/*
* Load all replication slots from disk into memory at server startup. This
* needs to be run before we start crash recovery.
*/
void
StartupReplicationSlots(void)
{
DIR *replication_dir;
struct dirent *replication_de;
elog(DEBUG1, "starting up replication slots");
/* restore all slots by iterating over all on-disk entries */
replication_dir = AllocateDir("pg_replslot");
while ((replication_de = ReadDir(replication_dir, "pg_replslot")) != NULL)
{
struct stat statbuf;
char path[MAXPGPATH + 12];
if (strcmp(replication_de->d_name, ".") == 0 ||
strcmp(replication_de->d_name, "..") == 0)
continue;
snprintf(path, sizeof(path), "pg_replslot/%s", replication_de->d_name);
/* we're only creating directories here, skip if it's not our's */
if (lstat(path, &statbuf) == 0 && !S_ISDIR(statbuf.st_mode))
continue;
/* we crashed while a slot was being setup or deleted, clean up */
if (pg_str_endswith(replication_de->d_name, ".tmp"))
{
if (!rmtree(path, true))
{
ereport(WARNING,
(errcode_for_file_access(),
errmsg("could not remove directory \"%s\"", path)));
continue;
}
fsync_fname("pg_replslot", true);
continue;
}
/* looks like a slot in a normal state, restore */
RestoreSlotFromDisk(replication_de->d_name);
}
FreeDir(replication_dir);
/* currently no slots exist, we're done. */
if (max_replication_slots <= 0)
return;
/* Now that we have recovered all the data, compute replication xmin */
ReplicationSlotsComputeRequiredXmin(false);
ReplicationSlotsComputeRequiredLSN();
}
/*
* Callback for processing source file list.
*
* This is called once for every file in the source server. We decide what
* action needs to be taken for the file, depending on whether the file
* exists in the target and whether the size matches.
*/
void
process_source_file(const char *path, file_type_t type, size_t newsize,
const char *link_target)
{
bool exists;
char localpath[MAXPGPATH];
struct stat statbuf;
filemap_t *map = filemap;
file_action_t action = FILE_ACTION_NONE;
size_t oldsize = 0;
file_entry_t *entry;
Assert(map->array == NULL);
/*
* Completely ignore some special files in source and destination.
*/
if (strcmp(path, "postmaster.pid") == 0 ||
strcmp(path, "postmaster.opts") == 0)
return;
/*
* Skip temporary files, .../pgsql_tmp/... and .../pgsql_tmp.* in source.
* This has the effect that all temporary files in the destination will be
* removed.
*/
if (strstr(path, "/" PG_TEMP_FILE_PREFIX) != NULL)
return;
if (strstr(path, "/" PG_TEMP_FILES_DIR "/") != NULL)
return;
/*
* sanity check: a filename that looks like a data file better be a
* regular file
*/
if (type != FILE_TYPE_REGULAR && isRelDataFile(path))
pg_fatal("data file in source \"%s\" is not a regular file\n", path);
snprintf(localpath, sizeof(localpath), "%s/%s", datadir_target, path);
/* Does the corresponding file exist in the target data dir? */
if (lstat(localpath, &statbuf) < 0)
{
if (errno != ENOENT)
pg_fatal("could not stat file \"%s\": %s\n",
localpath, strerror(errno));
exists = false;
}
else
exists = true;
switch (type)
{
case FILE_TYPE_DIRECTORY:
if (exists && !S_ISDIR(statbuf.st_mode))
{
/* it's a directory in source, but not in target. Strange.. */
pg_fatal("\"%s\" is not a directory\n", localpath);
}
if (!exists)
action = FILE_ACTION_CREATE;
else
action = FILE_ACTION_NONE;
oldsize = 0;
break;
case FILE_TYPE_SYMLINK:
if (exists &&
#ifndef WIN32
!S_ISLNK(statbuf.st_mode)
#else
!pgwin32_is_junction(localpath)
#endif
)
{
/*
* It's a symbolic link in source, but not in target.
* Strange..
*/
pg_fatal("\"%s\" is not a symbolic link\n", localpath);
}
if (!exists)
action = FILE_ACTION_CREATE;
else
action = FILE_ACTION_NONE;
oldsize = 0;
break;
case FILE_TYPE_REGULAR:
if (exists && !S_ISREG(statbuf.st_mode))
pg_fatal("\"%s\" is not a regular file\n", localpath);
if (!exists || !isRelDataFile(path))
{
/*
* File exists in source, but not in target. Or it's a
* non-data file that we have no special processing for. Copy
* it in toto.
*
* An exception: PG_VERSIONs should be identical, but avoid
* overwriting it for paranoia.
*/
if (pg_str_endswith(path, "PG_VERSION"))
{
action = FILE_ACTION_NONE;
oldsize = statbuf.st_size;
}
else
{
action = FILE_ACTION_COPY;
oldsize = 0;
}
}
else
{
/*
* It's a data file that exists in both.
*
* If it's larger in target, we can truncate it. There will
* also be a WAL record of the truncation in the source
* system, so WAL replay would eventually truncate the target
* too, but we might as well do it now.
*
* If it's smaller in the target, it means that it has been
* truncated in the target, or enlarged in the source, or
* both. If it was truncated in the target, we need to copy
* the missing tail from the source system. If it was enlarged
* in the source system, there will be WAL records in the
* source system for the new blocks, so we wouldn't need to
* copy them here. But we don't know which scenario we're
* dealing with, and there's no harm in copying the missing
* blocks now, so do it now.
*
* If it's the same size, do nothing here. Any blocks modified
* in the target will be copied based on parsing the target
* system's WAL, and any blocks modified in the source will be
* updated after rewinding, when the source system's WAL is
* replayed.
*/
oldsize = statbuf.st_size;
if (oldsize < newsize)
action = FILE_ACTION_COPY_TAIL;
else if (oldsize > newsize)
action = FILE_ACTION_TRUNCATE;
else
action = FILE_ACTION_NONE;
}
break;
}
/* Create a new entry for this file */
entry = pg_malloc(sizeof(file_entry_t));
entry->path = pg_strdup(path);
entry->type = type;
entry->action = action;
entry->oldsize = oldsize;
entry->newsize = newsize;
entry->link_target = link_target ? pg_strdup(link_target) : NULL;
entry->next = NULL;
entry->pagemap.bitmap = NULL;
entry->pagemap.bitmapsize = 0;
entry->isrelfile = isRelDataFile(path);
if (map->last)
{
map->last->next = entry;
map->last = entry;
}
else
map->first = map->last = entry;
map->nlist++;
}
