Anne Yu created SENTRY-1007:
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Summary: Sentry column-level performance for wide tables
Key: SENTRY-1007
URL: https://issues.apache.org/jira/browse/SENTRY-1007
Project: Sentry
Issue Type: Bug
Affects Versions: 1.5.1
Reporter: Anne Yu
Priority: Critical
It appears a query is taking a long time on a wide table due many Sentry
column-level auth checks.
here are some investigation results:
1) create a table with 4000 columns, grant select on [table|db] to test user,
however {noformat}select * from table{noformat} still validates column level
privilege on each column. So this select command issues 4000 queries to
validate column level permissions. It takes 40 seconds on my test cluster (2x
large) to return results, for a moment, query seems to freeze:
{noformat}
...
2016-01-11 11:54:14,816 INFO DataNucleus.Query: Reading in results for query
"SELECT FROM org.apache.sentry.provider.db.service.model.MSentryPrivilege WHERE
roles.contains(role) && (role.roleName == "test_role") && serverName ==
"server1" && ((dbName == "test_db") || (dbName == "__NULL__")) && (URI ==
"__NULL__") && ((tableName == "test_tb") || (tableName == "__NULL__")) && (URI
== "__NULL__") && ((columnName == "test997") || (columnName == "__NULL__")) &&
(URI == "__NULL__") VARIABLES
org.apache.sentry.provider.db.service.model.MSentryRole role" since the
connection used is closing
2016-01-11 11:54:14,822 INFO DataNucleus.Query: Reading in results for query
"SELECT FROM org.apache.sentry.provider.db.service.model.MSentryPrivilege WHERE
roles.contains(role) && (role.roleName == "test_role") && serverName ==
"server1" && ((dbName == "test_db") || (dbName == "__NULL__")) && (URI ==
"__NULL__") && ((tableName == "test_tb") || (tableName == "__NULL__")) && (URI
== "__NULL__") && ((columnName == "test998") || (columnName == "__NULL__")) &&
(URI == "__NULL__") VARIABLES
org.apache.sentry.provider.db.service.model.MSentryRole role" since the
connection used is closing
2016-01-11 11:54:14,828 INFO DataNucleus.Query: Reading in results for query
"SELECT FROM org.apache.sentry.provider.db.service.model.MSentryPrivilege WHERE
roles.contains(role) && (role.roleName == "test_role") && serverName ==
"server1" && ((dbName == "test_db") || (dbName == "__NULL__")) && (URI ==
"__NULL__") && ((tableName == "test_tb") || (tableName == "__NULL__")) && (URI
== "__NULL__") && ((columnName == "test999") || (columnName == "__NULL__")) &&
(URI == "__NULL__") VARIABLES
org.apache.sentry.provider.db.service.model.MSentryRole role" since the
connection used is closing
{noformat}
Here is the debug log from sentry service:
{noformat}
org.apache.sentry.binding.hive.authz.HiveAuthzBinding.authorize(HiveAuthzBinding.java:304)]
requiredInputPrivileges = {Table=[SELECT], Column=[SELECT], URI=[ALL]}
{noformat}
2) the same issue for {noformat}show columns in table{noformat}
3) for {noformat}show count(*) in table{noformat}, it requires table level
privilege, so this issue doesn't exist.
4) I found out there are more commands have the same issues are:
{code}
SHOW COLUMNS FROM test_tb1;
create table test_tb2 as select * from test_tb1
show partitions in test_tb1
select * from test_tb1
{code}
Even for {code}select col1,col2,col3 from test_tb1{code} will issue 3 queries
for each column, instead of one query for all columns in one table;
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