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https://issues.apache.org/jira/browse/CASSANDRA-19018?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17814134#comment-17814134
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Caleb Rackliffe edited comment on CASSANDRA-19018 at 2/6/24 4:48 PM:
---------------------------------------------------------------------
To make the "short read" problem above more concrete, here's a pretty easy
repro:
{noformat}
@Test
public void testPartialUpdatesWithShortRead()
{
CLUSTER.schemaChange(withKeyspace("CREATE TABLE %s.partial_updates (k int
PRIMARY KEY, a int, b int) WITH read_repair = 'NONE'"));
CLUSTER.schemaChange(withKeyspace("CREATE INDEX ON %s.partial_updates(a)
USING 'sai'"));
CLUSTER.schemaChange(withKeyspace("CREATE INDEX ON %s.partial_updates(b)
USING 'sai'"));
SAIUtil.waitForIndexQueryable(CLUSTER, KEYSPACE);
// insert a split row
CLUSTER.get(1).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a) VALUES (0, 1) USING TIMESTAMP 1"));
CLUSTER.get(2).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, b) VALUES (0, 2) USING TIMESTAMP 2"));
// insert a split row that only matches on non-strict filtering but is
kicked out by RFP
CLUSTER.get(1).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a, b) VALUES (1, 4, 2) USING TIMESTAMP 3"));
CLUSTER.get(2).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a, b) VALUES (1, 1, 4) USING TIMESTAMP 4"));
String select = withKeyspace("SELECT * FROM %s.partial_updates WHERE a = 1
AND b = 2");
Iterator<Object[]> initialRows =
CLUSTER.coordinator(1).executeWithPaging(select, ConsistencyLevel.ALL, 1);
assertRows(initialRows, row(0, 1, 2));
}
{noformat}
This fails the same way if you bump the page size to 2 and set a {{LIMIT 1}}.
was (Author: maedhroz):
To make the "short read" problem above more concrete, here's a pretty easy
repro:
{noformat}
@Test
public void testPartialUpdatesWithShortRead()
{
CLUSTER.schemaChange(withKeyspace("CREATE TABLE %s.partial_updates (k int
PRIMARY KEY, a int, b int) WITH read_repair = 'NONE'"));
CLUSTER.schemaChange(withKeyspace("CREATE INDEX ON %s.partial_updates(a)
USING 'sai'"));
CLUSTER.schemaChange(withKeyspace("CREATE INDEX ON %s.partial_updates(b)
USING 'sai'"));
SAIUtil.waitForIndexQueryable(CLUSTER, KEYSPACE);
// insert a split row
CLUSTER.get(1).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a) VALUES (0, 1) USING TIMESTAMP 1"));
CLUSTER.get(2).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, b) VALUES (0, 2) USING TIMESTAMP 2"));
// insert a split row that only matches on non-strict filtering but is
kicked out by RFP
CLUSTER.get(1).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a, b) VALUES (1, 4, 2) USING TIMESTAMP 3"));
CLUSTER.get(2).executeInternal(withKeyspace("INSERT INTO
%s.partial_updates(k, a, b) VALUES (1, 1, 4) USING TIMESTAMP 4"));
String select = withKeyspace("SELECT * FROM %s.partial_updates WHERE a = 1
AND b = 2");
Iterator<Object[]> initialRows =
CLUSTER.coordinator(1).executeWithPaging(select, ConsistencyLevel.ALL, 1);
assertRows(initialRows, row(0, 1, 2));
}
{noformat}
This fails the same way if you bump the page size to 2 and set a {{LIMIT 1}}.
[~adelapena] Something like
https://github.com/apache/cassandra/pull/3044/commits/8d701c4f67bd7670fa1968fe4540259e4145000e#diff-d8fb4ccd5cc47d7e0043f473bee725932acd5cc9a9ac2721eb96dabcecca3515R272
seems to fix this, but I'm not sure if it's correct overall.
> An SAI-specific mechanism to ensure consistency isn't violated for
> multi-column (i.e. AND) queries at CL > ONE
> --------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-19018
> URL: https://issues.apache.org/jira/browse/CASSANDRA-19018
> Project: Cassandra
> Issue Type: Bug
> Components: Consistency/Coordination, Feature/SAI
> Reporter: Caleb Rackliffe
> Assignee: Caleb Rackliffe
> Priority: Normal
> Fix For: 5.0-rc, 5.x
>
> Attachments: ci_summary-1.html, ci_summary.html,
> result_details.tar-1.gz, result_details.tar.gz
>
> Time Spent: 8h 50m
> Remaining Estimate: 0h
>
> CASSANDRA-19007 is going to be where we add a guardrail around
> filtering/index queries that use intersection/AND over partially updated
> non-key columns. (ex. Restricting one clustering column and one normal column
> does not cause a consistency problem, as primary keys cannot be partially
> updated.) This issue exists to attempt to fix this specifically for SAI in
> 5.0.x, as Accord will (last I checked) not be available until the 5.1 release.
> The SAI-specific version of the originally reported issue is this:
> {noformat}
> try (Cluster cluster = init(Cluster.build(2).withConfig(config ->
> config.with(GOSSIP).with(NETWORK)).start()))
> {
> cluster.schemaChange(withKeyspace("CREATE TABLE %s.t (k int
> PRIMARY KEY, a int, b int)"));
> cluster.schemaChange(withKeyspace("CREATE INDEX ON %s.t(a) USING
> 'sai'"));
> cluster.schemaChange(withKeyspace("CREATE INDEX ON %s.t(b) USING
> 'sai'"));
> // insert a split row
> cluster.get(1).executeInternal(withKeyspace("INSERT INTO %s.t(k,
> a) VALUES (0, 1)"));
> cluster.get(2).executeInternal(withKeyspace("INSERT INTO %s.t(k,
> b) VALUES (0, 2)"));
> // Uncomment this line and test succeeds w/ partial writes
> completed...
> //cluster.get(1).nodetoolResult("repair",
> KEYSPACE).asserts().success();
> String select = withKeyspace("SELECT * FROM %s.t WHERE a = 1 AND
> b = 2");
> Object[][] initialRows = cluster.coordinator(1).execute(select,
> ConsistencyLevel.ALL);
> assertRows(initialRows, row(0, 1, 2)); // not found!!
> }
> {noformat}
> To make a long story short, the local SAI indexes are hiding local partial
> matches from the coordinator that would combine there to form full matches.
> Simple non-index filtering queries also suffer from this problem, but they
> hide the partial matches in a different way. I'll outline a possible solution
> for this in the comments that takes advantage of replica filtering protection
> and the repaired/unrepaired datasets...and attempts to minimize the amount of
> extra row data sent to the coordinator.
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