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Make pg_receivexlog and pg_basebackup -X stream work across timeline switches.

Browse Source 
This mirrors the changes done earlier to the server in standby mode. When
receivelog reaches the end of a timeline, as reported by the server, it
fetches the timeline history file of the next timeline, and restarts
streaming from the new timeline by issuing a new START_STREAMING command.

When pg_receivexlog crosses a timeline, it leaves the .partial suffix on the
last segment on the old timeline. This helps you to tell apart a partial
segment left in the directory because of a timeline switch, and a completed
segment. If you just follow a single server, it won't make a difference, but
it can be significant in more complicated scenarios where new WAL is still
generated on the old timeline.

This includes two small changes to the streaming replication protocol:
First, when you reach the end of timeline while streaming, the server now
sends the TLI of the next timeline in the server's history to the client.
pg_receivexlog uses that as the next timeline, so that it doesn't need to
parse the timeline history file like a standby server does. Second, when
BASE_BACKUP command sends the begin and end WAL positions, it now also sends
the timeline IDs corresponding the positions.
This commit is contained in:
Heikki Linnakangas
2013-01-17 20:23:00 +02:00
parent 8ae35e9180
commit 0b6329130e
12 changed files with 699 additions and 312 deletions
Download Patch File Download Diff File Expand all files Collapse all files

731
src/bin/pg_basebackup/receivelog.c
View File

@ -28,19 +28,24 @@
#include "streamutil.h"
/* fd for currently open WAL file */
/* fd and filename for currently open WAL file */
static int walfile = -1;
static char current_walfile_name[MAXPGPATH] = "";
static bool HandleCopyStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
char *basedir, stream_stop_callback stream_stop,
int standby_message_timeout, char *partial_suffix,
XLogRecPtr *stoppos);
/*
* Open a new WAL file in the specified directory. Store the name
* (not including the full directory) in namebuf. Assumes there is
* enough room in this buffer...
* Open a new WAL file in the specified directory.
*
* The file will be padded to 16Mb with zeroes.
* The file will be padded to 16Mb with zeroes. The base filename (without
* partial_suffix) is stored in current_walfile_name.
*/
static int
static bool
open_walfile(XLogRecPtr startpoint, uint32 timeline, char *basedir,
char *namebuf)
char *partial_suffix)
{
int f;
char fn[MAXPGPATH];
@ -50,16 +55,17 @@ open_walfile(XLogRecPtr startpoint, uint32 timeline, char *basedir,
XLogSegNo segno;
XLByteToSeg(startpoint, segno);
XLogFileName(namebuf, timeline, segno);
XLogFileName(current_walfile_name, timeline, segno);
snprintf(fn, sizeof(fn), "%s/%s.partial", basedir, namebuf);
snprintf(fn, sizeof(fn), "%s/%s%s", basedir, current_walfile_name,
partial_suffix ? partial_suffix : "");
f = open(fn, O_WRONLY | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR);
if (f == -1)
{
fprintf(stderr,
_("%s: could not open transaction log file \"%s\": %s\n"),
progname, fn, strerror(errno));
return -1;
return false;
}
/*
@ -72,17 +78,21 @@ open_walfile(XLogRecPtr startpoint, uint32 timeline, char *basedir,
_("%s: could not stat transaction log file \"%s\": %s\n"),
progname, fn, strerror(errno));
close(f);
return -1;
return false;
}
if (statbuf.st_size == XLogSegSize)
return f; /* File is open and ready to use */
{
/* File is open and ready to use */
walfile = f;
return true;
}
if (statbuf.st_size != 0)
{
fprintf(stderr,
_("%s: transaction log file \"%s\" has %d bytes, should be 0 or %d\n"),
progname, fn, (int) statbuf.st_size, XLogSegSize);
close(f);
return -1;
return false;
}
/* New, empty, file. So pad it to 16Mb with zeroes */
@ -97,7 +107,7 @@ open_walfile(XLogRecPtr startpoint, uint32 timeline, char *basedir,
free(zerobuf);
close(f);
unlink(fn);
return -1;
return false;
}
}
free(zerobuf);
@ -108,42 +118,45 @@ open_walfile(XLogRecPtr startpoint, uint32 timeline, char *basedir,
_("%s: could not seek to beginning of transaction log file \"%s\": %s\n"),
progname, fn, strerror(errno));
close(f);
return -1;
return false;
}
return f;
walfile = f;
return true;
}
/*
* Close the current WAL file, and rename it to the correct filename if it's
* complete.
