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gus bjorklund
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> On Apr 19, 2017, at 4:12 PM, George Potemkin wrote: > > MTX latch was a first latch in Progress db and it was called db lock. > > > wrong. sorry george. you get a red card. 
the first release to have shared memory was 5.2A. In that release, there were two memory locks: the DB lock and the MTX lock. The MTX lock served a purpose similar to what it does today although the implementation was quite different. For various reasons, /all/ database writes were performed while holding the MTX lock. The DB lock was used to lock the entire shared memory region when any shared data structure was accessed or modified. Some other fun facts about the ancient version 5: * max segment size was 8 MB, * max -B was 32,000, * db and bi block size was 1 kb, * lock table size was limited to 32 kb, * bi cluster size was fixed at 16 kb. * TP1 benchmark performance was about 10 tps. * no data servers * 4GL could connect to only one database at a time * there were no internal procedures in 4GL -gus
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the first release to have shared memory was 5.2A. In that release, there were two memory locks: the DB lock and the MTX lock. The MTX lock served a purpose similar to what it does today although the implementation was quite different. For various reasons, /all/ database writes were performed while holding the MTX lock. The DB lock was used to lock the entire shared memory region when any shared data structure was accessed or modified. Some other fun facts about the ancient version 5: * max segment size was 8 MB, * max -B was 32,000, * db and bi block size was 1 kb, * lock table size was limited to 32 kb, * bi cluster size was fixed at 16 kb. * TP1 benchmark performance was about 10 tps. * no data servers * 4GL could connect to only one database at a time * there were no internal procedures in 4GL -gusContinue reading...