/**
* This will look through the completed_txn_components table and look for partitions or tables
* that may be ready for compaction. Also, look through txns and txn_components tables for aborted
* transactions that we should add to the list.
*
* @param maxAborted Maximum number of aborted queries to allow before marking this as a potential
* compaction.
* @return list of CompactionInfo structs. These will not have id, type, or runAs set since these
* are only potential compactions not actual ones.
*/
public Set<CompactionInfo> findPotentialCompactions(int maxAborted) throws MetaException {
Connection dbConn = getDbConn();
Set<CompactionInfo> response = new HashSet<CompactionInfo>();
try {
Statement stmt = dbConn.createStatement();
// Check for completed transactions
String s =
"select distinct ctc_database, ctc_table, "
+ "ctc_partition from COMPLETED_TXN_COMPONENTS";
LOG.debug("Going to execute query <" + s + ">");
ResultSet rs = stmt.executeQuery(s);
while (rs.next()) {
CompactionInfo info = new CompactionInfo();
info.dbname = rs.getString(1);
info.tableName = rs.getString(2);
info.partName = rs.getString(3);
response.add(info);
}
// Check for aborted txns
s =
"select tc_database, tc_table, tc_partition "
+ "from TXNS, TXN_COMPONENTS "
+ "where txn_id = tc_txnid and txn_state = '"
+ TXN_ABORTED
+ "' "
+ "group by tc_database, tc_table, tc_partition "
+ "having count(*) > "
+ maxAborted;
LOG.debug("Going to execute query <" + s + ">");
rs = stmt.executeQuery(s);
while (rs.next()) {
CompactionInfo info = new CompactionInfo();
info.dbname = rs.getString(1);
info.tableName = rs.getString(2);
info.partName = rs.getString(3);
info.tooManyAborts = true;
response.add(info);
}
LOG.debug("Going to rollback");
dbConn.rollback();
} catch (SQLException e) {
LOG.error("Unable to connect to transaction database " + e.getMessage());
} finally {
closeDbConn(dbConn);
}
return response;
}
/** Clean up aborted transactions from txns that have no components in txn_components. */
public void cleanEmptyAbortedTxns() throws MetaException {
try {
Connection dbConn = getDbConn();
try {
Statement stmt = dbConn.createStatement();
String s =
"select txn_id from TXNS where "
+ "txn_id not in (select tc_txnid from TXN_COMPONENTS) and "
+ "txn_state = '"
+ TXN_ABORTED
+ "'";
LOG.debug("Going to execute query <" + s + ">");
ResultSet rs = stmt.executeQuery(s);
Set<Long> txnids = new HashSet<Long>();
while (rs.next()) txnids.add(rs.getLong(1));
if (txnids.size() > 0) {
StringBuffer buf = new StringBuffer("delete from TXNS where txn_id in (");
boolean first = true;
for (long tid : txnids) {
if (first) first = false;
else buf.append(", ");
buf.append(tid);
}
buf.append(")");
LOG.debug("Going to execute update <" + buf.toString() + ">");
int rc = stmt.executeUpdate(buf.toString());
LOG.debug("Removed " + rc + " records from txns");
LOG.debug("Going to commit");
dbConn.commit();
}
} catch (SQLException e) {
LOG.error("Unable to delete from txns table " + e.getMessage());
LOG.debug("Going to rollback");
try {
dbConn.rollback();
} catch (SQLException e1) {
}
detectDeadlock(e, "cleanEmptyAbortedTxns");
throw new MetaException(
"Unable to connect to transaction database " + StringUtils.stringifyException(e));
} finally {
closeDbConn(dbConn);
}
} catch (DeadlockException e) {
cleanEmptyAbortedTxns();
} finally {
deadlockCnt = 0;
}
}
/**
* Find entries in the queue that are ready to be cleaned.
*
* @return information on the entry in the queue.
*/
public List<CompactionInfo> findReadyToClean() throws MetaException {
Connection dbConn = getDbConn();
List<CompactionInfo> rc = new ArrayList<CompactionInfo>();
try {
Statement stmt = dbConn.createStatement();
String s =
"select cq_id, cq_database, cq_table, cq_partition, "
+ "cq_type, cq_run_as from COMPACTION_QUEUE where cq_state = '"
+ READY_FOR_CLEANING
+ "'";
LOG.debug("Going to execute query <" + s + ">");
ResultSet rs = stmt.executeQuery(s);
while (rs.next()) {
CompactionInfo info = new CompactionInfo();
info.id = rs.getLong(1);
info.dbname = rs.getString(2);
info.tableName = rs.getString(3);
info.partName = rs.getString(4);
switch (rs.getString(5).charAt(0)) {
case MAJOR_TYPE:
info.type = CompactionType.MAJOR;
break;
case MINOR_TYPE:
info.type = CompactionType.MINOR;
break;
default:
throw new MetaException("Unexpected compaction type " + rs.getString(5));
}
info.runAs = rs.getString(6);
rc.add(info);
}
LOG.debug("Going to rollback");
dbConn.rollback();
return rc;
} catch (SQLException e) {
LOG.error("Unable to select next element for cleaning, " + e.getMessage());
try {
LOG.debug("Going to rollback");
dbConn.rollback();
} catch (SQLException e1) {
}
throw new MetaException(
"Unable to connect to transaction database " + StringUtils.stringifyException(e));
} finally {
closeDbConn(dbConn);
}
}
/**
* This will remove an entry from the queue after it has been compacted.