*
* If segment_complete is true, rename the current WAL file even if we've not
* completed writing the whole segment.
* Close the current WAL file (if open), and rename it to the correct
* filename if it's complete. On failure, prints an error message to stderr
* and returns false, otherwise returns true.
*/
static bool
close_walfile(char *basedir, char *walname, bool segment_complete)
close_walfile(char *basedir, char *partial_suffix)
{
off_t currpos = lseek(walfile, 0, SEEK_CUR);
off_t currpos;
if (walfile == -1)
return true;
currpos = lseek(walfile, 0, SEEK_CUR);
if (currpos == -1)
{
fprintf(stderr,
_("%s: could not determine seek position in file \"%s\": %s\n"),
progname, walname, strerror(errno));
progname, current_walfile_name, strerror(errno));
return false;
}
if (fsync(walfile) != 0)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, walname, strerror(errno));
progname, current_walfile_name, strerror(errno));
return false;
}
if (close(walfile) != 0)
{
fprintf(stderr, _("%s: could not close file \"%s\": %s\n"),
progname, walname, strerror(errno));
progname, current_walfile_name, strerror(errno));
walfile = -1;
return false;
}
@ -153,24 +166,24 @@ close_walfile(char *basedir, char *walname, bool segment_complete)
* Rename the .partial file only if we've completed writing the whole
* segment or segment_complete is true.
*/
if (currpos == XLOG_SEG_SIZE || segment_complete)
if (currpos == XLOG_SEG_SIZE && partial_suffix)
{
char oldfn[MAXPGPATH];
char newfn[MAXPGPATH];
snprintf(oldfn, sizeof(oldfn), "%s/%s.partial", basedir, walname);
snprintf(newfn, sizeof(newfn), "%s/%s", basedir, walname);
snprintf(oldfn, sizeof(oldfn), "%s/%s%s", basedir, current_walfile_name, partial_suffix);
snprintf(newfn, sizeof(newfn), "%s/%s", basedir, current_walfile_name);
if (rename(oldfn, newfn) != 0)
{
fprintf(stderr, _("%s: could not rename file \"%s\": %s\n"),
progname, walname, strerror(errno));
progname, current_walfile_name, strerror(errno));
return false;
}
}
else
else if (partial_suffix)
fprintf(stderr,
_("%s: not renaming \"%s\", segment is not complete\n"),
progname, walname);
_("%s: not renaming \"%s%s\", segment is not complete\n"),
progname, current_walfile_name, partial_suffix);
return true;
}
@ -233,6 +246,123 @@ localTimestampDifferenceExceeds(int64 start_time,
return (diff >= msec * INT64CONST(1000));
}
/*
* Check if a timeline history file exists.
*/
static bool
existsTimeLineHistoryFile(char *basedir, TimeLineID tli)
{
char path[MAXPGPATH];
char histfname[MAXFNAMELEN];
int fd;
/*
* Timeline 1 never has a history file. We treat that as if it existed,
* since we never need to stream it.
