_uid = geteuid();
statbuf.st_gid = getegid();
#endif
statbuf.st_size = XLogSegSize;
statbuf.st_mtime = time(NULL);
XLByteToSeg(startptr, logid, logseg);
XLByteToPrevSeg(endptr, endlogid, endlogseg);
while (true)
{
/* Send another xlog segment */
char fn[MAXPGPATH];
int i;
XLogFilePath(fn, ThisTimeLineID, logid, logseg);
_tarWriteHeader(fn, NULL, &statbuf);
/* Send the actual WAL file contents, block-by-block */
for (i = 0; i < XLogSegSize / TAR_SEND_SIZE; i++)
{
char buf[TAR_SEND_SIZE];
XLogRecPtr ptr;
ptr.xlogid = logid;
ptr.xrecoff = logseg * XLogSegSize + TAR_SEND_SIZE * i;
XLogRead(buf, ptr, TAR_SEND_SIZE);
if (pq_putmessage('d', buf, TAR_SEND_SIZE))
ereport(ERROR,
(errmsg("base backup could not send data, aborting backup")));
}
/*
* Files are always fixed size, and always end on a 512 byte
* boundary, so padding is never necessary.
*/
/* Advance to the next WAL file */
NextLogSeg(logid, logseg);
/* Have we reached our stop position yet? */
if (logid > endlogid ||
(logid == endlogid && logseg > endlogseg))
break;
}
/* Send CopyDone message for the last tar file */
pq_putemptymessage('c');
}
}
/*
@ -147,6 +244,7 @@ parse_basebackup_options(List *options, basebackup_options *opt)
bool o_label = false;
bool o_progress = false;
bool o_fast = false;
bool o_wal = false;
MemSet(opt, 0, sizeof(*opt));
foreach(lopt, options)
@ -180,6 +278,15 @@ parse_basebackup_options(List *options, basebackup_options *opt)
opt->fastcheckpoint = true;
o_fast = true;
}
else if (strcmp(defel->defname, "wal") == 0)
{
if (o_wal)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("duplicate option \"%s\"", defel->defname)));
opt->includewal = true;
o_wal = true;
}
else
elog(ERROR, "option \"%s\" not recognized",
defel->defname);
@ -316,26 +423,6 @@ SendBackupHeader(List *tablespaces)
pq_puttextmessage('C', "SELECT");
}
static void
SendBackupDirectory(char *location, char *spcoid)
{
StringInfoData buf;
/* Send CopyOutResponse message */
pq_beginmessage(&buf, 'H');
pq_sendbyte(&buf, 0); /* overall format */
pq_sendint(&buf, 0, 2); /* natts */
pq_endmessage(&buf);
/* tar up the data directory if NULL, otherwise the tablespace */
sendDir(location == NULL ? "." : location,
location == NULL ? 1 : strlen(location),
false);
/* Send CopyDone message */
pq_putemptymessage('c');
}
static int64
sendDir(char *path, int basepathlen, bool sizeonly)
@ -506,7 +593,7 @@ static void
sendFile(char *filename, int basepathlen, struct stat * statbuf)
{
FILE *fp;
char buf[32768];
char buf[TAR_SEND_SIZE];
size_t cnt;
pgoff_t len = 0;
size_t pad;