Documentation > Debugging > Debugging Java Frontend
Debugging H-Store in Eclipse
The following instructions will allow you to execute a single node H-Store cluster from Eclipse. Note that you must build the EE libraries first from the command-line before you can execute these commands. In this example, we will use the TPC-C benchmark that comes with H-Store.
- After starting Eclipse, right click on HStore.java and select Debug As → Java Application. Create a new debug configuration for HStore with the following parameters:
- Program Arguments:
catalog.jar=tpcc.jar site.id=0 conf=properties/default.properties
- VM Arguments:
-ea -server -Xmx2048m -Xcheck:jni -Djava.library.path=obj/release/nativelibs
- Working Directory: File System →
/path/to/h-store
- Program Arguments:
- Build H-Store and create the TPC-C project catalog:
ant hstore-prepare -Dproject=tpcc -Dhosts=localhost:0:0-1
- Execute the HStore profile target in Eclipse. Once it prints the message “Site is ready for action“, it is ready for new incoming connections. You can test that the database is online by executing the following command:
ant hstore-invoke -Dproject=tpcc -Dproc="@NoOp"
- You can now use H-Store’s BenchmarkController to load data into the database. The following command will connect to the cluster running in Eclipse, load data for the target benchmark, and then immediately exit.
ant hstore-benchmark -Dproject=tpcc -Dnosites=true -Dnoexecute=true
Multi-Node Clusters:
You can also debug a multi-node cluster in Eclipse. In this example, we will create a two site cluster on the same machine and then launch one of the sites in Eclipse and one of the sites from the command-line. Note that the two sites do not need to be on the same machine, but for simplicity we will assume that they are.
- Create a two-node / two-site / two-partition cluster project jar:
ant hstore-prepare -Dproject=tpcc -Dhosts="localhost:0:0;localhost:1:1"
- Start the first HStoreSite in Eclipse using the instructions above.
- Immediately start the second HStoreSite from the command-line using the following command. The nostart option is a comma-separated list of the sites that should not be started by the BenchmarkController. This must be executed right after the first HStoreSite is started in Eclipse so that the two sites can find each other on the network.
ant hstore-benchmark -Dproject=tpcc -Dnoloader=true -Dnoshutdown=true -Dnostart=0
- Once the first site prints the message “Site is ready for action” in the Eclipse console, you can then test that the database is online by executing the following command:
ant hstore-invoke -Dproject=tpcc -Dproc="@NoOp"
H-Store Status Thread
In order to better understand what each HStoreSite is doing at run time, you can use the HStoreSiteStatus feature to print non-blocking debug information about the current status of the system.
The functionality of HStoreSiteStatus can be controlled with the following H-Store configuration parameters. The site.status_show_txn_info, site.status_show_executor_info, and site.status_show_thread_info options can be used to control the amount of information printed in each status update. Note that although this additional information does not cause the system to block, there is increased overhead for adding this throttling information.
| site.status_enable | If set to true, then this will enable the HStoreSiteStatus thread. |
| site.status_interval | How often (in milliseconds) will the HStoreSiteStatus print an update. |
| site.status_kill_if_hung | Allow the HStoreSiteStatus thread to kill the cluster if the local HStoreSite appears to be hung. |
| site.status_show_txn_info | Print a summarization table of how transactions were executed. This includes information such as the number of transactions that were single-partitioned, multi-partitioned, speculatively executed, and committed/aborted. |
| site.status_show_executor_info | Print information about each PartitionExecutor. This includes information such as the amount of time that the execution thread was blocked waiting for work, the average time it took to execute transactions. |
| site.status_show_thread_info | Print abbreviated stack traces for all of the threads running at a site. |
| site.status_check_for_zombies | Allow the HStoreSiteStatus thread to check whether there any zombie transactions. This can occur if the transaction has already sent back the ClientResponse, but its internal state has not been cleaned up. |
For example, the following command will execute the TM1 benchmark and have each HStoreSite in the cluster print out a summary table about transactions every 10 seconds. The table will appear in the site’s log files (site.log_dir)
ant hstore-benchmark -Dproject=tm1 \ -Dsite.status_enable=true \ -Dsite.status_interval=10000 \ -Dsite.status_show_txn_info=true
And example of this table is show below:
**************************************************************************************************************************************************************** * HStoreSite Status: H01 * * Number of Partitions: 1 * * ------------------------------------------------------------------------------------------------------------------------------------------------------------ * * Completed Txns: 229955 * * # of Connections: 12 * * Client Interface Queue: 190 txns [limit=1500, release=1200, bytes=13198] * * InFlight Txns: 53188 total / 270 dtxn / 0 finished [totalMin=0, totalMax=53188] * * ------------------------------------------------------------------------------------------------------------------------------------------------------------ * * RECEIVED REJECTED REDIRECTED EXECUTED | SINGLE-P MULTI-P | COMPLETED ABORTED RESTARTED MISPREDICTED | SPECULATIVE NO-UNDO * * @GarbageCollection: 1 - - 2 | - - | 1 - - - | - - * * @LoadMultipartitionTable: 83 - - 166 | - - | 83 - - - | - - * * @ResetProfiling: 1 - - 2 | - - | 1 - - - | - - * * DeleteCallForwarding: 13557 9210 4248 12722 | - 21 | 21 - 915 11733 | 915 - * * GetAccessData: 108922 9039 - 99994 | 99916 - | 99916 - 78 - | 7507 99994 * * GetNewDestination: 30813 2586 - 28267 | 28239 - | 28239 - 28 - | 2074 28267 * * GetSubscriberData: 108661 9112 - 99641 | 99569 - | 99569 - 72 - | 7595 99641 * * InsertCallForwarding: 8947 6107 2789 8367 | - 29 | 29 - 549 7784 | 549 - * * UpdateLocation: 63567 43059 20115 59821 | - 311 | 311 - 4189 55321 | 4189 - * * UpdateSubscriberData: 3109 282 - 2830 | 2827 - | 1785 1042 3 - | 232 - * * -----------------------------------------------------------------------------------------------------------------------------------* * TOTAL: 337661 79395 27152 311812 | 230551 361 | 229955 1042 5834 74838 | 23061 227902 * * 0.235 0.080 0.923 | 0.998 0.002 | 0.003 0.019 0.240 | 0.100 0.731 * ****************************************************************************************************************************************************************
