Welcome to the Wiki for JSOC software development

For general information including the basic setup to get started see the Users Guide.

Release History

DRMS Data Series

  1. DRMS Overview

  2. Names

  3. JSD Format

  4. JSOC Sessions, Pipelines, and Modules (Oh my!)

    JSOC programs that use DRMS to operate on DataSeries are called "modules". Modules are run in "sessions". HMI and AIA major processing tasks are accomplished in "pipelines" consisting of one or more sessions. Pipelines are started by "PUI" (Pipeline User Interface) usually by the JSOC production team. Pipelines may also be initiated by users requesting DataSets via the web or by team members running locally or remotely. A DataSet is a collection of records selected by a query. In essence a dataset name is simply the query that describes it.

  5. A DRMS Session is the basic unit of computing that interracts with DRMS and SUMS. At the start of a session the user connects to the DRMS database. During the session the user runs one or more modules which read or create

    DataRecords in DataSeries. Access to the actual data stored in SUMS is accomplished within a module via the DRMS API. At the end of a session, SUMS is notified to save any new records online and/or on tape, or to delete records marked temporary to the session.

  6. Actually using the JSOC DRMS requires running a program or module. By "program" we mean a normal shell command and by "module" we mean a program built to run within a DRMS session and communication to a drms_server. There are four types of programs/modules:
    • Modules - Most programs that do the work of the user of JSOC are what we call "modules". On the outside modules look like programs. They must run in a DRMS session. If they are built with the normal jsoc_main program they will use an existing session if they are run from a Session Provider or will start their own use-once session if they are called stand-alone from the shell.

    • Utility programs like create_series and describe_series which are usually used to manage the existence of dataseries, not to use dataseries. These programs talk directly to the database.

    • Session Providers like drms_run or later the Pipeline User Interface start DRMS sessions and execute a script file. They can also be used to execute a single instance of a module.

    • drms_server which connects connects to the database and serves sessions. Most users will not need to start drms_server explicitly.

    The benefit of running programs as "modules" will hopefully become apparent when we start running complex pipelines using hundreds of processors.

General Development Information - Using Modules

  1. DRMS Man Pages All the JSOC "man" pages are now maintained with doxygen, a semi-automatic documentation tool. They are available in html form via:

    All programs and functions have entries in the doxygen generated pages.
  2. Limits

  3. There are limits ...
    • memory limits on number of records in the cache (512Meg / (2.5*record size) ). While this may seem like a lot, for datasets with a lot of keywords (e.g. mdi_vw_V_06h) it can be a real limit to the number of records that can be open at a time. For the vw_V example it means that DRMS_QUERY_MEM should be set to at lest 2500 (yes 2.5 gig) to open 100 days of one-minute data. Modules expecting to need tens of thousands of records opened should arrange to do the work in blocks with drms_close_records used to empty the record cache to free memory.
    • length of names of series, keywords, etc. (64 chars)
    • length of comma sep list of prime key names (1024 chars)
    • length of descriptions of series, keywords, links, and segments (254 chars)
    • length of string values of keywords (dont know)
    • number of keywords in a record (dont know)
    • number of records in a series (no fixed limit)
    • length of segment filename (255 chars)
    • length of path (511 chars)
  4. Log Files - Processing meta-data

  5. There are log files. Stdout and Stderr are captured in files as well as shown during processing (depending on module and -v flag). These are all put into a SUMS directory and indexed in DRMS by session ID. The session ID is stored in each record so the log files can be retrieved if/when needed. Unless otherwise specified, the default retention time for log files is 10 days. The log files are archived if any one of the SUs in the current session is to be archived.
    • drms_server logs --
    • The default is no logging. When the logging option is turned on (-L), stdout and stderr are redirected to files in SU directory.
    • module logs --
    • The default is no logging. When the logging option is turned on (-L), stdout and stderr are tee-ed to files in SU directory.

Software Development - Building Modules

  1. DRMS Applications Programming Interface] Descriptions of the API developed for the underlying JSOC database, and how to code with it.

    • DRMS API summary - old

    • DRMS API Manual -- More detailed information for users and developers of specific JSOC software programs or interfaces using the Doxygen tools. Please use the search engine there to find documentations for any API functions.


  3. JSOC Software Tree

  4. Making a JSOC/DRMS Module

  5. JSOC make system

  6. Web Exports via AJAX API

Developers' Weekly Progress Reports

JSOC Development Projects

  1. DSDS-Data Access from JSOC

  2. Remote DRMS/SUMS - netDRMS

JSOC Operator's Guide

  1. JSOC Administration

    JSOC Administration -- Information for management and installation of DRMS/SUMS

  2. Running Datacapture and lev0 Pipeline during SDI I&T

Database Administration

JsocWiki: JsocDevelopersGuide (last edited 2021-11-16 01:34:32 by ArtAmezcua)