*/
if (tli == 1)
return true;
TLHistoryFileName(histfname, tli);
snprintf(path, sizeof(path), "%s/%s", basedir, histfname);
fd = open(path, O_RDONLY | PG_BINARY, 0);
if (fd < 0)
{
if (errno != ENOENT)
fprintf(stderr, _("%s: could not open timeline history file \"%s\": %s"),
progname, path, strerror(errno));
return false;
}
else
{
close(fd);
return true;
}
}
static bool
writeTimeLineHistoryFile(char *basedir, TimeLineID tli, char *filename, char *content)
{
int size = strlen(content);
char path[MAXPGPATH];
char tmppath[MAXPGPATH];
char histfname[MAXFNAMELEN];
int fd;
/*
* Check that the server's idea of how timeline history files should be
* named matches ours.
*/
TLHistoryFileName(histfname, tli);
if (strcmp(histfname, filename) != 0)
{
fprintf(stderr, _("%s: server reported unexpected history file name for timeline %u: %s"),
progname, tli, filename);
return false;
}
/*
* Write into a temp file name.
*/
snprintf(tmppath, MAXPGPATH, "%s.tmp", path);
unlink(tmppath);
fd = open(tmppath, O_WRONLY | O_CREAT | PG_BINARY, S_IRUSR | S_IWUSR);
if (fd < 0)
{
fprintf(stderr, _("%s: could not create timeline history file \"%s\": %s"),
progname, tmppath, strerror(errno));
return false;
}
errno = 0;
if ((int) write(fd, content, size) != size)
{
int save_errno = errno;
/*
* If we fail to make the file, delete it to release disk space
*/
unlink(tmppath);
errno = save_errno;
fprintf(stderr, _("%s: could not write timeline history file \"%s\": %s"),
progname, tmppath, strerror(errno));
return false;
}
if (fsync(fd) != 0)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, tmppath, strerror(errno));
return false;
}
if (close(fd) != 0)
{
fprintf(stderr, _("%s: could not close file \"%s\": %s\n"),
progname, tmppath, strerror(errno));
return false;
}
/*
* Now move the completed history file into place with its final name.
*/
snprintf(path, sizeof(path), "%s/%s", basedir, histfname);
if (rename(tmppath, path) < 0)
{
fprintf(stderr, _("%s: could not rename file \"%s\" to \"%s\": %s\n"),
progname, tmppath, path, strerror(errno));
return false;
}
return true;
}
/*
* Converts an int64 to network byte order.
*/
@ -314,7 +444,8 @@ sendFeedback(PGconn *conn, XLogRecPtr blockpos, int64 now, bool replyRequested)
* (by sending an extra IDENTIFY_SYSTEM command)
*
* All received segments will be written to the directory
* specified by basedir.
* specified by basedir. This will also fetch any missing timeline history
* files.
*
* The stream_stop callback will be called every time data
* is received, and whenever a segment is completed. If it returns
@ -327,20 +458,22 @@ sendFeedback(PGconn *conn, XLogRecPtr blockpos, int64 now, bool replyRequested)
* This message will only contain the write location, and never
* flush or replay.
*
* If 'partial_suffix' is not NULL, files are initially created with the
* given suffix, and the suffix is removed once the file is finished. That
* allows you to tell the difference between partial and completed files,
* so that you can continue later where you left.
*
* Note: The log position *must* be at a log segment start!
