This is the first time I try to use english to write my blog, so don’t jeer at the mistake of my grammar and spelling.
Because of multi threaded drelephant will cause JobHistoryServer’s Loads very high, so I stopped it for a strench of time. Until last week, a period pull from JHS patch merge request from github was released. I re-compiled dr. elephant and deploy the new dr. elephant on the cluster. It seems stable, but on this Monday morning, my leader told me that there were no more counters and any information about cluster jobs in dr. elephant. So I logged in to the server, and check log, then I found this message below.
[error] c.j.b.ConnectionHandle - Database access problem. Killing off this connection and all remaining connections in the connection pool. SQL State = HY000
And then, I found two things will cause this issue, one of them is selinux config is set to enforcing, change this config value to disabled and reboot the server, it seem good, but still got same error, only not too many.
Then I review the code of dr. elephant, I find out that create table in mysql initializing script of play framework has an issue. the index is too long, I change the index to 250 previously, but if an url is longer then 250, it gone wrong.
create index yarn_app_result_i4 on yarn_app_result (flow_exec_id(250)); create index yarn_app_result_i5 on yarn_app_result (job_def_id(250)); create index yarn_app_result_i6 on yarn_app_result (flow_def_id(250));
So I delete this index limitation, and rewrite the sql like this, add a innodb_large_prefix and row_format=dynamic to the table creation script, and finally, no more error log appears…
SET GLOBAL innodb_file_format=Barracuda; SET GLOBAL innodb_large_prefix = ON; CREATE TABLE yarn_app_result ( id VARCHAR(50) NOT NULL COMMENT 'The application id, e.g., application_1236543456321_1234567', name VARCHAR(100) NOT NULL COMMENT 'The application name', username VARCHAR(50) NOT NULL COMMENT 'The user who started the application', queue_name VARCHAR(50) DEFAULT NULL COMMENT 'The queue the application was submitted to', start_time BIGINT UNSIGNED NOT NULL COMMENT 'The time in which application started', finish_time BIGINT UNSIGNED NOT NULL COMMENT 'The time in which application finished', tracking_url VARCHAR(255) NOT NULL COMMENT 'The web URL that can be used to track the application', job_type VARCHAR(20) NOT NULL COMMENT 'The Job Type e.g, Pig, Hive, Spark, HadoopJava', severity TINYINT(2) UNSIGNED NOT NULL COMMENT 'Aggregate severity of all the heuristics. Ranges from 0(LOW) to 4(CRITICAL)', score MEDIUMINT(9) UNSIGNED DEFAULT 0 COMMENT 'The application score which is the sum of heuristic scores', workflow_depth TINYINT(2) UNSIGNED DEFAULT 0 COMMENT 'The application depth in the scheduled flow. Depth starts from 0', scheduler VARCHAR(20) DEFAULT NULL COMMENT 'The scheduler which triggered the application', job_name VARCHAR(255) NOT NULL DEFAULT '' COMMENT 'The name of the job in the flow to which this app belongs', job_exec_id VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A unique reference to a specific execution of the job/action(job in the workflow). This should filter all applications (mapreduce/spark) triggered by the job for a particular execution.', flow_exec_id VARCHAR(255) NOT NULL DEFAULT '' COMMENT 'A unique reference to a specific flow execution. This should filter all applications fired by a particular flow execution. Note that if the scheduler supports sub- workflows, then this ID should be the super parent flow execution id that triggered the the applications and sub-workflows.', job_def_id VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A unique reference to the job in the entire flow independent of the execution. This should filter all the applications(mapreduce/spark) triggered by the job for al l the historic executions of that job.', flow_def_id VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A unique reference to the entire flow independent of any execution. This should filter all the historic mr jobs belonging to the flow. Note that if your scheduler supports sub-workflows, then this ID should reference the super parent flow that triggered the all the jobs and sub-workflows.', job_exec_url VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A url to the job execution on the scheduler', flow_exec_url VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A url to the flow execution on the scheduler', job_def_url VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A url to the job definition on the scheduler', flow_def_url VARCHAR(800) NOT NULL DEFAULT '' COMMENT 'A url to the flow definition on the scheduler', PRIMARY KEY (id) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC; create index yarn_app_result_i1 on yarn_app_result (finish_time); create index yarn_app_result_i2 on yarn_app_result (username,finish_time); create index yarn_app_result_i3 on yarn_app_result (job_type,username,finish_time); create index yarn_app_result_i4 on yarn_app_result (flow_exec_id); create index yarn_app_result_i5 on yarn_app_result (job_def_id); create index yarn_app_result_i6 on yarn_app_result (flow_def_id); create index yarn_app_result_i7 on yarn_app_result (start_time); CREATE TABLE yarn_app_heuristic_result ( id INT(11) NOT NULL AUTO_INCREMENT COMMENT 'The application heuristic result id', yarn_app_result_id VARCHAR(50) NOT NULL COMMENT 'The application id', heuristic_class VARCHAR(255) NOT NULL COMMENT 'Name of the JVM class that implements this heuristic', heuristic_name VARCHAR(128) NOT NULL COMMENT 'The heuristic name', severity TINYINT(2) UNSIGNED NOT NULL COMMENT 'The heuristic severity ranging from 0(LOW) to 4(CRITICAL)', score MEDIUMINT(9) UNSIGNED DEFAULT 0 COMMENT 'The heuristic score for the application. score = severity * number_of_tasks(map/reduce) where severity not in [0,1], otherwise score = 0', PRIMARY KEY (id), CONSTRAINT yarn_app_heuristic_result_f1 FOREIGN KEY (yarn_app_result_id) REFERENCES yarn_app_result (id) ); create index yarn_app_heuristic_result_i1 on yarn_app_heuristic_result (yarn_app_result_id); create index yarn_app_heuristic_result_i2 on yarn_app_heuristic_result (heuristic_name,severity); CREATE TABLE yarn_app_heuristic_result_details ( yarn_app_heuristic_result_id INT(11) NOT NULL COMMENT 'The application heuristic result id', name VARCHAR(128) NOT NULL DEFAULT '' COMMENT 'The analysis detail entry name/key', value VARCHAR(255) NOT NULL DEFAULT '' COMMENT 'The analysis detail value corresponding to the name', details TEXT COMMENT 'More information on analysis details. e.g, stacktrace', PRIMARY KEY (yarn_app_heuristic_result_id,name), CONSTRAINT yarn_app_heuristic_result_details_f1 FOREIGN KEY (yarn_app_heuristic_result_id) REFERENCES yarn_app_heuristic_result (id) ); create index yarn_app_heuristic_result_details_i1 on yarn_app_heuristic_result_details (name);
At last I send a pull request to linkedin on github.com…