Documentation > Deployment > Transaction Trace Logs

H-Store supports the ability to write all transaction executions to JSON-based trace files.

Note that these logs are not used for recovery, but are rather for post-processing and other database design tools provided by H-Store.

Command-line Arguments

When executing a benchmark, use the trace option to specify the file path where each HStoreSite will write their transaction logs. The site id of each HStoreSite instance will be appended to the value of trace option. For example, assume the target cluster below has four execution sites running on four different machines:

ant hstore-benchmark -Dproject=$BENCHMARK -Dtrace=/path/to/tpcc.log

Each HStoreSite will create a new file /path/to/tpcc.log-X relative to base directory of where H-Store is deployed from (where X is the site id that produced the file).

You can also configure H-Store to ignore certain transactions when creating the trace logs by changing the workload.ignore property in the benchmark property files.

Combining Multiple Traces into a Single File

After executing a benchmark multiple times or on multiple machines, you may want to combine the multiple trace files into a single file. The workload-combine command can be used to do this. The workload option specifies the input files that you want to combine together, and the output command is where the combined files will be written to. You can use the wildcard character (*) for the input value.

ant workload-combine -Dproject=$BENCHMARK -Dworkload=/path/to/tpcc.log* -Doutput=tpcc.combined

JSON Format

The following is the JSON schema of the transaction and query traces generated by H-Store.

<transaction> = {
   "TxnId":     <integer>,      // Unique Transaction Identifier
   "Name":      <string>,       // Stored Procedure Name
   "Start":     <integer>,      // Transaction Start Time
   "Stop":      <integer>,      // Transaction Stop Time
   "Aborted":   <boolean>       // True if Transaction was Aborted
   "Params":    [ <param>* ],   // Stored Procedure Input Parameters
   "Queries":   [ <query>* ],   // Queries Executed in Transaction
   "Output":    [ <output>* ],  // Optional final output for Transaction
}
<query> = {
   "Name":      <string>,       // Query Name
   "Batch":     <integer>,      // Optional Batch Identifier (Starting at zero)
   "Start":     <integer>,      // Query Start Time
   "Stop":      <integer>,      // Query Stop Time
   "Aborted":   <boolean>       // True if Query was Aborted
   "Params":    [ <param>* ],   // Query Input Parameters
   "Output":    [ <output>* ],  // Optional result for Query
}
<output> = {
   "Types":     [ <string>* ],     // List of output types for data columns
   "Data":      [ [ <param>* ]* ], // List of data row lists
}
<param> = [ <integer>|<string>|<timestamp>|<boolean> ]*

Transaction Record Fields

Query Record Fields

Sample Workloads

Previously executed workload traces for H-Store’s built-in benchmarks are available from the supplemental research files repository.