The procedure I wrote seemed to work for Tim too, so I added a page to the wiki about it here:
> Hi Tim,
> I reproduced your problem and then managed to go through a procedure to increase the number
> of allowable open records. The following is the procedure that I used
> 1) Use odbedit to save current ODB
> save current_odb.odb
> 2) Stop all the running MIDAS processes, including mlogger and mserver using the web
> interface. Then stop mhttpd as well.
> 3) Remove your old ODB (we will recreate it after modifying MIDAS, using the backup you just
> mv .ODB.SHM .ODB.SHM.20161104
> rm /dev/shm/thomas_ODB_SHM
> 4) Make the following modifications to midas. In this particular case I have increased the
> max number of open records from 256 to 1024. You would need to change the constants if you
> want to change to other values
> diff --git a/include/midas.h b/include/midas.h
> index 02b30dd..33be7be 100644
> --- a/include/midas.h
> +++ b/include/midas.h
> @@ -254,7 +254,7 @@ typedef std::vector<std::string> STRING_LIST;
> -#define MAX_OPEN_RECORDS 256 /**< number of open DB records */
> +#define MAX_OPEN_RECORDS 1024 /**< number of open DB records */
> diff --git a/src/odb.c b/src/odb.c
> index 47ace8f..ac1bef3 100755
> --- a/src/odb.c
> +++ b/src/odb.c
> @@ -699,8 +699,8 @@ static void db_validate_sizes()
> - assert(sizeof(DATABASE_CLIENT) == 2112);
> - assert(sizeof(DATABASE_HEADER) == 135232);
> + assert(sizeof(DATABASE_CLIENT) == 8256);
> + assert(sizeof(DATABASE_HEADER) == 528448);
> The calculation is as follows (in case you want a different number of open records):
> DATABASE_CLIENT = 64 + 8*MAX_OPEN_ERCORDS = 64 + 8*1024 = 8256
> DATABASE_HEADER = 64 + 64*DATABASE_CLIENT = 64 + 64*8256 = 528448
> 5) Rebuild MIDAS
> make clean; make
> 6) Create new ODB
> odbedit -s 1000000
> Change the size of the ODB to whatever you want.
> 7) reload your original ODB
> load current_odb.odb
> 8) Rebuild your frontend against new MIDAS; then it should work and you should be able to
> produce more open records.
> 8.5*) Actually, I had a weird error where I needed to remove my .SYSTEM.SHM file as well
> when I first restarted my front-end. Not sure if that was some unrelated error, but I
> mention it here for completeness.
> This was a procedure based on something that originally was used for T2K (procedure by Renee
> Poutissou). It is possible that not all steps are necessary and that there is a better way.
> But this worked for me.
> Also, any objections from other developers to tweaking the assert checks in odb.c so that
> the values are calculated automatically and MIDAS only needs to be touched in one place to
> modify the number of open records?
> Let me know if it worked for you and I'll add these instructions to the Wiki.
> > oOne additional comment. I was able to trace the setting of the error code DB_NO_MEMORY
> > to a call to the db_add_open_record() by mserver that is initiated during the start-up
> > of my frontend via an RPC call. I checked with a debug printout that I have indeed
> > reached the number of MAX_OPEN_RECORDS
> > > Hi Midas forum,
> > >
> > > I'm having a problem with odb hotlinks after increasing sub-directories in an
> > > odb. I now get the error code DB_NO_MEMORY after some db_open_record() calls. I
> > > tried
> > >
> > > 1) increasing the parameter DEFAULT_ODB_SIZE in midas.h and make clean, make
> > > but got the same error
> > >
> > > 2) increasing the parameter MAX_OPEN_RECORDS in midas.h and make clean, make
> > > but got fatal errors from odbedit and my midas FE and couldnt run anything
> > >
> > > 3) deleting my expts SHM files and starting odbedit with "odbedit -e SLAC -s
> > > 0x1000000" to increse the odb size but got the same error?
> > >
> > > 4) I tried a different computer and got the same error code DB_NO_MEMORY
> > >
> > > Maybe I running into some system limit that restricts the humber of open records?
> > > Or maybe I've not increased the correct midas parameter?
> > >
> > > Best ,Tim.