Hyper-Q System Log File
The Hyper-Q system log file contains metrics about the operational status of Hyper-Q. Hyper-Q records the collected metrics to the file at approximately five second intervals, and each live in the file is a snapshot of the metrics at the indicated time.
The system log is a comma-separated values (CSV) file, a delimited text file that uses a comma to separate values. Each line of the file is a data record. Each record consists of one or more fields, separated by commas.
Column Name | Description |
|---|---|
timestamp | The timestamp when the event occurred, using the local server timezone and formatted with millisecond-precision timestamps as: YYYY-MM-DD HH:MM:SS.mmm |
session_count | The number of active client sessions connecting to Hyper-Q. |
lsn_count | The number of concurrent bulk import and export sessions. |
process_count | The number of running Erlang processes. |
port_count | The number of open network sockets, files, and external processes. |
cpu_util | Percentage of CPU utilization as reported by the operating system kernel for all operating system processes. |
mem_util | Percentage of memory utilization of all operating system processes on the host system. |
reductions | Amount of computation performed since the last entry. |
io_input | The number of bytes read from network sockets since the last entry. |
io_output | The number of bytes written to network sockets since the last entry. |
sds_file_writer_out | The number of bytes written to bulk import staging files since the last entry. |
sds_result_device_out | The the total size in bytes written to result spill files since the last entry. Spill files save intermediate results when there is insufficient memory to execute a query in memory. Disk I/O is much slower than memory access, so a query that creates spill files will take longer to complete. |
mem_alloc | Total memory allocated to Erlang carriers. A carrier is a portion of memory allocated from either the operating system or a super carrier (see note). There are two types of carriers: single-block carriers which only contain one large block, and multi-block carriers which contain multiple blocks. To learn more about memory allocation in Erlang, see the following resources:
NoteThe mem_alloc metric does not count super carriers. A super carrier is a large memory area allocated when starting the Erlang virtual machine that can be used during runtime to allocate memory to normal carriers. To learn more about super carriers, see Super Carrier in the Erlang documentation. |
total | The total amount of memory in bytes allocated to Hyper-Q. |
processes | The total amount of memory in bytes allocated to Erlang processes. |
processes_used | The total amount of memory in bytes currently in use by Erlang processes. |
system | The total amount of system overhead memory in bytes. |
atom | The total amount of memory in bytes allocated to the atom table. This is a portion of the system memory. An atom table is a system-defined table that stores strings and corresponding identifiers. An application places a string in an atom table and receives a 16-bit integer, called an atom, that can be used to access the string. To learn more about atom tables and memory usage, see Memory in the the Erlang documentation. |
atom_used | The total amount of memory in bytes used by atoms in the atom table. This is a portion of the system memory. |
binary | The total amount of memory in bytes used for binary data. This is a portion of the system memory. |
code | The total amount of memory in bytes used for executable code. This is a portion of the system memory. |
ets | The total amount of memory in bytes used for Erlang Term Storage (ETS) tables. This is a portion of the system memory. ETS can store large amounts of data and provides constant time data access. Tables in ETS are created and owned by individual processes. When an owner process terminates, its tables are destroyed. You can have as many ETS table as you want, the only limit is the server memory. To learn more about ETS tables, see ETS and Memory in the Erlang documentation. |