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https://issues.apache.org/jira/browse/HIVE-23671?focusedWorklogId=452867&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-452867
]
ASF GitHub Bot logged work on HIVE-23671:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Jun/20 08:36
Start Date: 30/Jun/20 08:36
Worklog Time Spent: 10m
Work Description: deniskuzZ commented on a change in pull request #1087:
URL: https://github.com/apache/hive/pull/1087#discussion_r447509066
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/txn/TxnHandler.java
##########
@@ -2032,28 +2077,61 @@ public void
seedWriteIdOnAcidConversion(InitializeTableWriteIdsRequest rqst)
// The initial value for write id should be 1 and hence we add 1 with
number of write ids
// allocated here
String s = "INSERT INTO \"NEXT_WRITE_ID\" (\"NWI_DATABASE\",
\"NWI_TABLE\", \"NWI_NEXT\") VALUES (?, ?, "
- + Long.toString(rqst.getSeeWriteId() + 1) + ")";
- pst = sqlGenerator.prepareStmtWithParameters(dbConn, s,
Arrays.asList(rqst.getDbName(), rqst.getTblName()));
+ + Long.toString(rqst.getSeedWriteId() + 1) + ")";
+ pst = sqlGenerator.prepareStmtWithParameters(dbConn, s,
Arrays.asList(rqst.getDbName(), rqst.getTableName()));
LOG.debug("Going to execute insert <" + s.replaceAll("\\?", "{}") +
">",
- quoteString(rqst.getDbName()), quoteString(rqst.getTblName()));
+ quoteString(rqst.getDbName()),
quoteString(rqst.getTableName()));
pst.execute();
LOG.debug("Going to commit");
dbConn.commit();
} catch (SQLException e) {
- LOG.debug("Going to rollback");
rollbackDBConn(dbConn);
- checkRetryable(dbConn, e, "seedWriteIdOnAcidConversion(" + rqst + ")");
- throw new MetaException("Unable to update transaction database "
- + StringUtils.stringifyException(e));
+ checkRetryable(dbConn, e, "seedWriteId(" + rqst + ")");
+ throw new MetaException("Unable to update transaction database " +
StringUtils.stringifyException(e));
} finally {
close(null, pst, dbConn);
unlockInternal();
}
} catch (RetryException e) {
- seedWriteIdOnAcidConversion(rqst);
+ seedWriteId(rqst);
}
+ }
+
+ @Override
+ public void seedTxnId(SeedTxnIdRequest rqst) throws MetaException {
+ try {
+ Connection dbConn = null;
+ Statement stmt = null;
+ try {
+ lockInternal();
+ dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED);
+ stmt = dbConn.createStatement();
+ /*
+ * Locking the txnLock an exclusive way, we do not want to set the
txnId backward accidentally
+ * if there are concurrent open transactions
+ */
+ acquireTxnLock(stmt, false);
+ long highWaterMark = getHighWaterMark(stmt);
+ if (highWaterMark >= rqst.getSeedTxnId()) {
Review comment:
not quite understand this if condition. You have check in
validateAndAddMaxTxnIdAndWriteId() if there are already some write ids
registered in HMS and we try to do repair - throw exception. Could it be
possible due to lack of locking that when we calculate the write ids there is
nothing in HMS, however when we try to seed - some transaction generates a new
write id - would it cause some dataloss problems or other issues?
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Issue Time Tracking
-------------------
Worklog Id: (was: 452867)
Time Spent: 6h 50m (was: 6h 40m)
> MSCK repair should handle transactional tables in certain usecases
> ------------------------------------------------------------------
>
> Key: HIVE-23671
> URL: https://issues.apache.org/jira/browse/HIVE-23671
> Project: Hive
> Issue Type: Improvement
> Components: Metastore
> Reporter: Peter Varga
> Assignee: Peter Varga
> Priority: Major
> Labels: pull-request-available
> Time Spent: 6h 50m
> Remaining Estimate: 0h
>
> The MSCK REPAIR tool does not handle transactional tables too well. It can
> find and add new partitions the same way as for non-transactional tables, but
> since the writeId differences are not handled, the data can not read back
> from the new partitions.
> We could handle some usecases when the writeIds in the HMS and the underlying
> data are not conflicting. If the HMS does not contains allocated writes for
> the table we can seed the table with the writeIds read from the directory
> structrure.
> Real life use cases could be:
> * Copy data files from one cluster to another with different HMS, create the
> table and call MSCK REPAIR
> * If the HMS db is lost, recreate the table and call MSCK REPAIR
>
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