TransactionLog (Solr 6.6.0 API)

java.lang.Object
- org.apache.solr.update.TransactionLog

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

CdcrTransactionLog, HdfsTransactionLog
```
public class TransactionLog
extends Object
implements Closeable
```
Log Format: List{Operation, Version, ...} ADD, VERSION, DOC DELETE, VERSION, ID_BYTES DELETE_BY_QUERY, VERSION, String TODO: keep two files, one for [operation, version, id] and the other for the actual document data. That way we could throw away document log files more readily while retaining the smaller operation log files longer (and we can retrieve the stored fields from the latest documents from the index). This would require keeping all source fields stored of course. This would also allow to not log document data for requests with commit=true in them (since we know that if the request succeeds, all docs will be committed)

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`class`	`TransactionLog.FSReverseReader`
`class`	`TransactionLog.LogCodec`
`class`	`TransactionLog.LogReader`
`class`	`TransactionLog.ReverseReader`

Field Summary

Fields
Modifier and Type Field and Description

protected boolean deleteOnClose

static String END_MESSAGE

Fields
Modifier and Type	Field and Description
`protected boolean`	`deleteOnClose`
`static String`	`END_MESSAGE`

Constructor Summary

Constructors
Modifier Constructor and Description

protected TransactionLog()

Constructors
Modifier	Constructor and Description
`protected`	`TransactionLog()`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`protected void`	`addGlobalStrings(Collection<String> strings)`
`void`	`close()`
`void`	`closeOutput()` Move to a read-only state, closing and releasing resources while keeping the log available for reads
`void`	`decref()`
`protected void`	`endRecord(long startRecordPosition)`
`boolean`	`endsWithCommit()`
`void`	`finish(UpdateLog.SyncLevel syncLevel)`
`void`	`forceClose()`
`long`	`getLogSize()`
`TransactionLog.LogReader`	`getReader(long startingPos)` Returns a reader that can be used while a log is still in use.
`TransactionLog.ReverseReader`	`getReverseReader()` Returns a single threaded reverse reader
`void`	`incref()`
`Object`	`lookup(long pos)`
`int`	`numRecords()` Returns the number of records in the log (currently includes the header and an optional commit).
`long`	`position()` returns the current position in the log file
`void`	`rollback(long pos)`
`long`	`snapshot()` takes a snapshot of the current position and number of records for later possible rollback, and returns the position
`String`	`toString()`
`boolean`	`try_incref()`
`long`	`write(AddUpdateCommand cmd, int flags)` Writes an add update command to the transaction log.
`long`	`write(AddUpdateCommand cmd, long prevPointer, int flags)` Writes an add update command to the transaction log.
`long`	`writeCommit(CommitUpdateCommand cmd, int flags)`
`long`	`writeData(Object o)`
`long`	`writeDelete(DeleteUpdateCommand cmd, int flags)`
`long`	`writeDeleteByQuery(DeleteUpdateCommand cmd, int flags)`
`protected void`	`writeLogHeader(TransactionLog.LogCodec codec)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - END_MESSAGE
```
public static final String END_MESSAGE
```
    See Also:
    
    Constant Field Values
  - deleteOnClose
```
protected volatile boolean deleteOnClose
```
- Constructor Detail
  - TransactionLog
```
protected TransactionLog()
```
- Method Detail
  - numRecords
```
public int numRecords()
```
    Returns the number of records in the log (currently includes the header and an optional commit). Note: currently returns 0 for reopened existing log files.
  - endsWithCommit
```
public boolean endsWithCommit()
                       throws IOException
```
    Throws:
    
    IOException
  - snapshot
```
public long snapshot()
```
    takes a snapshot of the current position and number of records for later possible rollback, and returns the position
  - rollback
```
public void rollback(long pos)
              throws IOException
```
    Throws:
    
    IOException
  - writeData
```
public long writeData(Object o)
```
  - addGlobalStrings
```
protected void addGlobalStrings(Collection<String> strings)
```
  - writeLogHeader
```
protected void writeLogHeader(TransactionLog.LogCodec codec)
                       throws IOException
```
    Throws:
    
    IOException
  - endRecord
```
protected void endRecord(long startRecordPosition)
                  throws IOException
```
    Throws:
    
    IOException
  - write
```
public long write(AddUpdateCommand cmd,
                  int flags)
```
    Writes an add update command to the transaction log. This is not applicable for in-place updates; use write(AddUpdateCommand, long, int). (The previous pointer (applicable for in-place updates) is set to -1 while writing the command to the transaction log.)
    
    Parameters:
    
    cmd - The add update command to be written
    
    flags - Options for writing the command to the transaction log
    
    Returns:
    
    Returns the position pointer of the written update command
    
    See Also:
    
    write(AddUpdateCommand, long, int)
  - write
```
public long write(AddUpdateCommand cmd,
                  long prevPointer,
                  int flags)
```
    Writes an add update command to the transaction log. This should be called only for writing in-place updates, or else pass -1 as the prevPointer.
    
    Parameters:
    
    cmd - The add update command to be written
    
    prevPointer - The pointer in the transaction log which this update depends on (applicable for in-place updates)
    
    flags - Options for writing the command to the transaction log
    
    Returns:
    
    Returns the position pointer of the written update command
  - writeDelete
```
public long writeDelete(DeleteUpdateCommand cmd,
                        int flags)
```
  - writeDeleteByQuery
```
public long writeDeleteByQuery(DeleteUpdateCommand cmd,
                               int flags)
```
  - writeCommit
```
public long writeCommit(CommitUpdateCommand cmd,
                        int flags)
```
  - lookup
```
public Object lookup(long pos)
```
  - incref
```
public void incref()
```
  - try_incref
```
public boolean try_incref()
```
  - decref
```
public void decref()
```
  - position
```
public long position()
```
    returns the current position in the log file
  - closeOutput
```
public void closeOutput()
```
    Move to a read-only state, closing and releasing resources while keeping the log available for reads
  - finish
```
public void finish(UpdateLog.SyncLevel syncLevel)
```
  - close
```
public void close()
```
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
  - forceClose
```
public void forceClose()
```
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getLogSize
```
public long getLogSize()
```
  - getReader
```
public TransactionLog.LogReader getReader(long startingPos)
```
    Returns a reader that can be used while a log is still in use. Currently only *one* LogReader may be outstanding, and that log may only be used from a single thread.
  - getReverseReader
```
public TransactionLog.ReverseReader getReverseReader()
                                              throws IOException
```
    Returns a single threaded reverse reader
    
    Throws:
    
    IOException

Class TransactionLog

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

END_MESSAGE

deleteOnClose

Constructor Detail

TransactionLog

Method Detail

numRecords

endsWithCommit

snapshot

rollback

writeData

addGlobalStrings

writeLogHeader

endRecord

write

write

writeDelete

writeDeleteByQuery

writeCommit

lookup

incref

try_incref

decref

position

closeOutput

finish

close

forceClose

toString

getLogSize

getReader

getReverseReader