16e9740d8a
* Pre: Implement batch [a v] pair lookup.
* Pre: Add InternSet for sharing ref-counted handles to large values.
* Pre: Derive more for Entity.
* Pre: Return DB from creating; return TxReport from transact.
I explicitly am not supporting opening existing databases yet, let
alone upgrading databases from earlier versions. That can follow fast
once basic transactions are supported.
* Pre: Parse string temporary ID entities; remove ValueOrLookupRef.
This adds TempId entities, but we can't disambiguate String temporary
IDs from values without the use of the schema, so there's no new value
branch. Similarly, we can't disambiguate lookup-ref values from two
element list values without a schema, so we remove this entirely.
We'll handle the ambiguity later in the transactor.
* Persist partitions to SQL store; allocate transaction ID. (#186)
* Post: Test upserting with vectors.
This converts an existing test to EDN:
84a80f40f5/test/datomish/db_test.cljc (L193).
* Implement tempid upsert resolution algorithm. (#184)
* Post: Separate Tx out of DB.
This is very preliminary, since we don't have a real connection type
to manage transactions and their metadata yet.
* Post: Comment on implementation choices in the transactor.
* Review comment: Put long use lists on separate lines.
* Review comment: Accept String: Borrow<S> instead of just String.
* Review comment: Address nits.
92 lines
2.8 KiB
Rust
92 lines
2.8 KiB
Rust
// Copyright 2016 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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#![allow(dead_code)]
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use std::collections::HashMap;
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use std::collections::BTreeMap;
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extern crate mentat_core;
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pub use self::mentat_core::{
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Entid,
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ValueType,
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TypedValue,
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Attribute,
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AttributeBitFlags,
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Schema,
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};
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/// Represents one partition of the entid space.
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#[derive(Clone,Debug,Eq,Hash,Ord,PartialOrd,PartialEq)]
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pub struct Partition {
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/// The first entid in the partition.
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pub start: i64,
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/// The next entid to be allocated in the partition.
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pub index: i64,
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}
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impl Partition {
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pub fn new(start: i64, next: i64) -> Partition {
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assert!(start <= next, "A partition represents a monotonic increasing sequence of entids.");
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Partition { start: start, index: next }
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}
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}
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/// Map partition names to `Partition` instances.
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pub type PartitionMap = BTreeMap<String, Partition>;
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/// Represents the metadata required to query from, or apply transactions to, a Mentat store.
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///
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/// See https://github.com/mozilla/mentat/wiki/Thoughts:-modeling-db-conn-in-Rust.
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#[derive(Clone,Debug,Default,Eq,Hash,Ord,PartialOrd,PartialEq)]
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pub struct DB {
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/// Map partition name->`Partition`.
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///
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/// TODO: represent partitions as entids.
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pub partition_map: PartitionMap,
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/// The schema of the store.
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pub schema: Schema,
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}
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impl DB {
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pub fn new(partition_map: PartitionMap, schema: Schema) -> DB {
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DB {
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partition_map: partition_map,
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schema: schema
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}
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}
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}
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/// A pair [a v] in the store.
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///
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/// Used to represent lookup-refs and [TEMPID a v] upserts as they are resolved.
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pub type AVPair = (Entid, TypedValue);
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/// Map [a v] pairs to existing entids.
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///
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/// Used to resolve lookup-refs and upserts.
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pub type AVMap<'a> = HashMap<&'a AVPair, Entid>;
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/// A transaction report summarizes an applied transaction.
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// TODO: include map of resolved tempids.
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#[derive(Clone, Debug, Default, Eq, Hash, Ord, PartialOrd, PartialEq)]
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pub struct TxReport {
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/// The transaction ID of the transaction.
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pub tx_id: Entid,
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/// The timestamp when the transaction began to be committed.
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///
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/// This is milliseconds after the Unix epoch according to the transactor's local clock.
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// TODO: :db.type/instant.
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pub tx_instant: i64,
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}
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