This is a backwards-incompatible change. The new pageserver cannot
read repositories created with an old pageserver binary, or vice
versa.
Simplify Repository to a value-store
------------------------------------
Move the responsibility of tracking relation metadata, like which
relations exist and what are their sizes, from Repository to a new
module, pgdatadir_mapping.rs. The interface to Repository is now a
simple key-value PUT/GET operations.
It's still not any old key-value store though. A Repository is still
responsible from handling branching, and every GET operation comes
with an LSN.
Mapping from Postgres data directory to keys/values
---------------------------------------------------
All the data is now stored in the key-value store. The
'pgdatadir_mapping.rs' module handles mapping from PostgreSQL objects
like relation pages and SLRUs, to key-value pairs.
The key to the Repository key-value store is a Key struct, which
consists of a few integer fields. It's wide enough to store a full
RelFileNode, fork and block number, and to distinguish those from
metadata keys.
'pgdatadir_mapping.rs' is also responsible for maintaining a
"partitioning" of the keyspace. Partitioning means splitting the
keyspace so that each partition holds a roughly equal number of keys.
The partitioning is used when new image layer files are created, so
that each image layer file is roughly the same size.
The partitioning is also responsible for reclaiming space used by
deleted keys. The Repository implementation doesn't have any explicit
support for deleting keys. Instead, the deleted keys are simply
omitted from the partitioning, and when a new image layer is created,
the omitted keys are not copied over to the new image layer. We might
want to implement tombstone keys in the future, to reclaim space
faster, but this will work for now.
Changes to low-level layer file code
------------------------------------
The concept of a "segment" is gone. Each layer file can now store an
arbitrary range of Keys.
Checkpointing, compaction
-------------------------
The background tasks are somewhat different now. Whenever
checkpoint_distance is reached, the WAL receiver thread "freezes" the
current in-memory layer, and creates a new one. This is a quick
operation and doesn't perform any I/O yet. It then launches a
background "layer flushing thread" to write the frozen layer to disk,
as a new L0 delta layer. This mechanism takes care of durability. It
replaces the checkpointing thread.
Compaction is a new background operation that takes a bunch of L0
delta layers, and reshuffles the data in them. It runs in a separate
compaction thread.
Deployment
----------
This also contains changes to the ansible scripts that enable having
multiple different pageservers running at the same time in the staging
environment. We will use that to keep an old version of the pageserver
running, for clusters created with the old version, at the same time
with a new pageserver with the new binary.
Author: Heikki Linnakangas
Author: Konstantin Knizhnik <knizhnik@zenith.tech>
Author: Andrey Taranik <andrey@zenith.tech>
Reviewed-by: Matthias Van De Meent <matthias@zenith.tech>
Reviewed-by: Bojan Serafimov <bojan@zenith.tech>
Reviewed-by: Konstantin Knizhnik <knizhnik@zenith.tech>
Reviewed-by: Anton Shyrabokau <antons@zenith.tech>
Reviewed-by: Dhammika Pathirana <dham@zenith.tech>
Reviewed-by: Kirill Bulatov <kirill@zenith.tech>
Reviewed-by: Anastasia Lubennikova <anastasia@zenith.tech>
Reviewed-by: Alexey Kondratov <alexey@zenith.tech>
More rows, and test with serial and parallel plans. But fewer iterations,
so that the tests run in < 1 minutes, and we don't need to mark them as
"slow".
* Add --id argument to safekeeper setting its unique u64 id.
In preparation for storage node messaging. IDs are supposed to be monotonically
assigned by the console. In tests it is issued by ZenithEnv; at the zenith cli
level and fixtures, string name is completely replaced by integer id. Example
TOML configs are adjusted accordingly.
Sequential ids are chosen over Zid mainly because they are compact and easy to
type/remember.
* add node id to pageserver
This adds node id parameter to pageserver configuration. Also I use a
simple builder to construct pageserver config struct to avoid setting
node id to some temporary invalid value. Some of the changes in test
fixtures are needed to split init and start operations for envrionment.
Co-authored-by: Arseny Sher <sher-ars@yandex.ru>
Use GUC zenith.max_cluster_size to set the limit.
If limit is reached, extend requests will throw out-of-space error.
When current size is too close to the limit - throw a warning.
Add new test: test_timeline_size_quota.
* Fix checkpoint.nextXid update
* Add test for cehckpoint.nextXid
* Fix indentation of test_next_xid.py
* Fix mypy error in test_next_xid.py
* Tidy up the test case.
* Add a unit test
Co-authored-by: Heikki Linnakangas <heikki@zenith.tech>
Now zenith_cli handles wal_acceptors config internally, and if we
will append wal_acceptors to postgresql.conf in python tests, then
it will contain duplicate wal_acceptors config.
* Reproduce github issue #1047.
* Use RwLock to protect gc_cuttof_lsn
* Eeduce number of updates in test_gc_aggressive
* Change test_prohibit_get_page_at_lsn_for_garbage_collected_pages test
* Change test_prohibit_get_page_at_lsn_for_garbage_collected_pages
* Lock latest_gc_cutoff_lsn in all operations accessing storage to prevent race conditions with GC
* Remove random sleep between wait_for_lsn and get_page_at_lsn
* Initialize latest_gc_cutoff with initdb_lsn and remove separate check that lsn >= initdb_lsn
* Update test_prohibit_branch_creation_on_pre_initdb_lsn test
Co-authored-by: Heikki Linnakangas <heikki@zenith.tech>
This patch includes attach/detach http endpoints in pageservers. Some
changes in callmemaybe handling inside safekeeper and an integrational
test to check migration with and without load. There are still some
rough edges that will be addressed in follow up patches
Mainly because it has better support for installing the packages from
different python versions.
It also has better dependency resolver than Pipenv. And supports modern
standard for python dependency management. This includes usage of
pyproject.toml for project specific configuration instead of per
tool conf files. See following links for details:
https://pip.pypa.io/en/stable/reference/build-system/pyproject-toml/https://www.python.org/dev/peps/pep-0518/
