Hi experts,
I have a (near) real-time application in which inserts into the database needs
to be visible to queries from other threads with minimal delay. The inserts are
triggered by real-time events and are therefore asynchronous (i.e. many
performance tips I read related to batch inserts or copy do not apply here,
since these events cannot be predicted or batched), and the inserted data need
to be available within a couple of seconds to other threads (for example, an
inserted row that only appears to other query threads 5 seconds or more after
the insert is not acceptable). The delay should be under 2 seconds maximum,
sub-1 second would be great.
My questions are: (1) Does the MVCC architecture introduce significant delays
between insert by a thread and visibility by other threads (I am unclear about
how multiple versions are "collapsed" or reconciled, as well as how different
query threads are seeing which version)? (2) Are there any available benchmarks
that can measure this delay? (3) What are relevant config parameters that will
reduce this delay?
Thanks for your patience with my ignorance of MVCC (still learning more about
it),
Steve