*/
bool
ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
char *sysidentifier, char *basedir,
stream_stop_callback stream_stop,
int standby_message_timeout, bool rename_partial)
int standby_message_timeout, char *partial_suffix)
{
char query[128];
char current_walfile_name[MAXPGPATH];
PGresult *res;
char *copybuf = NULL;
int64 last_status = -1;
XLogRecPtr blockpos = InvalidXLogRecPtr;
XLogRecPtr stoppos;
/*
* The message format used in streaming replication changed in 9.3, so we
@ -359,7 +492,7 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
if (sysidentifier != NULL)
{
/* Validate system identifier and timeline hasn't changed */
/* Validate system identifier hasn't changed */
res = PQexec(conn, "IDENTIFY_SYSTEM");
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
@ -385,33 +518,184 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
PQclear(res);
return false;
}
if (timeline != atoi(PQgetvalue(res, 0, 1)))
if (timeline > atoi(PQgetvalue(res, 0, 1)))
{
fprintf(stderr,
_("%s: timeline does not match between base backup and streaming connection\n"),
progname);
_("%s: starting timeline %u is not present in the server\n"),
progname, timeline);
PQclear(res);
return false;
}
PQclear(res);
}
/* Initiate the replication stream at specified location */
snprintf(query, sizeof(query), "START_REPLICATION %X/%X",
(uint32) (startpos >> 32), (uint32) startpos);
res = PQexec(conn, query);
if (PQresultStatus(res) != PGRES_COPY_BOTH)
while (1)
{
fprintf(stderr, _("%s: could not send replication command \"%s\": %s"),
progname, "START_REPLICATION", PQresultErrorMessage(res));
PQclear(res);
return false;
}
PQclear(res);
/*
* Fetch the timeline history file for this timeline, if we don't
* have it already.
*/
if (!existsTimeLineHistoryFile(basedir, timeline))
{
snprintf(query, sizeof(query), "TIMELINE_HISTORY %u", timeline);
res = PQexec(conn, query);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
/* FIXME: we might send it ok, but get an error */
fprintf(stderr, _("%s: could not send replication command \"%s\": %s"),
progname, "TIMELINE_HISTORY", PQresultErrorMessage(res));
PQclear(res);
return false;
}
/*
* The response to TIMELINE_HISTORY is a single row result set
* with two fields: filename and content
*/
if (PQnfields(res) != 2 || PQntuples(res) != 1)
{
fprintf(stderr,
_("%s: unexpected response to TIMELINE_HISTORY command: got %d rows and %d fields, expected %d rows and %d fields\n"),
progname, PQntuples(res), PQnfields(res), 1, 2);
}
/* Write the history file to disk */
writeTimeLineHistoryFile(basedir, timeline,
PQgetvalue(res, 0, 0),
PQgetvalue(res, 0, 1));
PQclear(res);
}
/*
* Before we start streaming from the requested location, check
* if the callback tells us to stop here.
*/
if (stream_stop(startpos, timeline, false))
return true;
/* Initiate the replication stream at specified location */
snprintf(query, sizeof(query), "START_REPLICATION %X/%X TIMELINE %u",
(uint32) (startpos >> 32), (uint32) startpos,
timeline);
res = PQexec(conn, query);
if (PQresultStatus(res) != PGRES_COPY_BOTH)
{
fprintf(stderr, _("%s: could not send replication command \"%s\": %s"),
progname, "START_REPLICATION", PQresultErrorMessage(res));
PQclear(res);
return false;
}
PQclear(res);
/* Stream the WAL */
if (!HandleCopyStream(conn, startpos, timeline, basedir, stream_stop,
standby_message_timeout, partial_suffix,
&stoppos))
goto error;
/*
* Streaming finished.
*
* There are two possible reasons for that: a controlled shutdown,
* or we reached the end of the current timeline. In case of
* end-of-timeline, the server sends a result set after Copy has
* finished, containing the next timeline's ID. Read that, and
* restart streaming from the next timeline.
*/
res = PQgetResult(conn);
if (PQresultStatus(res) == PGRES_TUPLES_OK)
{
/*
* End-of-timeline. Read the next timeline's ID.
*/
uint32 newtimeline;
newtimeline = atoi(PQgetvalue(res, 0, 0));
PQclear(res);
if (newtimeline <= timeline)
{
/* shouldn't happen */
fprintf(stderr,
"server reported unexpected next timeline %u, following timeline %u\n",
newtimeline, timeline);
goto error;
}
/* Read the final result, which should be CommandComplete. */
res = PQgetResult(conn);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr,
_("%s: unexpected termination of replication stream: %s"),
progname, PQresultErrorMessage(res));
goto error;
}
PQclear(res);
/*
* Loop back to start streaming from the new timeline.
* Always start streaming at the beginning of a segment.
