Line data Source code
1 : use std::sync::Arc;
2 :
3 : use anyhow::{bail, Result};
4 : use camino::Utf8PathBuf;
5 :
6 : use postgres_ffi::{MAX_SEND_SIZE, WAL_SEGMENT_SIZE};
7 : use tokio::{
8 : fs::OpenOptions,
9 : io::{AsyncSeekExt, AsyncWriteExt},
10 : };
11 : use tracing::{info, warn};
12 : use utils::{id::TenantTimelineId, lsn::Lsn};
13 :
14 : use crate::{
15 : control_file::{FileStorage, Storage},
16 : pull_timeline::{create_temp_timeline_dir, load_temp_timeline, validate_temp_timeline},
17 : state::TimelinePersistentState,
18 : timeline::{Timeline, TimelineError},
19 : wal_backup::copy_s3_segments,
20 : wal_storage::{wal_file_paths, WalReader},
21 : GlobalTimelines, SafeKeeperConf,
22 : };
23 :
24 : // we don't want to have more than 10 segments on disk after copy, because they take space
25 : const MAX_BACKUP_LAG: u64 = 10 * WAL_SEGMENT_SIZE as u64;
26 :
27 : pub struct Request {
28 : pub source: Arc<Timeline>,
29 : pub until_lsn: Lsn,
30 : pub destination_ttid: TenantTimelineId,
31 : }
32 :
33 0 : pub async fn handle_request(request: Request) -> Result<()> {
34 0 : // TODO: request.until_lsn MUST be a valid LSN, and we cannot check it :(
35 0 : // if LSN will point to the middle of a WAL record, timeline will be in "broken" state
36 0 :
37 0 : match GlobalTimelines::get(request.destination_ttid) {
38 : // timeline already exists. would be good to check that this timeline is the copy
39 : // of the source timeline, but it isn't obvious how to do that
40 0 : Ok(_) => return Ok(()),
41 : // timeline not found, we are going to create it
42 0 : Err(TimelineError::NotFound(_)) => {}
43 : // error, probably timeline was deleted
44 0 : res => {
45 0 : res?;
46 : }
47 : }
48 :
49 0 : let conf = &GlobalTimelines::get_global_config();
50 0 : let ttid = request.destination_ttid;
51 :
52 0 : let (_tmp_dir, tli_dir_path) = create_temp_timeline_dir(conf, ttid).await?;
53 :
54 0 : let (mem_state, state) = request.source.get_state().await;
55 0 : let start_lsn = state.timeline_start_lsn;
56 0 : if start_lsn == Lsn::INVALID {
57 0 : bail!("timeline is not initialized");
58 0 : }
59 0 : let backup_lsn = mem_state.backup_lsn;
60 0 :
61 0 : {
62 0 : let commit_lsn = mem_state.commit_lsn;
63 0 : let flush_lsn = request.source.get_flush_lsn().await;
64 :
65 0 : info!(
66 0 : "collected info about source timeline: start_lsn={}, backup_lsn={}, commit_lsn={}, flush_lsn={}",
67 0 : start_lsn, backup_lsn, commit_lsn, flush_lsn
68 0 : );
69 :
70 0 : assert!(backup_lsn >= start_lsn);
71 0 : assert!(commit_lsn >= start_lsn);
72 0 : assert!(flush_lsn >= start_lsn);
73 :
74 0 : if request.until_lsn > flush_lsn {
75 0 : bail!("requested LSN is beyond the end of the timeline");
76 0 : }
77 0 : if request.until_lsn < start_lsn {
78 0 : bail!("requested LSN is before the start of the timeline");
79 0 : }
80 0 :
81 0 : if request.until_lsn > commit_lsn {
82 0 : warn!("copy_timeline WAL is not fully committed");
83 0 : }
84 :
85 0 : if backup_lsn < request.until_lsn && request.until_lsn.0 - backup_lsn.0 > MAX_BACKUP_LAG {
86 : // we have a lot of segments that are not backed up. we can try to wait here until
87 : // segments will be backed up to remote storage, but it's not clear how long to wait
88 0 : bail!("too many segments are not backed up");
89 0 : }
90 0 : }
91 0 :
92 0 : let wal_seg_size = state.server.wal_seg_size as usize;
93 0 : if wal_seg_size == 0 {
94 0 : bail!("wal_seg_size is not set");
95 0 : }
96 0 :
97 0 : let first_segment = start_lsn.segment_number(wal_seg_size);
98 0 : let last_segment = request.until_lsn.segment_number(wal_seg_size);
99 :
100 0 : let new_backup_lsn = {
101 : // we can't have new backup_lsn greater than existing backup_lsn or start of the last segment
102 0 : let max_backup_lsn = backup_lsn.min(Lsn(last_segment * wal_seg_size as u64));
103 0 :
104 0 : if max_backup_lsn <= start_lsn {
105 : // probably we are starting from the first segment, which was not backed up yet.
