Documentation
¶
Overview ¶
Package postgres is the PostgreSQL engine of blobfs:
- Engine builds the PostgreSQL variant of the data package's variation points over native-tier statements.
- Migrations returns blobfs's schema as a migration set, named Source and recorded in the history table Table.
- TreeLockKey is the tree lock's advisory lock key, derived from TreeLockName.
A consumer selects the engine by importing the package and installing Engine, with no registry, init, or flag:
store, err := data.New(catalog, dialect, data.WithEngine(postgres.Engine))
The variant embeds the baseline it is given and overrides all three variation points: the tree lock is pg_advisory_xact_lock over TreeLockKey, path resolution is one recursive statement over a text[] parameter, and the file hold is SELECT ... FOR NO KEY UPDATE, which writes no row version. Each statement file declares the native tier and carries a port note. The package imports only the data package, the root package, and sqlate, and names no driver.
A released migration file never changes in text or name; the golden-hash test in this package pins each one. See "postgres: the PostgreSQL engine" and "The schema" in docs/features.md.
Index ¶
Constants ¶
const ( // Source is the migration set's name and the prefix of every object // the set owns. Source = "blobfs" // Table is the history table the set's migrations are recorded in. It // is distinct from a consumer's own history table, so the two sets keep // separate version lines. Table = "blobfs_schema_version" )
const TreeLockKey int64 = -8521165719926625175
TreeLockKey is the tree lock's advisory lock key: the 64-bit FNV-1a hash of TreeLockName read as a signed integer. A consumer that takes advisory locks of its own avoids it.
const TreeLockName = "blobfs_directory.tree"
TreeLockName is the name the tree lock's key is derived from: the blobfs_ namespace and the table whose shape the lock serializes.
Variables ¶
This section is empty.
Functions ¶
func Engine ¶
func Engine(catalog *query.Catalog, dialect sqlate.Dialect, base data.Variant) (data.Variant, error)
Engine is the PostgreSQL engine for data.WithEngine: it compiles the variant's three statements against catalog for dialect, with no I/O, and returns the PostgreSQL variant over base. The catalog must carry the blobfs namespace, since resolve_path includes the published directory columns.
func Migrations ¶
Migrations returns blobfs's migration set for PostgreSQL, named Source, recorded in Table, and read from the embedded migrations directory. A consumer declares it below its own set in migrate.New.
Types ¶
This section is empty.
Source Files