14.03.2016 18:12, Alex Peshkoff wrote: > But use of by name search if ID is unusable due to file not > exists appears unavoidable.
Not true. Thread that is going to create file must do it while keeps db list mutex. In this case it can be sure that no other thread can try to create the file in parallel. I.e. sequence like this: 1) create dbb with flag "creating" 2) get list mutex 3) create the file and get its id 4) add the id to the list 5) release list mutex 6) acquire dbb init mutex 7) make sure that "create" flag is still here 8) continue db initialization Thread that do attach to database should do it in this sequence 1) create dbb with "init" flag 2) open the file and get id 3) get list mutex 4) if the file is already in the list, drop new dbb and use old one 5) release list mutext 6) get dbb init mutex 7) check that dbb has no "create" flag and throw "file not exist" (yes!) otherwise. 8) if dbb has "init" flag - init it, otherwise just use it. In this case there will be no thread races and clash. -- WBR, SD. ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://pubads.g.doubleclick.net/gampad/clk?id=278785231&iu=/4140 Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
