org.eclipse.jgit.internal.storage.reftable

Class ReftableCompactor

java.lang.Object

org.eclipse.jgit.internal.storage.reftable.ReftableCompactor

public class ReftableCompactor
extends Object

Merges reftables and compacts them into a single output.

For a partial compaction callers should setIncludeDeletes(boolean) to true to ensure the new reftable continues to use a delete marker to shadow any lower reftable that may have the reference present.

By default all log entries within the range defined by setMinUpdateIndex(long) and setMaxUpdateIndex(long) are copied, even if no references in the output file match the log records. Callers may truncate the log to a more recent time horizon with setOldestReflogTimeMillis(long), or disable the log altogether with setOldestReflogTimeMillis(Long.MAX_VALUE).

Constructor Summary

Constructors

Constructor and Description
ReftableCompactor()

Method Summary

Modifier and Type	Method and Description
void	addAll(List<? extends Reftable> readers) Add all of the tables, in the specified order.
void	compact(OutputStream out) Write a compaction to out.
ReftableWriter.Stats	getStats() Get statistics of the last written reftable.
ReftableCompactor	setCompactBytesLimit(long bytes) Set limit on number of bytes from source tables to compact.
ReftableCompactor	setConfig(ReftableConfig cfg) Set configuration for the reftable.
ReftableCompactor	setIncludeDeletes(boolean deletes) Whether to include deletions in the output, which may be necessary for partial compaction.
ReftableCompactor	setMaxUpdateIndex(long max) Set the maximum update index for log entries that appear in the compacted reftable.
ReftableCompactor	setMinUpdateIndex(long min) Set the minimum update index for log entries that appear in the compacted reftable.
ReftableCompactor	setOldestReflogTimeMillis(long timeMillis) Set oldest reflog time to preserve.
boolean	tryAddFirst(ReftableReader reader) Try to add this reader at the bottom of the stack.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReftableCompactor

public ReftableCompactor()

Method Detail

setConfig

public ReftableCompactor setConfig(ReftableConfig cfg)

Set configuration for the reftable.

Parameters:

cfg - configuration for the reftable.

Returns:

this

setCompactBytesLimit

public ReftableCompactor setCompactBytesLimit(long bytes)

Set limit on number of bytes from source tables to compact.

Parameters:

bytes - limit on number of bytes from source tables to compact.

Returns:

this

setIncludeDeletes

public ReftableCompactor setIncludeDeletes(boolean deletes)

Whether to include deletions in the output, which may be necessary for partial compaction.

Parameters:

deletes - true to include deletions in the output, which may be necessary for partial compaction.

Returns:

this

setMinUpdateIndex

public ReftableCompactor setMinUpdateIndex(long min)

Set the minimum update index for log entries that appear in the compacted reftable.

Parameters:

min - the minimum update index for log entries that appear in the compacted reftable. This should be 1 higher than the prior reftable's maxUpdateIndex if this table will be used in a stack.

Returns:

this

setMaxUpdateIndex

public ReftableCompactor setMaxUpdateIndex(long max)

Set the maximum update index for log entries that appear in the compacted reftable.

Parameters:

max - the maximum update index for log entries that appear in the compacted reftable. This should be at least 1 higher than the prior reftable's maxUpdateIndex if this table will be used in a stack.

Returns:

this

setOldestReflogTimeMillis

public ReftableCompactor setOldestReflogTimeMillis(long timeMillis)

Set oldest reflog time to preserve.

Parameters:

timeMillis - oldest log time to preserve. Entries whose timestamps are >= timeMillis will be copied into the output file. Log entries that predate timeMillis will be discarded. Specified in Java standard milliseconds since the epoch.

Returns:

this

addAll

public void addAll(List<? extends Reftable> readers)
            throws IOException

Add all of the tables, in the specified order.

Unconditionally adds all tables, ignoring the setCompactBytesLimit(long).

Parameters:

readers - tables to compact. Tables should be ordered oldest first/most recent last so that the more recent tables can shadow the older results. Caller is responsible for closing the readers.

Throws:

IOException - update indexes of a reader cannot be accessed.

tryAddFirst

public boolean tryAddFirst(ReftableReader reader)
                    throws IOException

Try to add this reader at the bottom of the stack.

A reader may be rejected by returning false if the compactor is already rewriting its setCompactBytesLimit(long). When this happens the caller should stop trying to add tables, and execute the compaction.

Parameters:

reader - the reader to insert at the bottom of the stack. Caller is responsible for closing the reader.

Returns:

true if the compactor accepted this table; false if the compactor has reached its limit.

Throws:

IOException - if size of reader, or its update indexes cannot be read.

compact

public void compact(OutputStream out)
             throws IOException

Write a compaction to out.

Parameters:

out - stream to write the compacted tables to. Caller is responsible for closing out.

Throws:

IOException - if tables cannot be read, or cannot be written.

getStats

public ReftableWriter.Stats getStats()

Get statistics of the last written reftable.

Returns:

statistics of the last written reftable.