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fdbcstat

fdbcstat is a FoundationDB client monitoring tool which collects and displays transaction operation statistics inside the C API library (libfdb_c.so).

How it works

fdbcstat utilizes eBPF/bcc to attach to libfdb_c.so shared library and insert special instructions to collect statistics in several common fdb_transaction_* calls, then it periodically displays the aggregated statistics.

How to use

Syntax

fdbcstat <full path to libfdb_c.so> <options...>

Options

-p or --pid : Only capture statistics for the functions called by the specified process
-i or --interval : Specify the time interval in seconds between 2 outputs (Default: 1)
-d or --duration : Specify the total duration in seconds fdbcstats will run (Default: Unset / Forever)
-f or --functions : Specify the comma-separated list of functions to monitor (Default: Unset / All supported functions)

Supported Functions

get
get_range
get_read_version
set
clear
clear_range
commit

Examples

Collect all statistics and display every second

fdbcstat /usr/lib64/libfdb_c.so

Collect all statistics for PID 12345 for 60 seconds with 10 second interval

fdbcstat /usr/lib64/libfdb_c.so -p 12345 -d 60 -i 10

Collect statitics only for get and commit

fdbcstat /usr/lib64/libfdb_c.so -f get,commit

Output Format

Each line contains multiple fields. The first field is the timestamp. Other fields are the statistics for each operation. Each operation field contains the following statistics in a slash (/) separated format.

Function
Number of calls per second
Average latency in microseconds (us)
Maximum latency in microseconds (us)

Note: The latency is computed as the time difference between the start time and the end time of the fdb_transaction_* function call except for get, get_range, get_read_version and commit. For those 4 functions, the latency is the time difference between the start time of the function and the end time of the following fdb_future_block_until_ready call.

Sample Output

...
15:05:31 clear/22426/2/34 commit/18290/859/15977 get/56230/1110/12748 get_range/14141/23/75 set/6276/3/19 
15:05:41 clear/24147/2/38 commit/18259/894/44259 get/57978/1098/15636 get_range/13171/23/90 set/6564/3/15 
15:05:51 clear/21287/2/34 commit/18386/876/17824 get/58318/1106/30539 get_range/13018/23/68 set/6559/3/13 
...

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