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https://github.com/postgres/postgres.git
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Move basebackup code to new directory src/backend/backup
Reviewed by David Steele and Justin Pryzby Discussion: http://postgr.es/m/CA+TgmoafqboATDSoXHz8VLrSwK_MDhjthK4hEpYjqf9_1Fmczw%40mail.gmail.com
This commit is contained in:
Robert Haas
309
src/backend/backup/basebackup_server.c
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309
src/backend/backup/basebackup_server.c
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/*-------------------------------------------------------------------------
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*
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* basebackup_server.c
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* store basebackup archives on the server
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*
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* IDENTIFICATION
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* src/backend/backup/basebackup_server.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "access/xact.h"
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#include "backup/basebackup.h"
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#include "backup/basebackup_sink.h"
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#include "catalog/pg_authid.h"
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#include "miscadmin.h"
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#include "storage/fd.h"
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#include "utils/acl.h"
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#include "utils/timestamp.h"
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#include "utils/wait_event.h"
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typedef struct bbsink_server
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{
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/* Common information for all types of sink. */
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bbsink base;
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/* Directory in which backup is to be stored. */
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char *pathname;
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/* Currently open file (or 0 if nothing open). */
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File file;
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/* Current file position. */
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off_t filepos;
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} bbsink_server;
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static void bbsink_server_begin_archive(bbsink *sink,
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const char *archive_name);
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static void bbsink_server_archive_contents(bbsink *sink, size_t len);
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static void bbsink_server_end_archive(bbsink *sink);
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static void bbsink_server_begin_manifest(bbsink *sink);
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static void bbsink_server_manifest_contents(bbsink *sink, size_t len);
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static void bbsink_server_end_manifest(bbsink *sink);
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static const bbsink_ops bbsink_server_ops = {
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.begin_backup = bbsink_forward_begin_backup,
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.begin_archive = bbsink_server_begin_archive,
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.archive_contents = bbsink_server_archive_contents,
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.end_archive = bbsink_server_end_archive,
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.begin_manifest = bbsink_server_begin_manifest,
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.manifest_contents = bbsink_server_manifest_contents,
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.end_manifest = bbsink_server_end_manifest,
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.end_backup = bbsink_forward_end_backup,
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.cleanup = bbsink_forward_cleanup
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};
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/*
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* Create a new 'server' bbsink.
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*/
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bbsink *
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bbsink_server_new(bbsink *next, char *pathname)
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{
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bbsink_server *sink = palloc0(sizeof(bbsink_server));
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*((const bbsink_ops **) &sink->base.bbs_ops) = &bbsink_server_ops;
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sink->pathname = pathname;
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sink->base.bbs_next = next;
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/* Replication permission is not sufficient in this case. */
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StartTransactionCommand();
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if (!has_privs_of_role(GetUserId(), ROLE_PG_WRITE_SERVER_FILES))
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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errmsg("must be superuser or a role with privileges of the pg_write_server_files role to create server backup")));
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CommitTransactionCommand();
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/*
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* It's not a good idea to store your backups in the same directory that
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* you're backing up. If we allowed a relative path here, that could
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* easily happen accidentally, so we don't. The user could still
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* accomplish the same thing by including the absolute path to $PGDATA in
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* the pathname, but that's likely an intentional bad decision rather than
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* an accident.
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*/
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if (!is_absolute_path(pathname))
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_NAME),
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errmsg("relative path not allowed for server backup")));
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switch (pg_check_dir(pathname))
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{
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case 0:
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/*
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* Does not exist, so create it using the same permissions we'd
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* use for a new subdirectory of the data directory itself.
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*/
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if (MakePGDirectory(pathname) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not create directory \"%s\": %m", pathname)));
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break;
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case 1:
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/* Exists, empty. */
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break;
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case 2:
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case 3:
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case 4:
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/* Exists, not empty. */
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ereport(ERROR,
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(errcode(ERRCODE_DUPLICATE_FILE),
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errmsg("directory \"%s\" exists but is not empty",
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pathname)));
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break;
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default:
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/* Access problem. */
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not access directory \"%s\": %m",
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pathname)));
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}
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return &sink->base;
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}
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/*
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* Open the correct output file for this archive.
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*/
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static void
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bbsink_server_begin_archive(bbsink *sink, const char *archive_name)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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char *filename;
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Assert(mysink->file == 0);
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Assert(mysink->filepos == 0);
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filename = psprintf("%s/%s", mysink->pathname, archive_name);
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mysink->file = PathNameOpenFile(filename,
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O_CREAT | O_EXCL | O_WRONLY | PG_BINARY);
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if (mysink->file <= 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not create file \"%s\": %m", filename)));
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pfree(filename);
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bbsink_forward_begin_archive(sink, archive_name);
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}
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/*
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* Write the data to the output file.
