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zeekay
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This is our fork, so it should read like it. `import datastore_orm` instead of `from infi.clickhouse_orm import ...`: `infi` was the original vendor's org namespace, and carrying someone else's org name through every import in the consuming codebase is not a fork, it is a vendored copy that never got renamed. The `infi` namespace package is gone entirely (src/infi/__init__.py with it), the distribution is `datastore-orm`, and the metadata points at Hanzo rather than at the upstream repo and author. NOT renamed, deliberately: the migration history tables are still `infi_clickhouse_orm_migrations`. That name is persisted state — 448 rows in production key off it — so changing it is a data migration, not a rename. Doing it carelessly reproduces the exact failure this fork just hit, where a package rename orphaned the history and silently blocked every migration.
2.7 KiB
2.7 KiB
System Models
System models are read only models for implementing part of the system's functionality, and for providing access to information about how the system is working.
Currently the following system models are supported:
| Class | DB Table | Comments |
|---|---|---|
| SystemPart | system.parts | Gives methods to work with partitions. See below. |
Partitions and Parts
A partition in a table is data for a single calendar month. Table "system.parts" contains information about each part.
| Method | Parameters | Comments |
|---|---|---|
| get(static) | database, conditions="" | Gets database partitions, filtered by conditions |
| get_active(static) | database, conditions="" | Gets only active (not detached or dropped) partitions, filtered by conditions |
| detach | settings=None | Detaches the partition. Settings is a dict of params to pass to http request |
| drop | settings=None | Drops the partition. Settings is a dict of params to pass to http request |
| attach | settings=None | Attaches already detached partition. Settings is a dict of params to pass to http request |
| freeze | settings=None | Freezes (makes backup) of the partition. Settings is a dict of params to pass to http request |
| fetch | settings=None | Fetches partition. Settings is a dict of params to pass to http request |
Usage example:
from datastore_orm import Database, SystemPart
db = Database('my_test_db', db_url='http://192.168.1.1:8050', username='scott', password='tiger')
partitions = SystemPart.get_active(db, conditions='') # Getting all active partitions of the database
if len(partitions) > 0:
partitions = sorted(partitions, key=lambda obj: obj.name) # Partition name is YYYYMM, so we can sort so
partitions[0].freeze() # Make a backup in /opt/clickhouse/shadow directory
partitions[0].drop() # Dropped partition
Note: system.parts stores information for all databases. To be correct, SystemPart model was designed to receive only parts belonging to the given database instance.