Crate persy

Persy - Transactional Persistence Engine

Simple single file durable, isolated, consistent, and atomic persistence engine based on copy on write. It guarantee the persistence of data even in case of crash through a in file write ahead log, and provide simple rust APIs for store simple bytes or value associated (index) data, provide also memory management logic to keep the file size in check.

Example

use persy::{Persy,Config};
//...
Persy::create("./target/data.persy")?;
let persy = Persy::open("./target/data.persy",Config::new())?;
let mut tx = persy.begin()?;
tx.create_segment("seg")?;
let data = vec![1;20];
tx.insert("seg", &data)?;
let prepared = tx.prepare()?;
prepared.commit()?;
for (_id,content) in persy.scan("seg")? {
    assert_eq!(content[0], 1);
    //....
}

Example Index

use persy::{Persy,Config, ValueMode};
//...
Persy::create("./target/index_data.persy")?;
let persy = Persy::open("./target/index_data.persy",Config::new())?;
let mut tx = persy.begin()?;
tx.create_index::<i32,i32>("index", ValueMode::Cluster)?;
tx.put("index", 10, 20)?;
let prepared = tx.prepare()?;
prepared.commit()?;
for (key,values) in persy.range::<i32,i32,_>("index", ..)? {
    assert_eq!(key, 10);
    assert_eq!(values.into_iter().collect::<Vec<_>>(), vec![20]);
    //....
}

Modules

• inspect

Structs

• ByteVec
  Wrapper for Vec<u8> for use it in index keys or values
• Config
  Persy configuration structure.
• IndexId
  Unique identifier of an index
• IndexInfo
  Index definition details
• IndexIter
  Index Iterator implementation for iterating on a range of keys
• OpenOptions
  Options, flags, configs which can be used to configure how a persy database is opened.
• Persy
  Main structure to operate persy storage files
• PersyId
  Identifier of a persistent record, can be used for read, update or delete the record
• Recover
  Intermediate recover status to select witch transactions to commit or rollback and list witch transactions are in a intermediate state
• SegmentId
  Represents a looked-up segment
• SegmentIter
  Iterator implementation used to scan a segment
• Snapshot
  Read snapshot at a specific point in time.
• SnapshotSegmentIter
  Iterator implementation to scan a segment at the current snapshot state.
• Transaction
  Transaction container, it include all the changes done in a transaction.
• TransactionConfig
  Configure the parameters for the transaction on the begin of a new transaction.
• TransactionFinalize
  prepared transaction state
• TxIndexIter
  Index Iterator implementation for iterating on a range of keys considering changes in transaction
• TxSegmentIter
  Iterator implementation to scan a segment considering in transaction changes.
• ValueIter
  Iterator of values relative to an index key use by get and range functions

Enums

• BeginTransactionError
• CreateError
• CreateIndexError
• CreateSegmentError
• DeleteError
• DropIndexError
• DropSegmentError
• GenericError
• IndexChangeError
• IndexError
• IndexOpsError
• IndexPutError
• IndexTypeId
  Enum of all the possible Key or Value types for indexes
• InsertError
• OpenError
• OpenMemoryError
• PE
  Wrapper enum for all the possible Persy errors,
• PersyError
  Enum of all possible errors from Persy
• PrepareError
• ReadError
• RecoverStatus
  Possible state of a transaction in the log
• SegmentError
• TxStrategy
  Concurrent Modification Strategy for resolution of conflict on commit.
• UpdateError
• ValueMode
  Define the behavior of the index in case a key value pair already exists

Traits

• IndexType
• ToIndexId
• ToSegmentId

Type Aliases

• TransactionId
  Custom identifier to track the transaction in the recover phase