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*/
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static void
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bbsink_server_archive_contents(bbsink *sink, size_t len)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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int nbytes;
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nbytes = FileWrite(mysink->file, mysink->base.bbs_buffer, len,
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mysink->filepos, WAIT_EVENT_BASEBACKUP_WRITE);
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if (nbytes != len)
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{
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if (nbytes < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not write file \"%s\": %m",
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FilePathName(mysink->file)),
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errhint("Check free disk space.")));
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/* short write: complain appropriately */
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ereport(ERROR,
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(errcode(ERRCODE_DISK_FULL),
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errmsg("could not write file \"%s\": wrote only %d of %d bytes at offset %u",
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FilePathName(mysink->file),
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nbytes, (int) len, (unsigned) mysink->filepos),
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errhint("Check free disk space.")));
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}
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mysink->filepos += nbytes;
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bbsink_forward_archive_contents(sink, len);
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}
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/*
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* fsync and close the current output file.
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*/
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static void
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bbsink_server_end_archive(bbsink *sink)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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/*
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* We intentionally don't use data_sync_elevel here, because the server
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* shouldn't PANIC just because we can't guarantee that the backup has
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* been written down to disk. Running recovery won't fix anything in this
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* case anyway.
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*/
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if (FileSync(mysink->file, WAIT_EVENT_BASEBACKUP_SYNC) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not fsync file \"%s\": %m",
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FilePathName(mysink->file))));
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/* We're done with this file now. */
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FileClose(mysink->file);
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mysink->file = 0;
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mysink->filepos = 0;
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bbsink_forward_end_archive(sink);
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}
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/*
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* Open the output file to which we will write the manifest.
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*
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* Just like pg_basebackup, we write the manifest first under a temporary
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* name and then rename it into place after fsync. That way, if the manifest
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* is there and under the correct name, the user can be sure that the backup
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* completed.
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*/
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static void
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bbsink_server_begin_manifest(bbsink *sink)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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char *tmp_filename;
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Assert(mysink->file == 0);
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tmp_filename = psprintf("%s/backup_manifest.tmp", mysink->pathname);
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mysink->file = PathNameOpenFile(tmp_filename,
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O_CREAT | O_EXCL | O_WRONLY | PG_BINARY);
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if (mysink->file <= 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not create file \"%s\": %m", tmp_filename)));
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pfree(tmp_filename);
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bbsink_forward_begin_manifest(sink);
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}
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/*
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* Each chunk of manifest data is sent using a CopyData message.
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*/
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static void
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bbsink_server_manifest_contents(bbsink *sink, size_t len)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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int nbytes;
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nbytes = FileWrite(mysink->file, mysink->base.bbs_buffer, len,
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mysink->filepos, WAIT_EVENT_BASEBACKUP_WRITE);
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if (nbytes != len)
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{
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if (nbytes < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not write file \"%s\": %m",
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FilePathName(mysink->file)),
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errhint("Check free disk space.")));
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/* short write: complain appropriately */
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ereport(ERROR,
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(errcode(ERRCODE_DISK_FULL),
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errmsg("could not write file \"%s\": wrote only %d of %d bytes at offset %u",
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FilePathName(mysink->file),
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nbytes, (int) len, (unsigned) mysink->filepos),
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errhint("Check free disk space.")));
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}
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mysink->filepos += nbytes;
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bbsink_forward_manifest_contents(sink, len);
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}
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/*
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* fsync the backup manifest, close the file, and then rename it into place.
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*/
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static void
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bbsink_server_end_manifest(bbsink *sink)
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{
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bbsink_server *mysink = (bbsink_server *) sink;
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char *tmp_filename;
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char *filename;
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/* We're done with this file now. */
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FileClose(mysink->file);
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mysink->file = 0;
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/*
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* Rename it into place. This also fsyncs the temporary file, so we don't
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* need to do that here. We don't use data_sync_elevel here for the same
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* reasons as in bbsink_server_end_archive.
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*/
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tmp_filename = psprintf("%s/backup_manifest.tmp", mysink->pathname);
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filename = psprintf("%s/backup_manifest", mysink->pathname);
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durable_rename(tmp_filename, filename, ERROR);
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pfree(filename);
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pfree(tmp_filename);
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bbsink_forward_end_manifest(sink);
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}
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