Package dev.frostlake.persistence

Class PersistenceManager

java.lang.Object

dev.frostlake.persistence.PersistenceManager

public class PersistenceManager
extends Object

Manages persistence of catalog metadata and table data to disk

Constructor Summary

Constructors

Constructor	Description
PersistenceManager(EngineConfig config)

Method Summary

Modifier and Type	Method	Description
void	applyState(CatalogSnapshot snapshot, MemoryTableDataStore tableData, Catalog catalog, StorageEngine storageEngine)	Apply an in-memory engine state (from buildState(dev.frostlake.metastore.Catalog, dev.frostlake.storage.StorageEngine, dev.frostlake.persistence.MemoryTableDataStore)) into a fresh catalog + storage.
CatalogSnapshot	buildState(Catalog catalog, StorageEngine storageEngine, MemoryTableDataStore tableData)	Build the full engine state entirely in memory — the write half of an in-JVM engine clone.
void	checkpointTo(Path dir, Catalog catalog, StorageEngine storageEngine)	Write a full state snapshot (catalog + table data) into dir, regardless of the persistence.enabled flag — the durable side of a WAL checkpoint.
void	clearAll()	Clear all persisted data
void	initialize()	Initialize persistence directory structure
void	loadCatalog(Catalog catalog, StorageEngine storageEngine)	Load catalog metadata from disk
void	noteStatementExecuted()	Note that a statement ran (or was attempted — a failed one can still leave a persistent change, e.g. an advanced sequence), so the next autosave interval must write.
void	restoreFrom(Path dir, Catalog catalog, StorageEngine storageEngine)	Restore a full state snapshot previously written by checkpointTo(java.nio.file.Path, dev.frostlake.metastore.Catalog, dev.frostlake.storage.StorageEngine) into the live catalog + storage, regardless of the persistence.enabled flag — used during WAL recovery.
void	saveCatalog(Catalog catalog, StorageEngine storageEngine)	Save catalog metadata to disk
void	startAutoSave(Catalog catalog, StorageEngine storageEngine)	Start auto-save scheduler if enabled
void	stopAutoSave()	Stop auto-save scheduler

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

PersistenceManager

public PersistenceManager(EngineConfig config)

Method Details

noteStatementExecuted

public void noteStatementExecuted()

Note that a statement ran (or was attempted — a failed one can still leave a persistent change, e.g. an advanced sequence), so the next autosave interval must write.

initialize

public void initialize()
                throws IOException

Initialize persistence directory structure

Throws:

IOException

startAutoSave

public void startAutoSave(Catalog catalog,
 StorageEngine storageEngine)

Start auto-save scheduler if enabled

stopAutoSave

public void stopAutoSave()

Stop auto-save scheduler

checkpointTo

public void checkpointTo(Path dir,
 Catalog catalog,
 StorageEngine storageEngine)
                  throws IOException

Write a full state snapshot (catalog + table data) into dir, regardless of the persistence.enabled flag — the durable side of a WAL checkpoint. The WAL records this snapshot's reference only after this returns, so a crash here just leaves an ignored orphan directory.

Throws:

IOException

buildState

public CatalogSnapshot buildState(Catalog catalog,
 StorageEngine storageEngine,
 MemoryTableDataStore tableData)
                           throws IOException

Build the full engine state entirely in memory — the write half of an in-JVM engine clone. The catalog snapshot is returned; every table's rows land in tableData.

Throws:

IOException

applyState

public void applyState(CatalogSnapshot snapshot,
 MemoryTableDataStore tableData,
 Catalog catalog,
 StorageEngine storageEngine)
                throws IOException,
ClassNotFoundException

Apply an in-memory engine state (from buildState(dev.frostlake.metastore.Catalog, dev.frostlake.storage.StorageEngine, dev.frostlake.persistence.MemoryTableDataStore)) into a fresh catalog + storage.

Throws:

IOException

ClassNotFoundException

restoreFrom

public void restoreFrom(Path dir,
 Catalog catalog,
 StorageEngine storageEngine)
                 throws IOException,
ClassNotFoundException

Restore a full state snapshot previously written by checkpointTo(java.nio.file.Path, dev.frostlake.metastore.Catalog, dev.frostlake.storage.StorageEngine) into the live catalog + storage, regardless of the persistence.enabled flag — used during WAL recovery.

Throws:

IOException

ClassNotFoundException

saveCatalog

public void saveCatalog(Catalog catalog,
 StorageEngine storageEngine)
                 throws IOException

Save catalog metadata to disk

Throws:

IOException

loadCatalog

public void loadCatalog(Catalog catalog,
 StorageEngine storageEngine)
                 throws IOException,
ClassNotFoundException

Load catalog metadata from disk

Throws:

IOException

ClassNotFoundException

clearAll

public void clearAll()
              throws IOException

Clear all persisted data

Throws:

IOException