Implement page servise 'fullbackup' endpoint (#1923)

* Implement page servise 'fullbackup' endpoint that works like basebackup, but also sends relational files

* Add test_runner/batch_others/test_fullbackup.py

Co-authored-by: bojanserafimov <bojan.serafimov7@gmail.com>

pageserver/src/basebackup.rs

@@ -13,6 +13,7 @@
 use anyhow::{anyhow, bail, ensure, Context, Result};
 use bytes::{BufMut, BytesMut};
 use fail::fail_point;
+use itertools::Itertools;
 use std::fmt::Write as FmtWrite;
 use std::io;
 use std::io::Write;
@@ -21,7 +22,7 @@ use std::time::SystemTime;
 use tar::{Builder, EntryType, Header};
 use tracing::*;
 
-use crate::reltag::SlruKind;
+use crate::reltag::{RelTag, SlruKind};
 use crate::repository::Timeline;
 use crate::DatadirTimelineImpl;
 use postgres_ffi::xlog_utils::*;
@@ -39,11 +40,12 @@ where
     timeline: &'a Arc<DatadirTimelineImpl>,
     pub lsn: Lsn,
     prev_record_lsn: Lsn,
-
+    full_backup: bool,
     finished: bool,
 }
 
-// Create basebackup with non-rel data in it. Omit relational data.
+// Create basebackup with non-rel data in it.
+// Only include relational data if 'full_backup' is true.
 //
 // Currently we use empty lsn in two cases:
 //  * During the basebackup right after timeline creation
@@ -58,6 +60,7 @@ where
         write: W,
         timeline: &'a Arc<DatadirTimelineImpl>,
         req_lsn: Option<Lsn>,
+        full_backup: bool,
     ) -> Result<Basebackup<'a, W>> {
         // Compute postgres doesn't have any previous WAL files, but the first
         // record that it's going to write needs to include the LSN of the
@@ -94,8 +97,8 @@ where
         };
 
         info!(
-            "taking basebackup lsn={}, prev_lsn={}",
-            backup_lsn, backup_prev
+            "taking basebackup lsn={}, prev_lsn={} (full_backup={})",
+            backup_lsn, backup_prev, full_backup
         );
 
         Ok(Basebackup {
@@ -103,6 +106,7 @@ where
             timeline,
             lsn: backup_lsn,
             prev_record_lsn: backup_prev,
+            full_backup,
             finished: false,
         })
     }
@@ -140,6 +144,13 @@ where
         // Create tablespace directories
         for ((spcnode, dbnode), has_relmap_file) in self.timeline.list_dbdirs(self.lsn)? {
             self.add_dbdir(spcnode, dbnode, has_relmap_file)?;
+
+            // Gather and send relational files in each database if full backup is requested.
+            if self.full_backup {
+                for rel in self.timeline.list_rels(spcnode, dbnode, self.lsn)? {
+                    self.add_rel(rel)?;
+                }
+            }
         }
         for xid in self.timeline.list_twophase_files(self.lsn)? {
             self.add_twophase_file(xid)?;
@@ -157,6 +168,38 @@ where
         Ok(())
     }
 
+    fn add_rel(&mut self, tag: RelTag) -> anyhow::Result<()> {
+        let nblocks = self.timeline.get_rel_size(tag, self.lsn)?;
+
+        // Function that adds relation segment data to archive
+        let mut add_file = |segment_index, data: &Vec<u8>| -> anyhow::Result<()> {
+            let file_name = tag.to_segfile_name(segment_index as u32);
+            let header = new_tar_header(&file_name, data.len() as u64)?;
+            self.ar.append(&header, data.as_slice())?;
+            Ok(())
+        };
+
+        // If the relation is empty, create an empty file
+        if nblocks == 0 {
+            add_file(0, &vec![])?;
+            return Ok(());
+        }
+
+        // Add a file for each chunk of blocks (aka segment)
+        let chunks = (0..nblocks).chunks(pg_constants::RELSEG_SIZE as usize);
+        for (seg, blocks) in chunks.into_iter().enumerate() {
+            let mut segment_data: Vec<u8> = vec![];
+            for blknum in blocks {
+                let img = self.timeline.get_rel_page_at_lsn(tag, blknum, self.lsn)?;
+                segment_data.extend_from_slice(&img[..]);
+            }
+
+            add_file(seg, &segment_data)?;
+        }
+
+        Ok(())
+    }
+
     //
     // Generate SLRU segment files from repository.
     //
@@ -312,21 +355,24 @@ where
         pg_control.checkPointCopy = checkpoint;
         pg_control.state = pg_constants::DB_SHUTDOWNED;
 
