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refine 1->3 upgrade process

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In hindsight, the "post_tx" step in the upgrade process introduced in
e7f5733 doesn't make sense. If the procedure fails at this stage, nothing says
it still needs to be completed. If the sample file dirs have to be updated
after the database, then there should be another database version to mark that
it's fully completed, and indeed that's the purpose version 3 serves. So get
rid of the Upgrader trait and just go back to a simple run function per
version.

In the case of the sample file dir metadata, it actually can happen before the
database transaction; the stuff written to the database later just needs to be
consistent with what it finds if there's an existing metadata file from a
half-completed update.

For safety, ensure there are no unexpected directory contents before
upgrading 1->2, and ensure the metadata matches before upgrading 2->3.
This commit is contained in:
Scott Lamb
2018-03-01 09:26:03 -08:00
parent bcf42fe02c
commit f01f523c2c
6 changed files with 449 additions and 417 deletions
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136
db/upgrade/v2_to_v3.rs
View File

@@ -29,20 +29,95 @@
// along with this program. If not, see <http://www.gnu.org/licenses/>.
/// Upgrades a version 2 schema to a version 3 schema.
/// Note that a version 2 schema is never actually used; so we know the upgrade from version 1 was
/// completed, and possibly an upgrade from 2 to 3 is half-finished.
use db::{self, FromSqlUuid};
use dir;
use failure::Error;
use libc;
use schema;
use std::io::{self, Write};
use std::mem;
use std::sync::Arc;
use rusqlite;
use uuid::Uuid;
pub struct U;
/// Opens the sample file dir.
///
/// Makes a couple simplifying assumptions valid for version 2:
/// * there's only one dir.
/// * it has a last completed open.
fn open_sample_file_dir(tx: &rusqlite::Transaction) -> Result<Arc<dir::SampleFileDir>, Error> {
let (p, s_uuid, o_id, o_uuid, db_uuid): (String, FromSqlUuid, i32, FromSqlUuid, FromSqlUuid) =
tx.query_row(r#"
select
s.path, s.uuid, s.last_complete_open_id, o.uuid, m.uuid
from
sample_file_dir s
join open o on (s.last_complete_open_id = o.id)
cross join meta m
"#, &[], |row| {
(row.get_checked(0).unwrap(),
row.get_checked(1).unwrap(),
row.get_checked(2).unwrap(),
row.get_checked(3).unwrap(),
row.get_checked(4).unwrap())
})?;
let mut meta = schema::DirMeta::default();
meta.db_uuid.extend_from_slice(&db_uuid.0.as_bytes()[..]);
meta.dir_uuid.extend_from_slice(&s_uuid.0.as_bytes()[..]);
{
let open = meta.mut_last_complete_open();
open.id = o_id as u32;
open.uuid.extend_from_slice(&o_uuid.0.as_bytes()[..]);
}
dir::SampleFileDir::open(&p, &meta)
}
pub fn new<'a>(_args: &'a super::Args) -> Result<Box<super::Upgrader + 'a>, Error> {
Ok(Box::new(U))
pub fn run(_args: &super::Args, tx: &rusqlite::Transaction) -> Result<(), Error> {
let d = open_sample_file_dir(&tx)?;
let mut stmt = tx.prepare(r#"
select
composite_id,
sample_file_uuid
from
recording_playback
"#)?;
let mut rows = stmt.query(&[])?;
while let Some(row) = rows.next() {
let row = row?;
let id = db::CompositeId(row.get_checked(0)?);
let sample_file_uuid: FromSqlUuid = row.get_checked(1)?;
let from_path = get_uuid_pathname(sample_file_uuid.0);
let to_path = get_id_pathname(id);
let r = unsafe { dir::renameat(&d.fd, from_path.as_ptr(), &d.fd, to_path.as_ptr()) };
if let Err(e) = r {
if e.kind() == io::ErrorKind::NotFound {
continue; // assume it was already moved.
}
Err(e)?;
}
}
// These create statements match the schema.sql when version 3 was the latest.
tx.execute_batch(r#"
alter table recording_playback rename to old_recording_playback;
create table recording_playback (
composite_id integer primary key references recording (composite_id),
sample_file_sha1 blob not null check (length(sample_file_sha1) = 20),
video_index blob not null check (length(video_index) > 0)
);
insert into recording_playback
select
composite_id,
sample_file_sha1,
video_index
from
old_recording_playback;
drop table old_recording_playback;
"#)?;
Ok(())
}
/// Gets a pathname for a sample file suitable for passing to open or unlink.
@@ -59,58 +134,3 @@ fn get_id_pathname(id: db::CompositeId) -> [libc::c_char; 17] {
write!(&mut buf[..16], "{:016x}", id.0).expect("can't format id to pathname buf");
unsafe { mem::transmute::<[u8; 17], [libc::c_char; 17]>(buf) }
}
impl super::Upgrader for U {
fn in_tx(&mut self, tx: &rusqlite::Transaction) -> Result<(), Error> {
let path: String = tx.query_row(r#"
select path from sample_file_dir
"#, &[], |row| { row.get_checked(0) })??;
// Build map of stream -> dirname.
let d = dir::Fd::open(None, &path, false)?;
//let stream_to_dir = build_stream_to_dir(&d, tx)?;
let mut stmt = tx.prepare(r#"
select
composite_id,
sample_file_uuid
from
recording_playback
"#)?;
let mut rows = stmt.query(&[])?;
while let Some(row) = rows.next() {
let row = row?;
let id = db::CompositeId(row.get_checked(0)?);
let sample_file_uuid: FromSqlUuid = row.get_checked(1)?;
let from_path = get_uuid_pathname(sample_file_uuid.0);
let to_path = get_id_pathname(id);
//let to_dir: &dir::Fd = stream_to_dir[stream_id as usize].as_ref().unwrap();
let r = unsafe { dir::renameat(&d, from_path.as_ptr(), &d, to_path.as_ptr()) };
if let Err(e) = r {
if e.kind() == io::ErrorKind::NotFound {
continue; // assume it was already moved.
}
Err(e)?;
}
}
// These create statements match the schema.sql when version 3 was the latest.
tx.execute_batch(r#"
alter table recording_playback rename to old_recording_playback;
create table recording_playback (
composite_id integer primary key references recording (composite_id),
sample_file_sha1 blob not null check (length(sample_file_sha1) = 20),
video_index blob not null check (length(video_index) > 0)
);
insert into recording_playback
select
composite_id,
sample_file_sha1,
video_index
from
old_recording_playback;
drop table old_recording_playback;
"#)?;
Ok(())
}
}