Files
scylladb/test
Lakshmi Narayanan Sreethar 3f04df55eb [Backport 6.2] replica/table: check memtable before discarding tombstone during read
On the read path, the compacting reader is applied only to the sstable
reader. This can cause an expired tombstone from an sstable to be purged
from the request before it has a chance to merge with deleted data in
the memtable leading to data resurrection.

Fix this by checking the memtables before deciding to purge tombstones
from the request on the read path. A tombstone will not be purged if a
key exists in any of the table's memtables with a minimum live timestamp
that is lower than the maximum purgeable timestamp.

Fixes #20916

`perf-simple-query` stats before and after this fix :

`build/Dev/scylla perf-simple-query --smp=1 --flush` :
```
// Before this Fix
// ---------------
94941.79 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59393 insns/op,   24029 cycles/op,        0 errors)
97551.14 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59376 insns/op,   23966 cycles/op,        0 errors)
96599.92 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59367 insns/op,   23998 cycles/op,        0 errors)
97774.91 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59370 insns/op,   23968 cycles/op,        0 errors)
97796.13 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59368 insns/op,   23947 cycles/op,        0 errors)

         throughput: mean=96932.78 standard-deviation=1215.71 median=97551.14 median-absolute-deviation=842.13 maximum=97796.13 minimum=94941.79
instructions_per_op: mean=59374.78 standard-deviation=10.78 median=59369.59 median-absolute-deviation=6.36 maximum=59393.12 minimum=59367.02
  cpu_cycles_per_op: mean=23981.67 standard-deviation=32.29 median=23967.76 median-absolute-deviation=16.33 maximum=24029.38 minimum=23947.19

// After this Fix
// --------------
95313.53 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59392 insns/op,   24058 cycles/op,        0 errors)
97311.48 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59375 insns/op,   24005 cycles/op,        0 errors)
98043.10 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59381 insns/op,   23941 cycles/op,        0 errors)
96750.31 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59396 insns/op,   24025 cycles/op,        0 errors)
93381.21 tps ( 71.1 allocs/op,   0.0 logallocs/op,  14.1 tasks/op,   59390 insns/op,   24097 cycles/op,        0 errors)

         throughput: mean=96159.93 standard-deviation=1847.88 median=96750.31 median-absolute-deviation=1151.55 maximum=98043.10 minimum=93381.21
instructions_per_op: mean=59386.60 standard-deviation=8.78 median=59389.55 median-absolute-deviation=6.02 maximum=59396.40 minimum=59374.73
  cpu_cycles_per_op: mean=24025.13 standard-deviation=58.39 median=24025.17 median-absolute-deviation=32.67 maximum=24096.66 minimum=23941.22
```

This PR fixes a regression introduced in ce96b472d3 and should be backported to older versions.

Closes scylladb/scylladb#20985

* github.com:scylladb/scylladb:
  topology-custom: add test to verify tombstone gc in read path
  replica/table: check memtable before discarding tombstone during read
  compaction_group: track maximum timestamp across all sstables

(cherry picked from commit 519e167611)

Backported from #20985 to 6.2.

Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>

Closes scylladb/scylladb#21251
2024-10-24 15:33:39 +03:00
..
2024-08-25 19:59:18 +03:00
2024-06-20 18:45:31 +03:00
2024-08-25 21:45:13 +03:00

Scylla in-source tests.

For details on how to run the tests, see docs/dev/testing.md

Shared C++ utils, libraries are in lib/, for Python - pylib/

alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cql-pytest - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool

If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).

To add a new folder, create a new directory, and then copy & edit its suite.ini.