-        // add zenith.signal file
-        let mut zenith_signal = String::new();
-        if self.prev_record_lsn == Lsn(0) {
-            if self.lsn == self.timeline.tline.get_ancestor_lsn() {
-                write!(zenith_signal, "PREV LSN: none")?;
+        // Postgres doesn't recognize the zenith.signal file and doesn't need it.
+        if !self.full_backup {
+            // add zenith.signal file
+            let mut zenith_signal = String::new();
+            if self.prev_record_lsn == Lsn(0) {
+                if self.lsn == self.timeline.tline.get_ancestor_lsn() {
+                    write!(zenith_signal, "PREV LSN: none")?;
+                } else {
+                    write!(zenith_signal, "PREV LSN: invalid")?;
+                }
             } else {
-                write!(zenith_signal, "PREV LSN: invalid")?;
+                write!(zenith_signal, "PREV LSN: {}", self.prev_record_lsn)?;
             }
-        } else {
-            write!(zenith_signal, "PREV LSN: {}", self.prev_record_lsn)?;
+            self.ar.append(
+                &new_tar_header("zenith.signal", zenith_signal.len() as u64)?,
+                zenith_signal.as_bytes(),
+            )?;
         }
-        self.ar.append(
-            &new_tar_header("zenith.signal", zenith_signal.len() as u64)?,
-            zenith_signal.as_bytes(),
-        )?;
 
         //send pg_control
         let pg_control_bytes = pg_control.encode();

pageserver/src/page_service.rs

@@ -596,6 +596,7 @@ impl PageServerHandler {
         timelineid: ZTimelineId,
         lsn: Option<Lsn>,
         tenantid: ZTenantId,
+        full_backup: bool,
     ) -> anyhow::Result<()> {
         let span = info_span!("basebackup", timeline = %timelineid, tenant = %tenantid, lsn = field::Empty);
         let _enter = span.enter();
@@ -618,7 +619,7 @@ impl PageServerHandler {
         {
             let mut writer = CopyDataSink { pgb };
 
-            let basebackup = basebackup::Basebackup::new(&mut writer, &timeline, lsn)?;
+            let basebackup = basebackup::Basebackup::new(&mut writer, &timeline, lsn, full_backup)?;
             span.record("lsn", &basebackup.lsn.to_string().as_str());
             basebackup.send_tarball()?;
         }
@@ -721,7 +722,33 @@ impl postgres_backend::Handler for PageServerHandler {
             };
 
             // Check that the timeline exists
-            self.handle_basebackup_request(pgb, timelineid, lsn, tenantid)?;
+            self.handle_basebackup_request(pgb, timelineid, lsn, tenantid, false)?;
+            pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
+        }
+        // same as basebackup, but result includes relational data as well
+        else if query_string.starts_with("fullbackup ") {
+            let (_, params_raw) = query_string.split_at("fullbackup ".len());
+            let params = params_raw.split_whitespace().collect::<Vec<_>>();
+
+            ensure!(
+                params.len() == 3,
+                "invalid param number for fullbackup command"
+            );
+
+            let tenantid = ZTenantId::from_str(params[0])?;
+            let timelineid = ZTimelineId::from_str(params[1])?;
+
+            self.check_permission(Some(tenantid))?;
+
+            // Lsn is required for fullbackup, because otherwise we would not know
+            // at which lsn to upload this backup.
+            //
+            // The caller is responsible for providing a valid lsn
+            // and using it in the subsequent import.
+            let lsn = Some(Lsn::from_str(params[2])?);
+
+            // Check that the timeline exists
+            self.handle_basebackup_request(pgb, timelineid, lsn, tenantid, true)?;
             pgb.write_message_noflush(&BeMessage::CommandComplete(b"SELECT 1"))?;
         } else if query_string.to_ascii_lowercase().starts_with("set ") {
             // important because psycopg2 executes "SET datestyle TO 'ISO'"

pageserver/src/reltag.rs

@@ -3,7 +3,7 @@ use std::cmp::Ordering;
 use std::fmt;
 
 use postgres_ffi::relfile_utils::forknumber_to_name;
-use postgres_ffi::Oid;
+use postgres_ffi::{pg_constants, Oid};
 
 ///
 /// Relation data file segment id throughout the Postgres cluster.
@@ -75,6 +75,30 @@ impl fmt::Display for RelTag {
     }
 }
 
