org.apache.hadoop.hive.common

Interface ValidTxnList

All Known Implementing Classes:

ValidReadTxnList

public interface ValidTxnList

Models the list of transactions that should be included in a snapshot. It is modelled as a high water mark, which is the largest transaction id that has been committed and a list of transactions that are not included.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	ValidTxnList.RangeResponse The response to a range query.

Field Summary

Fields

Modifier and Type	Field and Description
static String	VALID_TXNS_KEY Key used to store valid txn list in a Configuration object.

Method Summary

Methods

Modifier and Type	Method and Description
long	getHighWatermark() Get the largest committed transaction id.
long[]	getInvalidTransactions() Get the list of transactions under the high water mark that are not valid.
ValidTxnList.RangeResponse	isTxnRangeValid(long minTxnId, long maxTxnId) Find out if a range of transaction ids are valid.
boolean	isTxnValid(long txnid) Indicates whether a given transaction is valid.
void	readFromString(String src) Populate this validTxnList from the string.
String	writeToString() Write this validTxnList into a string.

Field Detail

VALID_TXNS_KEY

static final String VALID_TXNS_KEY

Key used to store valid txn list in a Configuration object.

See Also:

Constant Field Values

Method Detail

isTxnValid

boolean isTxnValid(long txnid)

Indicates whether a given transaction is valid. Note that valid may have different meanings for different implementations, as some will only want to see committed transactions and some both committed and aborted.

Parameters:

txnid - id for the transaction

Returns:

true if valid, false otherwise

isTxnRangeValid

ValidTxnList.RangeResponse isTxnRangeValid(long minTxnId,
                                         long maxTxnId)

Find out if a range of transaction ids are valid. Note that valid may have different meanings for different implementations, as some will only want to see committed transactions and some both committed and aborted.

Parameters:

minTxnId - minimum txnid to look for, inclusive

maxTxnId - maximum txnid to look for, inclusive

Returns:

Indicate whether none, some, or all of these transactions are valid.

writeToString

String writeToString()

Write this validTxnList into a string. This should produce a string that can be used by readFromString(String) to populate a validTxnsList.

readFromString

void readFromString(String src)

Populate this validTxnList from the string. It is assumed that the string was created via writeToString().

Parameters:

src - source string.

getHighWatermark

long getHighWatermark()

Get the largest committed transaction id.

Returns:

largest committed transaction id

getInvalidTransactions

long[] getInvalidTransactions()

Get the list of transactions under the high water mark that are not valid. Note that invalid may have different meanings for different implementations, as some will only want to see open transactions and some both open and aborted.

Returns:

a list of invalid transaction ids