Major changes and new concepts:
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.
Key
---
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.
See pgdatadir_mapping.rs for how relation blocks and metadata keys are
mapped to the Key struct.
Store arbitrary key-ranges in the layer files
---------------------------------------------
The concept of a "segment" is gone. Each layer file can store an arbitrary
range of Keys.
TODO:
- Deleting keys, to reclaim space. This isn't visible to Postgres, dropping
or truncating a relation works as you would expect if you look at it from
the compute node. If you drop a relation, for example, the relation is
removed from the metadata entry, so that it appears to be gone. However,
the layered repository implementation never reclaims the storage.
- Tracking "logical database size", for disk space quotas. That ought to
be reimplemented now in pgdatadir_mapping.rs, or perhaps in walingest.rs.
- LSM compaction. The logic for checkpointing and creating image layers is
very dumb. AFAIK the *read* code could deal with a full-fledged LSM tree
now consisting of the delta and image layers. But there's no code to
take a bunch of delta layers and compact them, and the heuristics for
when to create image layers is pretty dumb.
- The code to track the layers is inefficient. All layers are just stored in
a vector, and whenever we need to find a layer, we do a linear search in
it.
* 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/
