It was discovered that in StBTofSimResParams.h (loaded in StBTofCalibMaker), a duplicated St_db_Maker was created, and it forced the DB timestamp to be xxxx1001 for each year's data. This piece of code was (only) included in the Run19 Au+Au 19.6 GeV Pi21c_SL21c production.

The duplication of St_db_Maker in any subsystem makers should be NOT allowed as it may potentially create compliations when accessing the DB entries. The fix was then submitted as git PR#145. And merged into the main branch 20210916. The SL21c library was then re-tagged and used for the productions afterwards.

The impact on the Run19 AuAu 19.6 GeV data production has been investigated.

1) Run Log comparison
Xin Dong ran DEBUG2 mode test on 19.6 GeV daq file with and without the PR#145 fix.
/gpfs01/star/pwg/dongx/BES/Run19/19.6GeV/SL21c_old/test.log    (before the change)
/gpfs01/star/pwg/dongx/BES/Run19/19.6GeV/SL21c_PR145/test.log    (after the change)
The DB timestamps for all TPC, BEMC related entries are identical.
The most concerned one are those makers after StBTofCalibMaker (ETOF, MTD and other QA/analysis makers). From the log, only the EventQAMaker log (which is after the StBTofCalibMaker) shows informative message. The timestamp from this maker shows also the desired values.
No obvious wrong DB timestamp was discovered in the log file.
But the log file shows some changes
"StBTofCalibMaker:INFO  - St_db_Maker::SetDateTime : Setting Startup Date=20181001 Time=1
St_db_Maker:DEBUG - MemoryOn
StBTofCalibMaker:INFO  - St_db_Maker::OpenMySQL : Unknown table tpc/tpcDedxPidAmpDb..tpcDedxPidAmpDb"

2) PicoDst comparison
Zaochen Ye ran several test productions over whole daq files from several different runs with and without the PR#145 fix and compared the picoDst data members directly. The comparison plots are be found here
https://www.star.bnl.gov/protected/heavy/dongx/BES/Run19/19.6GeV_PR145/plots/
No difference has been identified in the picoDst data comparison.

Based on the above two comparisons, we don't observe a direct impact on the produced picoDst data for the Run19 AuAu 19.6 GeV SL21c.