[CASSANDRA-15971] full query log needs improvement

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-beta2, 4.0
• Component/s: Documentation/Website, Tool/fql
• Labels: pull-request-available
• Change Category: Quality Assurance
• Complexity: Normal
• Platform: All

Source Control Link

https://github.com/apache/cassandra/commit/3a2d709b9c782e3e2f163a46341aed073e7a6b0d

Test and Documentation Plan

https://github.com/apache/cassandra/pull/705

• Assignee: Lorina Poland
• Reporter: Jonathan Shook

Authors

Lorina Poland

Reviewers

David Capwell, Ekaterina Dimitrova

• Created: 22/Jul/20 16:34
• Updated: 03/Jan/21 17:02
• Resolved: 27/Aug/20 21:43

Description

When trying out full query logging as a possible integration for nosqlbench usage, I ran across many issues which would make it painful for users. Since there were several, they will be added to a single issue for now. This issue can be broken up if needed.

---

FQL doesn't work on my system, even though it says it is logging queries. 

With the following configuration in cassandra.yaml:

 

full_query_logging_options:
    log_dir: /REDACTED/fullquerylogs
    roll_cycle: HOURLY
    block: true
    max_queue_weight: 268435456 # 256 MiB
    max_log_size: 17179869184 # 16 GiB
    ## archive command is "/path/to/script.sh %path" where %path is replaced with the file being rolled:
    # archive_command:
    # max_archive_retries: 10

which appears to be the minimal configuration needed to enable fql, only a single file `directory-listing.cq4t` is created, which is a 64K sized file of zeroes.

 

---

Calling bin/nodetool enablefullquerylog throws an error initially.

[jshook@cass4 bin]$ ./nodetool enablefullquerylog

 

error: sun.nio.ch.FileChannelImpl.map0(int,long,long) 
-- StackTrace -- 
java.lang.NoSuchMethodException: sun.nio.ch.FileChannelImpl.map0(int,long,long) 
        at java.base/java.lang.Class.getDeclaredMethod(Class.java:2553) 
        at net.openhft.chronicle.core.OS.lambda$static$0(OS.java:51) 
        at net.openhft.chronicle.core.ClassLocal.computeValue(ClassLocal.java:53)

(full stack trace attached to this ticket)

 

Subsequent calls produce normal output:

 

[jshook@cass4 c4b1]$ bin/nodetool enablefullquerylog 
nodetool: Already logging to /home/jshook/c4b1/data/fullquerylogs 
See 'nodetool help' or 'nodetool help <command>'.

 

---

nodetool missing getfullquerylog makes it difficult to verify current fullquerylog state without changing it. The conventions for nodetool commands should be followed to avoid confusing users.

---

(maybe)

tools/bin/fqltool help

should print out help for all fqltool commands rather than simply repeating the default The most commonly used fqltool commands are..

---

https://cassandra.apache.org/doc/latest/new/fqllogging.html is malformatted, mixing the appearance of configuration with comments, which is confusing at best.

 

Issue Links

• relates to: CASSANDRA-15988 Add nodetool getfullquerylog
• relates to: CASSANDRA-16039 FQL replay should have options to ignore DDL statements