DQSegDB Transition: LIGO (CIT) → IGWN (CNAF)¶

Table of Contents¶

1. Overview
2. Background
3. What Is Changing
4. Timeline
5. Action Items for Users
6. Resources & Contacts

Overview¶

The Data Quality Segment Database (DQSegDB) is being migrated from its current home at the LIGO computing cluster at CIT to a new deployment at CNAF-CC (Bologna, Italy), operated by EGO. The new service endpoint will be https://segments.igwn.org. The full transition is targeted for July 16, 2026, ahead of IR1.

Background¶

What is DQSegDB?¶

DQSegDB stores time-based data quality (DQ) information — specifically, GPS time segments — for the LIGO, Virgo, KAGRA, and GEO interferometers. It was designed and implemented starting around 2013 to replace an earlier segment database.

Each entry is identified by a DQ flag following the pattern:

IFO:flag_name:flag_version

Example: H1:GRD-SQZ_MANAGER_OK:1

Time segments are half-closed intervals of the form [start, end). Adjacent segments can be coalesced without overlap (e.g., [0,100) + [100,500) = [0,500)).

Who Uses It?¶

DQSegDB is used by many non-low-latency workflows, including:

• Offline searches
• Summary Pages
• Omicron triggers (when low-latency frames are unavailable)
• Veto Definer Files
• User-uploaded flags and custom segment sets

What Is Changing¶

Note: HTTP-only clients will need to be updated to use HTTPS and provide a valid SciToken before the cutover.

Timeline¶

• July 14 (Tues.) - change DEFAULT_SEGMENT_SERVER variable at CIT from http://segments.ldas.cit to https://segments.ligo.org (note that LHO and LLO already have that setting), to force SciToken usage (but http and https access are both still available using the URLs)
• July 16 (Thurs.) - change official production database location from LIGO to IGWN (so new user-published segments must be done on the IGWN system)
• July 23 (Thurs.) - change DEFAULT_SEGMENT_SERVER variable to https://segments.igwn.org at LHO, LLO, and CIT (but continue to keep the LIGO system accessible)
• July 30 (Thurs.) - turn off http connections to http://segments.ldas.cit (but https://segments.ligo.org connection is still available)
• Sept. 3 (Thurs.) - turn off all connections to https://segments.ligo.org (so only https connection to IGWN is still available)

Note: Production segments meant to be stored permanently should continue to be written to https://segments.ligo.org until July 16. Starting July 16, production segments meant to be stored permanently should be written to https://segments.igwn.org.

Action Items for Users¶

• [ ] Update $DEFAULT_SEGMENT_SERVER to https://segments.igwn.org
• [ ] Ensure all clients use HTTPS (not HTTP)
• [ ] Ensure valid SciTokens are available for queries (audiences: https://segments.ligo.org or ALL)
• [ ] Test read and write operations against the IGWN instance before July 16
• [ ] Before July 16: write to both LIGO and IGWN instances in parallel if possible, on July 16 the igwn instance db entries will be overwritten by the db entries of the LIGO instance (for historical consistency) and the IGWN instance will become the new source of truth
• [ ] Verify all automated pipelines point to the new endpoint before September 3, when the LIGO instance will be turned off. Note that anything published to the LIGO instance after July 16 will be lost after September 3

Resources & Contacts¶

Contact: | Name | gitlab user |---|---| |Erin Seder| @erinelizabeth.seder | |Robert Bruntz| @robert.bruntz | |Alessio Fiori| @alessio.fiori |