*/
timeline = newtimeline;
startpos = stoppos - (stoppos % XLOG_SEG_SIZE);
continue;
}
else if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
/*
* End of replication (ie. controlled shut down of the server).
*
* Check if the callback thinks it's OK to stop here. If not,
* complain.
*/
if (stream_stop(stoppos, timeline, false))
return true;
else
{
fprintf(stderr, _("%s: replication stream was terminated before stop point\n"),
progname);
goto error;
}
}
else
{
/* Server returned an error. */
fprintf(stderr,
_("%s: unexpected termination of replication stream: %s"),
progname, PQresultErrorMessage(res));
goto error;
}
}
error:
if (walfile != -1 && close(walfile) != 0)
fprintf(stderr, _("%s: could not close file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
walfile = -1;
return false;
}
/*
* The main loop of ReceiveXLogStream. Handles the COPY stream after
* initiating streaming with the START_STREAMING command.
*
* If the COPY ends normally, returns true and sets *stoppos to the last
* byte written. On error, returns false.
*/
static bool
HandleCopyStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
char *basedir, stream_stop_callback stream_stop,
int standby_message_timeout, char *partial_suffix,
XLogRecPtr *stoppos)
{
char *copybuf = NULL;
int64 last_status = -1;
XLogRecPtr blockpos = startpos;
bool still_sending = true;
/*
* Receive the actual xlog data
*/
while (1)
{
int r;
@ -430,20 +714,27 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
/*
* Check if we should continue streaming, or abort at this point.
*/
if (stream_stop && stream_stop(blockpos, timeline, false))
if (still_sending && stream_stop(blockpos, timeline, false))
{
if (walfile != -1 && !close_walfile(basedir, current_walfile_name,
rename_partial))
if (!close_walfile(basedir, partial_suffix))
{
/* Potential error message is written by close_walfile */
goto error;
return true;
}
if (PQputCopyEnd(conn, NULL) <= 0 || PQflush(conn))
{
fprintf(stderr, _("%s: could not send copy-end packet: %s"),
progname, PQerrorMessage(conn));
goto error;
}
still_sending = false;
}
/*
* Potentially send a status message to the master
*/
now = localGetCurrentTimestamp();
if (standby_message_timeout > 0 &&
if (still_sending && standby_message_timeout > 0 &&
localTimestampDifferenceExceeds(last_status, now,
standby_message_timeout))
{
@ -457,9 +748,8 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
if (r == 0)
{
/*
* In async mode, and no data available. We block on reading but
* not more than the specified timeout, so that we can send a
* response back to the client.
* No data available. Wait for some to appear, but not longer
* than the specified timeout, so that we can ping the server.
*/
fd_set input_mask;
struct timeval timeout;
@ -467,7 +757,7 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
FD_ZERO(&input_mask);
FD_SET(PQsocket(conn), &input_mask);
if (standby_message_timeout)
if (standby_message_timeout && still_sending)
{
int64 targettime;
long secs;
@ -493,8 +783,8 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
{
/*
* Got a timeout or signal. Continue the loop and either
* deliver a status packet to the server or just go back into
* blocking.
* deliver a status packet to the server or just go back
* into blocking.
*/
continue;
}
@ -515,8 +805,31 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
continue;
}
if (r == -1)
/* End of copy stream */
break;
{
/*
* The server closed its end of the copy stream. Close ours
* if we haven't done so already, and exit.