+impl RelTag {
+    pub fn to_segfile_name(&self, segno: u32) -> String {
+        let mut name = if self.spcnode == pg_constants::GLOBALTABLESPACE_OID {
+            "global/".to_string()
+        } else {
+            format!("base/{}/", self.dbnode)
+        };
+
+        name += &self.relnode.to_string();
+
+        if let Some(fork_name) = forknumber_to_name(self.forknum) {
+            name += "_";
+            name += fork_name;
+        }
+
+        if segno != 0 {
+            name += ".";
+            name += &segno.to_string();
+        }
+
+        name
+    }
+}
+
 ///
 /// Non-relation transaction status files (clog (a.k.a. pg_xact) and
 /// pg_multixact) in Postgres are handled by SLRU (Simple LRU) buffer,

test_runner/batch_others/test_fullbackup.py

@@ -0,0 +1,73 @@
+import subprocess
+from contextlib import closing
+
+import psycopg2.extras
+import pytest
+from fixtures.log_helper import log
+from fixtures.neon_fixtures import NeonEnvBuilder, PgBin, PortDistributor, VanillaPostgres
+from fixtures.neon_fixtures import pg_distrib_dir
+import os
+from fixtures.utils import mkdir_if_needed, subprocess_capture
+import shutil
+import getpass
+import pwd
+
+num_rows = 1000
+
+
+# Ensure that regular postgres can start from fullbackup
+def test_fullbackup(neon_env_builder: NeonEnvBuilder,
+                    pg_bin: PgBin,
+                    port_distributor: PortDistributor):
+
+    neon_env_builder.num_safekeepers = 1
+    env = neon_env_builder.init_start()
+
+    env.neon_cli.create_branch('test_fullbackup')
+    pgmain = env.postgres.create_start('test_fullbackup')
+    log.info("postgres is running on 'test_fullbackup' branch")
+
+    timeline = pgmain.safe_psql("SHOW neon.timeline_id")[0][0]
+
+    with closing(pgmain.connect()) as conn:
+        with conn.cursor() as cur:
+            # data loading may take a while, so increase statement timeout
+            cur.execute("SET statement_timeout='300s'")
+            cur.execute(f'''CREATE TABLE tbl AS SELECT 'long string to consume some space' || g
+                        from generate_series(1,{num_rows}) g''')
+            cur.execute("CHECKPOINT")
+
+            cur.execute('SELECT pg_current_wal_insert_lsn()')
+            lsn = cur.fetchone()[0]
+            log.info(f"start_backup_lsn = {lsn}")
+
+    # Set LD_LIBRARY_PATH in the env properly, otherwise we may use the wrong libpq.
+    # PgBin sets it automatically, but here we need to pipe psql output to the tar command.
+    psql_env = {'LD_LIBRARY_PATH': os.path.join(str(pg_distrib_dir), 'lib')}
+
+    # Get and unpack fullbackup from pageserver
+    restored_dir_path = os.path.join(env.repo_dir, "restored_datadir")
+    os.mkdir(restored_dir_path, 0o750)
+    query = f"fullbackup {env.initial_tenant.hex} {timeline} {lsn}"
+    cmd = ["psql", "--no-psqlrc", env.pageserver.connstr(), "-c", query]
+    result_basepath = pg_bin.run_capture(cmd, env=psql_env)
+    tar_output_file = result_basepath + ".stdout"
+    subprocess_capture(str(env.repo_dir), ["tar", "-xf", tar_output_file, "-C", restored_dir_path])
+
+    # HACK
+    # fullbackup returns neon specific pg_control and first WAL segment
+    # use resetwal to overwrite it
+    pg_resetwal_path = os.path.join(pg_bin.pg_bin_path, 'pg_resetwal')
+    cmd = [pg_resetwal_path, "-D", restored_dir_path]
+    pg_bin.run_capture(cmd, env=psql_env)
+
+    # Restore from the backup and find the data we inserted
+    port = port_distributor.get_port()
+    with VanillaPostgres(restored_dir_path, pg_bin, port, init=False) as vanilla_pg:
+        # TODO make port an optional argument
+        vanilla_pg.configure([
+            f"port={port}",
+        ])
+        vanilla_pg.start()
+        num_rows_found = vanilla_pg.safe_psql('select count(*) from tbl;', user="cloud_admin")[0][0]
+        assert num_rows == num_rows_found

test_runner/fixtures/neon_fixtures.py

@@ -1373,12 +1373,13 @@ def pg_bin(test_output_dir: str) -> PgBin:
 
 
 class VanillaPostgres(PgProtocol):
-    def __init__(self, pgdatadir: str, pg_bin: PgBin, port: int):
+    def __init__(self, pgdatadir: str, pg_bin: PgBin, port: int, init=True):
         super().__init__(host='localhost', port=port, dbname='postgres')
         self.pgdatadir = pgdatadir
         self.pg_bin = pg_bin
         self.running = False
-        self.pg_bin.run_capture(['initdb', '-D', pgdatadir])
+        if init:
+            self.pg_bin.run_capture(['initdb', '-D', pgdatadir])
         self.configure([f"port = {port}\n"])
 
     def configure(self, options: List[str]):