Change 'zenith.signal' file to a human-readable format, similar to
backup_label. It can contain a "PREV LSN: %X/%X" line, or a special
value to indicate that it's OK to start with invalid LSN ('none'), or
that it's a read-only node and generating WAL is forbidden
('invalid').
The 'zenith pg create' and 'zenith pg start' commands now take a node
name parameter, separate from the branch name. If the node name is not
given, it defaults to the branch name, so this doesn't break existing
scripts.
If you pass "foo@<lsn>" as the branch name, a read-only node anchored
at that LSN is created. The anchoring is performed by setting the
'recovery_target_lsn' option in the postgresql.conf file, and putting
the server into standby mode with 'standby.signal'.
We no longer store the synthetic checkpoint record in the WAL segment.
The postgres startup code has been changed to use the copy of the
checkpoint record in the pg_control file, when starting in zenith
mode.
This adds a fast-path for the common case that the record doesn't
cross a page boundary. We now split off a new Bytes directly from the
original input buffer in that case, instead of copying the record to a
new BytesMut. Shaves about 5% of the page server's CPU time on my
laptop, in the 'test_bulk_insert' test.
Previously, the WAL receiver we would make a decoded copy of the current
Checkpoint before each WAL record, and compare it with the Checkpoint
after the record has been processed. If it has changed, the checkpoint
relish is updated in the repository. That's somewhat expensive, the
Checkpoint::encode() function is visible in 'perf' profile. Change that
so that we set a flag whenever the Checkpoint struct is modified, so that
we dont need to compare the whole struct anymore.
Otherwise restart of safekeeper before the first segment is filled makes it
report 0 as flushed LSN. To this end, tweak find_end_of_wal_segment to allow
starting from given LSN, not only from the start of the segment. While here,
make it less panicky.
In a passing fix two minor issues with basabackup:
* check that we can't create branches with pre-initdb LSN's
* normalize branch LSN's that are pointing to the segment boundary
patch by @knizhnik
closes#506
1) Extract consensus logic to safekeeper.rs.
2) Change the voting flow so that acceptor tells his epoch along with giving
the vote, not before it; otherwise it might get immediately stale. #294
3) Process messages from compute atomically and sync state properly. #270
4) Use separate structs for disk and network.
ref #315
Upgrade to bindgen 0.59, which has two new abilities:
- specify arbitrary #[derive] attributes to attach to generated structs
- request explicit padding fields
These two features are enough to replace transmute with serde/bincode.
Move ReceiveWalConn into its own file. Shuffle constants around so they
are close to the protocol they're associated with, or move them into
postgres_ffi if they seem to be global constants.
Replace XLogRecPtr with Lsn in wal_service.rs .
This removes the last use of XLogSegmentOffset and XLByteToSeg, so
delete them. (replaced by Lsn::segment_offset and Lsn::segment_number.)
