The first COPY generates about 230 MB of write I/O, but the second
COPY, after deleting most of the rows and vacuuming the rows away,
generates 370 MB of writes. Both COPYs insert the same amount of data,
so they should generate roughly the same amount of I/O. This commit
doesn't try to fix the issue, just adds a test case to demonstrate it.
Add a new 'checkpoint' command to the pageserver API. Previously,
we've used 'do_gc' for that, but many tests, including this new one,
really only want to perform a checkpoint and don't care about GC. For
now, I only used the command in the new test, though, and didn't
convert any existing tests to use it.
If safekeepers sync fast enough, callmemaybe thread may never make a call before receiving Unsubscribe request. This leads to the situation, when pageserver lacks data that exists on safekeepers.
Change meaning of lsns in HOT_STANDBY_FEEDBACK:
flush_lsn = disk_consistent_lsn,
apply_lsn = remote_consistent_lsn
Update compute node backpressure configuration respectively.
Update compute node configuration:
set 'synchronous_commit=remote_write' in setup without safekeepers.
This way compute node doesn't have to wait for data checkpoint on pageserver.
This doesn't guarantee data durability, but we only use this setup for tests, so it's fine.
If a commit record contains XIDs that are stored on different CLOG pages,
we duplicate the commit record for each affected CLOG page. In the redo
routine, we must only apply the parts of the record that apply to the
CLOG page being restored. We got that right in the loop that handles the
sub-XIDs, but incorrectly always set the bit that corresponds to the main
XID.
The logic to compute the page number was broken, and as a result, only
the first page of multixact members was updated correctly. All the
rest were left as zeros. Improve test_multixact.py to generate more
multixacts, to cover this case.
Also fix the check that the restored PG data directory matches the
original one. Previously, the test compared the 'pg_new' cluster,
which is a bit silly because the test restored the 'pg_new' cluster
only a few lines earlier, so if the multixact WAL redo is somehow
broken, the comparison will just compare two broken data directories
and report success. Change it to compare the original datadir, the one
where the multixacts were originally created, with a restored image of
the same.
This is needed for implementation of tenant rebalancing. With this
change safekeeper becomes aware of which pageserver is supposed to be
used for replication from this particular compute.
This patch introduces fixes for several problems affecting
LLVM-based code coverage:
* Daemonizing parent processes should call _exit() to prevent
coverage data file corruption (*.profraw) due to concurrent writes.
* Implement proper shutdown handlers in safekeeper.
Persist full history of term switches on safekeepers instead of storing only the
single term of the highest entry (called epoch). This allows easily and
correctly find the divergence point of two logs and truncate the obsolete part
before overwriting it with entries of the newer proposer(s).
Full history of the proposer is transferred in separate message before proposer
starts streaming; it is immediately persisted by safekeeper, though he might not
yet have entries for some older terms there. That's because we can't atomically
append to WAL and update the control file anyway, so locally available WAL must
be taken into account when looking at the history.
We should sometimes purge term history entries beyond truncate_lsn; this is not
done here.
Per https://github.com/zenithdb/rfcs/pull/12Closes#296.
Bumps vendor/postgres.
Out of scope LSNs include pre initdb LSNs, and LSNs prior to
latest_gc_cutoff.
To get there there was also two cleanups:
* Fix error handling in Execute message handler. This fixes behaviour
when basebackup retured an error. Previously pageserver thread just
died.
* Remove "ancestor" file which previously contained ancestor id and
branch lsn. Currently the same data can be obtained from metadata file.
And just the way we handled ancestor file in the code introduced the
case when branching fails timeline directory is created but there is no data in it
except ancestor file. And this confused gc because it scans
directories. So it is better to just remove ancestor file and clean up
this timeline directory creation so it happens after all validity
checks have passed
This introduces new timeline field latest_gc_cutoff. It is updated
before each gc iteration. New check is added to branch_timelines to
prevent branch creation with start point less than latest_gc_cutoff.
Also this adds a check to get_page_at_lsn which asserts that lsn at
which the page is requested was not garbage collected. This check
currently is triggered for readonly nodes which are pinned to specific
lsn and because they are not tracked in pageserver garbage collection
can remove data that still might be referenced. This is a bug and will
be fixed separately.
During parallel load of a table, Postgres sometimes requests a page from
the page server for which no WAL has been generated yet. That's normal;
Postgres expects the page to be full of zeros. There was a special case
for that in LayeredTimeline::materialize_page, but the problem remained
when you're crossing a segment boundary, so that there's no layer for
the segment at all.
It would be nice to have a more robust cross-check for this case. That
might need help from the Postgres side. But this extends the bandaid fix
we had in materialize_page() to the case where cross segment boundary.