106 : // note that start_lsn can be in the middle of the segment
107 0 : start_lsn
108 : } else {
109 : // we have some segments backed up, so we will assume all WAL below max_backup_lsn is backed up
110 0 : assert!(max_backup_lsn.segment_offset(wal_seg_size) == 0);
111 0 : max_backup_lsn
112 : }
113 : };
114 :
115 : // all previous segments will be copied inside S3
116 0 : let first_ondisk_segment = new_backup_lsn.segment_number(wal_seg_size);
117 0 : assert!(first_ondisk_segment <= last_segment);
118 0 : assert!(first_ondisk_segment >= first_segment);
119 :
120 0 : copy_s3_segments(
121 0 : wal_seg_size,
122 0 : &request.source.ttid,
123 0 : &request.destination_ttid,
124 0 : first_segment,
125 0 : first_ondisk_segment,
126 0 : )
127 0 : .await?;
128 :
129 0 : copy_disk_segments(
130 0 : conf,
131 0 : &state,
132 0 : wal_seg_size,
133 0 : &request.source.ttid,
134 0 : new_backup_lsn,
135 0 : request.until_lsn,
136 0 : &tli_dir_path,
137 0 : )
138 0 : .await?;
139 :
140 0 : let mut new_state = TimelinePersistentState::new(
141 0 : &request.destination_ttid,
142 0 : state.server.clone(),
143 0 : vec![],
144 0 : request.until_lsn,
145 0 : start_lsn,
146 0 : );
147 0 : new_state.timeline_start_lsn = start_lsn;
148 0 : new_state.peer_horizon_lsn = request.until_lsn;
149 0 : new_state.backup_lsn = new_backup_lsn;
150 :
151 0 : let mut file_storage = FileStorage::create_new(tli_dir_path.clone(), conf, new_state.clone())?;
152 0 : file_storage.persist(&new_state).await?;
153 :
154 : // now we have a ready timeline in a temp directory
155 0 : validate_temp_timeline(conf, request.destination_ttid, &tli_dir_path).await?;
156 0 : load_temp_timeline(conf, request.destination_ttid, &tli_dir_path).await?;
157 :
158 0 : Ok(())
159 0 : }
160 :
161 0 : async fn copy_disk_segments(
162 0 : conf: &SafeKeeperConf,
163 0 : persisted_state: &TimelinePersistentState,
164 0 : wal_seg_size: usize,
165 0 : source_ttid: &TenantTimelineId,
166 0 : start_lsn: Lsn,
167 0 : end_lsn: Lsn,
168 0 : tli_dir_path: &Utf8PathBuf,
169 0 : ) -> Result<()> {
170 0 : let mut wal_reader = WalReader::new(
171 0 : conf.workdir.clone(),
172 0 : conf.timeline_dir(source_ttid),
173 0 : persisted_state,
174 0 : start_lsn,
175 0 : true,
176 0 : )?;
177 :
178 0 : let mut buf = [0u8; MAX_SEND_SIZE];
179 0 :
180 0 : let first_segment = start_lsn.segment_number(wal_seg_size);
181 0 : let last_segment = end_lsn.segment_number(wal_seg_size);
182 :
183 0 : for segment in first_segment..=last_segment {
184 0 : let segment_start = segment * wal_seg_size as u64;
185 0 : let segment_end = segment_start + wal_seg_size as u64;
186 0 :
187 0 : let copy_start = segment_start.max(start_lsn.0);
188 0 : let copy_end = segment_end.min(end_lsn.0);
189 0 :
190 0 : let copy_start = copy_start - segment_start;
191 0 : let copy_end = copy_end - segment_start;
192 :
193 0 : let wal_file_path = {
194 0 : let (normal, partial) = wal_file_paths(tli_dir_path, segment, wal_seg_size)?;
195 :
196 0 : if segment == last_segment {
197 0 : partial
198 : } else {
199 0 : normal
200 : }
201 : };
202 :
203 0 : write_segment(
204 0 : &mut buf,
205 0 : &wal_file_path,
206 0 : wal_seg_size as u64,
207 0 : copy_start,
208 0 : copy_end,
209 0 : &mut wal_reader,
210 0 : )
211 0 : .await?;
212 : }
213 :
214 0 : Ok(())
215 0 : }
216 :
217 0 : async fn write_segment(
218 0 : buf: &mut [u8],
219 0 : file_path: &Utf8PathBuf,
220 0 : wal_seg_size: u64,
221 0 : from: u64,
222 0 : to: u64,
223 0 : reader: &mut WalReader,
224 0 : ) -> Result<()> {
225 0 : assert!(from <= to);
226 0 : assert!(to <= wal_seg_size);
227 :
228 0 : let mut file = OpenOptions::new()
229 0 : .create(true)
230 0 : .write(true)
231 0 : .open(&file_path)
232 0 : .await?;
233 :
234 : // maybe fill with zeros, as in wal_storage.rs?
235 0 : file.set_len(wal_seg_size).await?;
236 0 : file.seek(std::io::SeekFrom::Start(from)).await?;
237 :
238 0 : let mut bytes_left = to - from;
239 0 : while bytes_left > 0 {
240 0 : let len = bytes_left as usize;
241 0 : let len = len.min(buf.len());
242 0 : let len = reader.read(&mut buf[..len]).await?;
243 0 : file.write_all(&buf[..len]).await?;
244 0 : bytes_left -= len as u64;
245 : }
246 :
247 0 : file.flush().await?;
248 0 : file.sync_all().await?;
249 0 : Ok(())
250 0 : }
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