Evgeniy, Good catch! I personally had to explain users several time why they loose data in these cases with default configuration. "AtomicConfiguration.backups = 0" and "CollectionConfiguration.backups = 0" as defaults is nonsense.
On Thu, Apr 20, 2017 at 3:27 PM, Evgeniy Stanilovskiy < estanilovs...@gridgain.com> wrote: > Guys, hope i can add one more example here. > Ones we use IgniteAtomicSequence, after topology changes some assertions > can be catched due to default AtomicConfiguration > i.e. > public static final int DFLT_BACKUPS = 0; > public static final CacheMode DFLT_CACHE_MODE = PARTITIONED; > > minimal improvements here would be to set DFLT_BACKUPS = 1; or change into > REPLICATED mode. > > thanks. > > Folks, >> >> I received a number of complaints from users that our default setting >> favor >> performance at the cost of correctness and subtle behavior. Yesterday I >> faced one such situation on my own. >> >> I started REPLICATED cache on several nodes, put some data, executed >> simple >> SQL and got wrong result. No errors, no warnings. The problem was caused >> by >> default PRIMARY_SYNC mode. WTF, our cache doesn't work out of the box! >> >> Another widely known examples are data streamer behavior, "read form >> backups" + continuous queries. >> >> I propose to change our defaults to favor *correctness* over performance, >> and create good documentation and JavaDocs to explain users how to tune >> our >> product. Proposed changes: >> >> 1) FULL_SYNC as default; >> 2) "readFromBackups=false" as default; >> 3) "IgniteDataStreamer.allowOverwrite=true" as default. >> >> Users should not think how to make Ignite work correctly. It should be >> correct out of the box. >> >> Vladimir. >> >
