com.google.gerrit.server.notedb

Class NotesMigration

java.lang.Object

com.google.gerrit.server.notedb.NotesMigration

Direct Known Subclasses:

MutableNotesMigration

public abstract class NotesMigration
extends java.lang.Object

Current low-level settings of the NoteDb migration for changes.

This class only describes the migration state of the Change entity group, since it is possible for a given site to be in different states of the Change NoteDb migration process while staying at the same ReviewDb schema version. It does not describe the migration state of non-Change tables; those are automatically migrated using the ReviewDb schema migration process, so the NoteDb migration state at a given ReviewDb schema cannot vary.

In many places, core Gerrit code should not directly care about the NoteDb migration state, and should prefer high-level APIs like ApprovalsUtil that don't require callers to inspect the migration state. The implementation of those utilities does care about the state, and should query the NotesMigration for the properties of the migration, for example, where new changes should be stored.

Core Gerrit code is mostly interested in one facet of the migration at a time (reading or writing, say), but not all combinations of return values are supported or even make sense.

This class controls the state of the migration according to options in gerrit.config. In general, any changes to these options should only be made by adventurous administrators, who know what they're doing, on non-production data, for the purposes of testing the NoteDb implementation. Changing options quite likely requires re-running MigrateToNoteDb. For these reasons, the options remain undocumented.

Note: Callers should not assume the values returned by NotesMigration's methods will not change in a running server.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	NotesMigration.Module

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	SECTION_NOTE_DB
protected java.util.concurrent.atomic.AtomicReference<com.google.gerrit.server.notedb.NotesMigration.Snapshot>	snapshot

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	NotesMigration(com.google.gerrit.server.notedb.NotesMigration.Snapshot snapshot)

Method Summary

Modifier and Type	Method and Description
NoteDbChangeState.PrimaryStorage	changePrimaryStorage()
boolean	commitChangeWrites()
boolean	disableChangeReviewDb() Disable ReviewDb access for changes.
boolean	equals(java.lang.Object o)
boolean	failChangeWrites()
boolean	failOnLoadForTest() Whether to fail when reading any data from NoteDb.
int	hashCode()
boolean	rawWriteChangesSetting() Write changes to NoteDb.
boolean	readChanges() Read changes from NoteDb.
boolean	readChangeSequence() Read sequential change ID numbers from NoteDb.
void	setConfigValues(org.eclipse.jgit.lib.Config cfg)

Methods inherited from class java.lang.Object

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

Field Detail

SECTION_NOTE_DB

public static final java.lang.String SECTION_NOTE_DB

See Also:

Constant Field Values

snapshot

protected final java.util.concurrent.atomic.AtomicReference<com.google.gerrit.server.notedb.NotesMigration.Snapshot> snapshot

Constructor Detail

NotesMigration

protected NotesMigration(com.google.gerrit.server.notedb.NotesMigration.Snapshot snapshot)

Method Detail

readChanges

public final boolean readChanges()

Read changes from NoteDb.

Change data is read from NoteDb refs, but ReviewDb is still the source of truth. If the loader determines NoteDb is out of date, the change data in NoteDb will be transparently rebuilt. This means that some code paths that look read-only may in fact attempt to write.

If true and writeChanges() = false, changes can still be read from NoteDb, but any attempts to write will generate an error.

rawWriteChangesSetting

public final boolean rawWriteChangesSetting()

Write changes to NoteDb.

This method is awkwardly named because you should be using either commitChangeWrites() or failChangeWrites() instead.

Updates to change data are written to NoteDb refs, but ReviewDb is still the source of truth. Change data will not be written unless the NoteDb refs are already up to date, and the write path will attempt to rebuild the change if not.

If false, the behavior when attempting to write depends on readChanges(). If readChanges() = false, writes to NoteDb are simply ignored; if true, any attempts to write will generate an error.

readChangeSequence

public final boolean readChangeSequence()

Read sequential change ID numbers from NoteDb.

If true, change IDs are read from refs/sequences/changes in All-Projects. If false, change IDs are read from ReviewDb's native sequences.

changePrimaryStorage

public final NoteDbChangeState.PrimaryStorage changePrimaryStorage()

Returns:

default primary storage for new changes.

disableChangeReviewDb

public final boolean disableChangeReviewDb()

Disable ReviewDb access for changes.

When set, ReviewDb operations involving the Changes table become no-ops. Lookups return no results; updates do nothing, as does opening, committing, or rolling back a transaction on the Changes table.

failOnLoadForTest

public boolean failOnLoadForTest()

Whether to fail when reading any data from NoteDb.

Used in conjunction with readChanges() for tests.

commitChangeWrites

public final boolean commitChangeWrites()

failChangeWrites

public final boolean failChangeWrites()

setConfigValues

public final void setConfigValues(org.eclipse.jgit.lib.Config cfg)

equals

public final boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public final int hashCode()

Overrides:

hashCode in class java.lang.Object