*
* @param info info on the compaction entry to remove
*/
public void markCleaned(CompactionInfo info) throws MetaException {
try {
Connection dbConn = getDbConn();
try {
Statement stmt = dbConn.createStatement();
String s = "delete from COMPACTION_QUEUE where cq_id = " + info.id;
LOG.debug("Going to execute update <" + s + ">");
if (stmt.executeUpdate(s) != 1) {
LOG.error("Unable to delete compaction record");
LOG.debug("Going to rollback");
dbConn.rollback();
}
// Remove entries from completed_txn_components as well, so we don't start looking there
// again.
s =
"delete from COMPLETED_TXN_COMPONENTS where ctc_database = '"
+ info.dbname
+ "' and "
+ "ctc_table = '"
+ info.tableName
+ "'";
if (info.partName != null) {
s += " and ctc_partition = '" + info.partName + "'";
}
LOG.debug("Going to execute update <" + s + ">");
if (stmt.executeUpdate(s) < 1) {
LOG.error(
"Expected to remove at least one row from completed_txn_components when "
+ "marking compaction entry as clean!");
}
s =
"select txn_id from TXNS, TXN_COMPONENTS where txn_id = tc_txnid and txn_state = '"
+ TXN_ABORTED
+ "' and tc_database = '"
+ info.dbname
+ "' and tc_table = '"
+ info.tableName
+ "'";
if (info.partName != null) s += " and tc_partition = '" + info.partName + "'";
LOG.debug("Going to execute update <" + s + ">");
ResultSet rs = stmt.executeQuery(s);
Set<Long> txnids = new HashSet<Long>();
while (rs.next()) txnids.add(rs.getLong(1));
if (txnids.size() > 0) {
// Remove entries from txn_components, as there may be aborted txn components
StringBuffer buf = new StringBuffer();
buf.append("delete from TXN_COMPONENTS where tc_txnid in (");
boolean first = true;
for (long id : txnids) {
if (first) first = false;
else buf.append(", ");
buf.append(id);
}
buf.append(") and tc_database = '");
buf.append(info.dbname);
buf.append("' and tc_table = '");
buf.append(info.tableName);
buf.append("'");
if (info.partName != null) {
buf.append(" and tc_partition = '");
buf.append(info.partName);
buf.append("'");
}
LOG.debug("Going to execute update <" + buf.toString() + ">");
int rc = stmt.executeUpdate(buf.toString());
LOG.debug("Removed " + rc + " records from txn_components");
// Don't bother cleaning from the txns table. A separate call will do that. We don't
// know here which txns still have components from other tables or partitions in the
// table, so we don't know which ones we can and cannot clean.
}
LOG.debug("Going to commit");
dbConn.commit();
} catch (SQLException e) {
try {
LOG.error("Unable to delete from compaction queue " + e.getMessage());
LOG.debug("Going to rollback");
dbConn.rollback();
} catch (SQLException e1) {
}
detectDeadlock(e, "markCleaned");
throw new MetaException(
"Unable to connect to transaction database " + StringUtils.stringifyException(e));
} finally {
closeDbConn(dbConn);
}
} catch (DeadlockException e) {
markCleaned(info);
} finally {
deadlockCnt = 0;
}
}
/**
* This will grab the next compaction request off of the queue, and assign it to the worker.
*
* @param workerId id of the worker calling this, will be recorded in the db
* @return an info element for this compaction request, or null if there is no work to do now.
*/
public CompactionInfo findNextToCompact(String workerId) throws MetaException {
try {
Connection dbConn = getDbConn();
CompactionInfo info = new CompactionInfo();
try {
Statement stmt = dbConn.createStatement();
String s =
"select cq_id, cq_database, cq_table, cq_partition, "
+ "cq_type from COMPACTION_QUEUE where cq_state = '"
+ INITIATED_STATE
+ "' for update";
LOG.debug("Going to execute query <" + s + ">");
ResultSet rs = stmt.executeQuery(s);
if (!rs.next()) {
LOG.debug("No compactions found ready to compact");
dbConn.rollback();
return null;
}
info.id = rs.getLong(1);
info.dbname = rs.getString(2);
info.tableName = rs.getString(3);
info.partName = rs.getString(4);
switch (rs.getString(5).charAt(0)) {
case MAJOR_TYPE:
info.type = CompactionType.MAJOR;
break;
case MINOR_TYPE:
info.type = CompactionType.MINOR;
break;
default:
throw new MetaException("Unexpected compaction type " + rs.getString(5));
}
// Now, update this record as being worked on by this worker.
long now = System.currentTimeMillis();
s =
"update COMPACTION_QUEUE set cq_worker_id = '"
+ workerId
+ "', "
+ "cq_start = "
+ now
+ ", cq_state = '"
+ WORKING_STATE
+ "' where cq_id = "
+ info.id;
LOG.debug("Going to execute update <" + s + ">");
if (stmt.executeUpdate(s) != 1) {
LOG.error("Unable to update compaction record");
LOG.debug("Going to rollback");
dbConn.rollback();
}
LOG.debug("Going to commit");
dbConn.commit();
return info;
} catch (SQLException e) {
LOG.error("Unable to select next element for compaction, " + e.getMessage());
try {
LOG.debug("Going to rollback");
dbConn.rollback();
} catch (SQLException e1) {
}
detectDeadlock(e, "findNextToCompact");
throw new MetaException(
"Unable to connect to transaction database " + StringUtils.stringifyException(e));
} finally {
closeDbConn(dbConn);
}
} catch (DeadlockException e) {
return findNextToCompact(workerId);
} finally {
deadlockCnt = 0;
}
}