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https://issues.apache.org/jira/browse/CASSANDRA-6572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13986591#comment-13986591
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Benedict commented on CASSANDRA-6572:
-------------------------------------
Some comments on the in progress patch:
* Don't create a string with the header and convert it to bytes - convert the
string to bytes and write a normal byte-encoded header with timestamp + length
as a long. This will make encoding the prepared statement parameters much
easier also
* Encapsulate queryQue and logPosition into a single object, and use an
atomicinteger for the position - don't synchronise, just bump the position
however much you need, then write to the owned range. On flush swap the object
(use an AtomicReference to track the current buffer)
* On flush, append directly from the byte buffer, don't copy it. Create a
FileOutputStream and call its appropriate write method with the range that is
in use
* On the read path, you're now eagerly reading _all_ files which is likely to
blow up the heap; at least create an Iterator that only reads a whole file at
once (preferably read a chunk of a file at a time, with a BufferedInputStream)
* On replay timing we want to target hitting the same delta from epoch for
running the query, not the delta from the prior query - this should help
prevent massive timing drifts
* Query frequency can be an int rather than an Integer to avoid unboxing
* I think it would be nice if we checked the actual CFMetaData for the
keyspaces we're modifying in the CQLStatement, rather than doing a find within
the whole string, but it's not too big a deal
* atomicCounterLock needs to be removed
* As a general rule, never copy array contents with a loop - always use
System.arraycopy
* Still need to log the thread + query id as Jonathan mentioned
> Workload recording / playback
> -----------------------------
>
> Key: CASSANDRA-6572
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6572
> Project: Cassandra
> Issue Type: New Feature
> Components: Core, Tools
> Reporter: Jonathan Ellis
> Assignee: Lyuben Todorov
> Fix For: 2.1.1
>
> Attachments: 6572-trunk.diff
>
>
> "Write sample mode" gets us part way to testing new versions against a real
> world workload, but we need an easy way to test the query side as well.
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