Fixes https://github.com/zenithdb/zenith/issues/841
* change zenith-perf-data checkout ref to be main
* set cluster id through secrets so there is no code changes required
when we wipe out clusters on staging
* display full pgbench output on error
tests are based on self-hosted runner which is physically close
to our staging deployment in aws, currently tests consist of
various configurations of pgbenchi runs.
Also these changes rework benchmark fixture by removing globals and
allowing to collect reports with desired metrics and dump them to json
for further analysis. This is also applicable to usual performance tests
which use local zenith binaries.
This calculation is not that heavy but it is needed only in tests, and
in case the number of tenants/timelines is high the calculation can take
noticeable time.
Resolves https://github.com/zenithdb/zenith/issues/804
The 'zenith' CLI utility can now be used to launch safekeepers. By
default, one safekeeper is configured. There are new 'safekeeper
start/stop' subcommands to manage the safekeepers. Each safekeeper is
given a name that can be used to identify the safekeeper to start/stop
with the 'zenith start/stop' commands. The safekeeper data is stored
in '.zenith/safekeepers/<name>'.
The 'zenith start' command now starts the pageserver and also all
safekeepers. 'zenith stop' stops pageserver, all safekeepers, and all
postgres nodes.
Introduce new 'zenith pageserver start/stop' subcommands for
starting/stopping just the page server.
The biggest change here is to the 'zenith init' command. This adds a
new 'zenith init --config=<path to toml file>' option. It takes a toml
config file that describes the environment. In the config file, you
can specify options for the pageserver, like the pg and http ports,
and authentication. For each safekeeper, you can define a name and the
pg and http ports. If you don't use the --config option, you get a
default configuration with a pageserver and one safekeeper. Note that
that's different from the previous default of no safekeepers. Any
fields that are omitted in the configuration file are filled with
defaults. You can also specify the initial tenant ID in the config
file. A couple of sample config files are added in the control_plane/
directory.
The --pageserver-pg-port, --pageserver-http-port, and
--pageserver-auth options to 'zenith init' are removed. Use a config
file instead.
Finally, change the python test fixtures to use the new 'zenith'
commands and the config file to describe the environment.
We've seen some failures with "Address already in use" errors in the
tests. It's not clear why, perhaps some server processes are not cleaned
up properly after test, or maybe the socket is still in TIME_WAIT state.
In any case, let's make the tests more robust by checking that the port
is free, before trying to use it.
Instead of having a lot of separate fixtures for setting up the page
server, the compute nodes, the safekeepers etc., have one big ZenithEnv
object that encapsulates the whole environment. Every test either uses
a shared "zenith_simple_env" fixture, which contains the default setup
of a pageserver with no authentication, and no safekeepers. Tests that
want to use safekeepers or authentication set up a custom test-specific
ZenithEnv fixture.
Gathering information about the whole environment into one object makes
some things simpler. For example, when a new compute node is created,
you no longer need to pass the 'wal_acceptors' connection string as
argument to the 'postgres.create_start' function. The 'create_start'
function fetches that information directly from the ZenithEnv object.
Each test now gets its own test output directory, like
'test_output/test_foobar', even when TEST_SHARED_FIXTURES is used.
When TEST_SHARED_FIXTURES is not used, the zenith repo for each test
is created under a 'repo' subdir inside the test output dir, e.g.
'test_output/test_foobar/repo'
* We actually need Python 3.7 because of dataclasses
* Rerun 'pipenv lock' under Python 3.7 and add 'pipenv' to dev deps
* Update docs on developing for Python 3.7
* CircleCI: use Python 3.7 via Docker image instead of Orb
* Fix bugs found by mypy
* Add some missing types and runtime checks, remove unused code
* Make ZenithPageserver start right away for better type safety
* Add `types-*` packages to Pipfile
* Pin mypy version and run it on CircleCI
* Add yapf run to CircleCI
* Pin yapf version
* Enable `SPLIT_ALL_TOP_LEVEL_COMMA_SEPARATED_VALUES` setting
* Reformat all existing code with slight manual adjustments
* test_runner/README: note that yapf is forced
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 is in preparation for supporting read-only nodes. You can launch
multiple read-only nodes on the same brach, so we need an identifier
for each node, separate from the branch name.
Which is mainly generational state (terms) and useful LSNs.
Also add /status basic healthcheck request which is now used in tests to
determine the safekeeper is up; this fixes#726.
ref #115
* Use logging in python tests
* Use f-strings for logs
* Don't log test output while running
* Use only pytest logging handler
* Add more info about pytest logging
