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|
fdb-read
========
Read data from the FDB and write this data into a specified target file. This may involve visiting multiple databases if required by the request.
Usage
-----
::
fdb-read request.mars target.grib
fdb-read --extract source.grib target.grib
Options
-------
+----------------------------------------+-----------------------------------------------------------------------------------------+
| ``--extract`` | Extract the request(s) from an existing GRIB file |
+----------------------------------------+-----------------------------------------------------------------------------------------+
| ``--statistics`` | Report timing statistics |
+----------------------------------------+-----------------------------------------------------------------------------------------+
Examples
--------
Specify the [MARS request](MARS.md) in a plain text file.
Note that this MARS request must be fully expanded. For example, it may not contain the **/to/** or **/by/** statements that the MARS client is able to expand.
::
% cat myrequest
retrieve,class=od,expver=0001,stream=oper,date=20151004,time=1200,domain=g,type=an,levtype=pl,step=0,levelist=700,param=155
# this will retrieve 2 fields
% fdb-read myrequest foo.grib
retrieve,class=od,date=20151004,domain=g,expver=0001,levelist=500/700,levtype=pl,param=155,step=0,stream=oper,time=1200,type=an
Compress handle: 3.3e-05 second elapsed, 3.2e-05 second cpu
Compress handle: 2e-06 second elapsed, 2e-06 second cpu
Read rate: 4.7575 Gbytes per second
Write rate: 2.54081 Gbytes per second
Save into: 0.022224 second elapsed, 0.022182 second cpu
Obtain data from the FDB using the MARS request that would be implied by an existing GRIB file. In this example, foo.grib contains 2 fields that identify what needs to be retrieved.
::
% fdb-read --extract foo.grib out.grib
retrieve,class=od,date=20151004,domain=g,expver=0001,levelist=500,levtype=pl,param=155,step=0,stream=oper,time=1200,type=an
...
Compress handle: 3.3e-05 second elapsed, 3.2e-05 second cpu
Compress handle: 2e-06 second elapsed, 2e-06 second cpu
Read rate: 4.7575 Gbytes per second
Write rate: 2.54081 Gbytes per second
Save into: 0.022224 second elapsed, 0.022182 second cpu
|