*/
if (still_sending)
{
if (!close_walfile(basedir, partial_suffix))
{
/* Error message written in close_walfile() */
goto error;
}
if (PQputCopyEnd(conn, NULL) <= 0 || PQflush(conn))
{
fprintf(stderr, _("%s: could not send copy-end packet: %s"),
progname, PQerrorMessage(conn));
goto error;
}
still_sending = false;
}
if (copybuf != NULL)
PQfreemem(copybuf);
*stoppos = blockpos;
return true;
}
if (r == -2)
{
fprintf(stderr, _("%s: could not read COPY data: %s"),
@ -548,174 +861,148 @@ ReceiveXlogStream(PGconn *conn, XLogRecPtr startpos, uint32 timeline,
replyRequested = copybuf[pos];
/* If the server requested an immediate reply, send one. */
if (replyRequested)
if (replyRequested && still_sending)
{
now = localGetCurrentTimestamp();
if (!sendFeedback(conn, blockpos, now, false))
goto error;
last_status = now;
}
continue;
}
else if (copybuf[0] != 'w')
else if (copybuf[0] == 'w')
{
/*
* Once we've decided we don't want to receive any more, just
* ignore any subsequent XLogData messages.
*/
if (!still_sending)
continue;
/*
* Read the header of the XLogData message, enclosed in the
* CopyData message. We only need the WAL location field
* (dataStart), the rest of the header is ignored.
*/
hdr_len = 1; /* msgtype 'w' */
hdr_len += 8; /* dataStart */
hdr_len += 8; /* walEnd */
hdr_len += 8; /* sendTime */
if (r < hdr_len + 1)
{
fprintf(stderr, _("%s: streaming header too small: %d\n"),
progname, r);
goto error;
}
blockpos = recvint64(&copybuf[1]);
/* Extract WAL location for this block */
xlogoff = blockpos % XLOG_SEG_SIZE;
/*
* Verify that the initial location in the stream matches where
* we think we are.
*/
if (walfile == -1)
{
/* No file open yet */
if (xlogoff != 0)
{
fprintf(stderr,
_("%s: received transaction log record for offset %u with no file open\n"),
progname, xlogoff);
goto error;
}
}
else
{
/* More data in existing segment */
/* XXX: store seek value don't reseek all the time */
if (lseek(walfile, 0, SEEK_CUR) != xlogoff)
{
fprintf(stderr,
_("%s: got WAL data offset %08x, expected %08x\n"),
progname, xlogoff, (int) lseek(walfile, 0, SEEK_CUR));
goto error;
}
}
bytes_left = r - hdr_len;
bytes_written = 0;
while (bytes_left)
{
int bytes_to_write;
/*
* If crossing a WAL boundary, only write up until we reach
* XLOG_SEG_SIZE.
*/
if (xlogoff + bytes_left > XLOG_SEG_SIZE)
bytes_to_write = XLOG_SEG_SIZE - xlogoff;
else
bytes_to_write = bytes_left;
if (walfile == -1)
{
if (!open_walfile(blockpos, timeline,
basedir, partial_suffix))
{
/* Error logged by open_walfile */
goto error;
}
}
if (write(walfile,
copybuf + hdr_len + bytes_written,
bytes_to_write) != bytes_to_write)
{
fprintf(stderr,
_("%s: could not write %u bytes to WAL file \"%s\": %s\n"),
progname, bytes_to_write, current_walfile_name,
strerror(errno));
goto error;
}
/* Write was successful, advance our position */
bytes_written += bytes_to_write;
bytes_left -= bytes_to_write;
blockpos += bytes_to_write;
xlogoff += bytes_to_write;
/* Did we reach the end of a WAL segment? */
if (blockpos % XLOG_SEG_SIZE == 0)
{
if (!close_walfile(basedir, partial_suffix))
/* Error message written in close_walfile() */
goto error;
xlogoff = 0;
if (still_sending && stream_stop(blockpos, timeline, false))
{
if (PQputCopyEnd(conn, NULL) <= 0 || PQflush(conn))
{
fprintf(stderr, _("%s: could not send copy-end packet: %s"),
progname, PQerrorMessage(conn));
goto error;
}
still_sending = false;
break; /* ignore the rest of this XLogData packet */
}
}
}
/* No more data left to write, receive next copy packet */
}
else
{
fprintf(stderr, _("%s: unrecognized streaming header: \"%c\"\n"),
progname, copybuf[0]);
goto error;
}
/*
* Read the header of the XLogData message, enclosed in the CopyData
* message. We only need the WAL location field (dataStart), the rest
* of the header is ignored.
