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Hive QA commented on HIVE-15077: -------------------------------- | (x) *{color:red}-1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || || || || || {color:brown} Prechecks {color} || | {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m 0s{color} | {color:blue} Findbugs executables are not available. {color} | | {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s{color} | {color:green} The patch does not contain any @author tags. {color} | || || || || {color:brown} master Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m 44s{color} | {color:blue} Maven dependency ordering for branch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 7m 11s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 54s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 3s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m 43s{color} | {color:green} master passed {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m 8s{color} | {color:blue} Maven dependency ordering for patch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 2m 15s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 39s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m 39s{color} | {color:green} the patch passed {color} | | {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m 44s{color} | {color:red} ql: The patch generated 7 new + 426 unchanged - 0 fixed = 433 total (was 426) {color} | | {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 0m 20s{color} | {color:red} standalone-metastore: The patch generated 2 new + 510 unchanged - 3 fixed = 512 total (was 513) {color} | | {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m 0s{color} | {color:green} The patch has no whitespace issues. {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m 42s{color} | {color:green} the patch passed {color} | || || || || {color:brown} Other Tests {color} || | {color:red}-1{color} | {color:red} asflicense {color} | {color:red} 0m 14s{color} | {color:red} The patch generated 49 ASF License warnings. {color} | | {color:black}{color} | {color:black} {color} | {color:black} 20m 0s{color} | {color:black} {color} | \\ \\ || Subsystem || Report/Notes || | Optional Tests | asflicense javac javadoc findbugs checkstyle compile | | uname | Linux hiveptest-server-upstream 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u1 (2016-09-03) x86_64 GNU/Linux | | Build tool | maven | | Personality | /data/hiveptest/working/yetus/dev-support/hive-personality.sh | | git revision | master / a2d22b4 | | Default Java | 1.8.0_111 | | checkstyle | http://104.198.109.242/logs//PreCommit-HIVE-Build-9219/yetus/diff-checkstyle-ql.txt | | checkstyle | http://104.198.109.242/logs//PreCommit-HIVE-Build-9219/yetus/diff-checkstyle-standalone-metastore.txt | | asflicense | http://104.198.109.242/logs//PreCommit-HIVE-Build-9219/yetus/patch-asflicense-problems.txt | | modules | C: ql standalone-metastore U: . | | Console output | http://104.198.109.242/logs//PreCommit-HIVE-Build-9219/yetus.txt | | Powered by | Apache Yetus http://yetus.apache.org | This message was automatically generated. > Acid LockManager is unfair > -------------------------- > > Key: HIVE-15077 > URL: https://issues.apache.org/jira/browse/HIVE-15077 > Project: Hive > Issue Type: Bug > Components: Transactions > Affects Versions: 2.3.0 > Reporter: Eugene Koifman > Assignee: Eugene Koifman > Priority: Blocker > Attachments: HIVE-15077.02.patch > > > HIVE-10242 made the acid LM unfair. > In TxnHandler.checkLock(), suppose we are trying to acquire SR5 (the number > is extLockId). > Then > LockInfo[] locks = lockSet.toArray(new LockInfo[lockSet.size()]); > may look like this (all explicitly listed locks are in Waiting state) > {...., SR5 SW3 X4} > So the algorithm will find SR5 in the list and start looking backwards (to > the left). > According to IDs, SR5 should wait for X4 to be granted but X4 won't even be > examined and so SR5 may be granted. > Theoretically, this could cause starvation. > The query that generates the list already has > query.append(" and hl_lock_ext_id <= ").append(extLockId); > but it should use "<" rather than "<=" to exclude the locks being checked > from "locks" list which will make the algorithm look at all locks "in front" > of a given lock. > Here is an example (add to TestDbTxnManager2) > {noformat} > @Test > public void testFairness2() throws Exception { > dropTable(new String[]{"T7"}); > CommandProcessorResponse cpr = driver.run("create table if not exists T7 > (a int) partitioned by (p int) stored as orc TBLPROPERTIES > ('transactional'='true')"); > checkCmdOnDriver(cpr); > checkCmdOnDriver(driver.run("insert into T7 partition(p) > values(1,1),(1,2)"));//create 2 partitions > cpr = driver.compileAndRespond("select a from T7 "); > checkCmdOnDriver(cpr); > txnMgr.acquireLocks(driver.getPlan(), ctx, "Fifer");//gets S lock on T7 > HiveTxnManager txnMgr2 = > TxnManagerFactory.getTxnManagerFactory().getTxnManager(conf); > swapTxnManager(txnMgr2); > cpr = driver.compileAndRespond("alter table T7 drop partition (p=1)"); > checkCmdOnDriver(cpr); > //tries to get X lock on T7.p=1 and gets Waiting state > LockState lockState = ((DbTxnManager) > txnMgr2).acquireLocks(driver.getPlan(), ctx, "Fiddler", false); > List<ShowLocksResponseElement> locks = getLocks(); > Assert.assertEquals("Unexpected lock count", 4, locks.size()); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > null, locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=1", locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=2", locks); > checkLock(LockType.EXCLUSIVE, LockState.WAITING, "default", "T7", "p=1", > locks); > HiveTxnManager txnMgr3 = > TxnManagerFactory.getTxnManagerFactory().getTxnManager(conf); > swapTxnManager(txnMgr3); > //this should block behind the X lock on T7.p=1 > cpr = driver.compileAndRespond("select a from T7"); > checkCmdOnDriver(cpr); > txnMgr3.acquireLocks(driver.getPlan(), ctx, "Fifer");//gets S lock on T6 > locks = getLocks(); > Assert.assertEquals("Unexpected lock count", 7, locks.size()); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > null, locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=1", locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=2", locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > null, locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=1", locks); > checkLock(LockType.SHARED_READ, LockState.ACQUIRED, "default", "T7", > "p=2", locks); > checkLock(LockType.EXCLUSIVE, LockState.WAITING, "default", "T7", "p=1", > locks); > } > {noformat} > The 2nd {{locks = getLocks();}} output shows that all locks for the 2nd > {{select * from T7}} are all acquired while they should block behind the X > lock to be fair. -- This message was sent by Atlassian JIRA (v7.6.3#76005)