*/
hdr_len = 1; /* msgtype 'w' */
hdr_len += 8; /* dataStart */
hdr_len += 8; /* walEnd */
hdr_len += 8; /* sendTime */
if (r < hdr_len + 1)
{
fprintf(stderr, _("%s: streaming header too small: %d\n"),
progname, r);
goto error;
}
blockpos = recvint64(&copybuf[1]);
/* Extract WAL location for this block */
xlogoff = blockpos % XLOG_SEG_SIZE;
/*
* Verify that the initial location in the stream matches where we
* think we are.
*/
if (walfile == -1)
{
/* No file open yet */
if (xlogoff != 0)
{
fprintf(stderr,
_("%s: received transaction log record for offset %u with no file open\n"),
progname, xlogoff);
goto error;
}
}
else
{
/* More data in existing segment */
/* XXX: store seek value don't reseek all the time */
if (lseek(walfile, 0, SEEK_CUR) != xlogoff)
{
fprintf(stderr,
_("%s: got WAL data offset %08x, expected %08x\n"),
progname, xlogoff, (int) lseek(walfile, 0, SEEK_CUR));
goto error;
}
}
bytes_left = r - hdr_len;
bytes_written = 0;
while (bytes_left)
{
int bytes_to_write;
/*
* If crossing a WAL boundary, only write up until we reach
* XLOG_SEG_SIZE.
*/
if (xlogoff + bytes_left > XLOG_SEG_SIZE)
bytes_to_write = XLOG_SEG_SIZE - xlogoff;
else
bytes_to_write = bytes_left;
if (walfile == -1)
{
walfile = open_walfile(blockpos, timeline,
basedir, current_walfile_name);
if (walfile == -1)
/* Error logged by open_walfile */
goto error;
}
if (write(walfile,
copybuf + hdr_len + bytes_written,
bytes_to_write) != bytes_to_write)
{
fprintf(stderr,
_("%s: could not write %u bytes to WAL file \"%s\": %s\n"),
progname, bytes_to_write, current_walfile_name,
strerror(errno));
goto error;
}
/* Write was successful, advance our position */
bytes_written += bytes_to_write;
bytes_left -= bytes_to_write;
blockpos += bytes_to_write;
xlogoff += bytes_to_write;
/* Did we reach the end of a WAL segment? */
if (blockpos % XLOG_SEG_SIZE == 0)
{
if (!close_walfile(basedir, current_walfile_name, false))
/* Error message written in close_walfile() */
goto error;
xlogoff = 0;
if (stream_stop != NULL)
{
/*
* Callback when the segment finished, and return if it
* told us to.
*/
if (stream_stop(blockpos, timeline, true))
return true;
}
}
}
/* No more data left to write, start receiving next copy packet */
}
/*
* The only way to get out of the loop is if the server shut down the
* replication stream. If it's a controlled shutdown, the server will send
* a shutdown message, and we'll return the latest xlog location that has
* been streamed.
*/
res = PQgetResult(conn);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr,
_("%s: unexpected termination of replication stream: %s"),
progname, PQresultErrorMessage(res));
goto error;
}
PQclear(res);
/* Complain if we've not reached stop point yet */
if (stream_stop != NULL && !stream_stop(blockpos, timeline, false))
{
fprintf(stderr, _("%s: replication stream was terminated before stop point\n"),
progname);
goto error;
}
if (copybuf != NULL)
PQfreemem(copybuf);
if (walfile != -1 && close(walfile) != 0)
fprintf(stderr, _("%s: could not close file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
walfile = -1;
return true;
error:
if (copybuf != NULL)
PQfreemem(copybuf);
if (walfile != -1 && close(walfile) != 0)
fprintf(stderr, _("%s: could not close file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
walfile = -1;
return false;
}