Uniqueness is determined by the partition key PLUS the clustering columns. Hard
to tell from your data below, but is it possible that one of the clustering
columns (perhaps g) has different values? That would easily explain the 2 rows
returned – because they ARE different rows in the same partition. In your data
model, make sure you need all the clustering columns to determine uniqueness or
you will indeed have more rows than you might expect.
Sean Durity
From: Ahmed Eljami <ahmed.elj...@gmail.com>
Sent: Wednesday, May 15, 2019 10:56 AM
To: user@cassandra.apache.org
Subject: [EXTERNAL] Two separate rows for the same partition !!
Hi guys,
We have a strange problem with the data in cassandra, after inserting twice the
same partition with differents columns, we see that cassandra returns 2 rows on
cqlsh rather than one...:
a| b| c| d| f| g| h| i| j| k| l
----------------------------------+----------------+-----------+----------------------+---------------+-----------------------------+--------+-----------+------------------------------------------------------------------------------+--------+--------
dddd| bbb| rrr| tttt| Token | abcd| | False |
{'expiration': '1557943260838', 'fname': 'WS', 'freshness': '1556299239910'} |
null | null
dddd| bbb| rrr| tttt| Token | abcd| | null |
null |
| null
With the primary key = PRIMARY KEY ((a, b, c), d, e, f, g)
On the sstable we have the following data:
[
{
"partition" : {
"key" : [ "dddd", "bbb", "rrr" ],
"position" : 3760
},
"rows" : [
{
"type" : "range_tombstone_bound",
"start" : {
"type" : "inclusive",
"clustering" : [ "tttt", "Token", "abcd", "*" ],
"deletion_info" : { "marked_deleted" : "2019-04-26T17:20:39.909Z",
"local_delete_time" : "2019-04-26T17:20:39Z" }
}
},
{
"type" : "range_tombstone_bound",
"end" : {
"type" : "exclusive",
"clustering" : [ "tttt", "Token", "abcd", "" ],
"deletion_info" : { "marked_deleted" : "2019-04-26T17:20:39.909Z",
"local_delete_time" : "2019-04-26T17:20:39Z" }
}
},
{
"type" : "row",
"position" : 3974,
"clustering" : [ "tttt", "Token", "abcd", "" ],
"liveness_info" : { "tstamp" : "2019-04-26T17:20:39.910Z", "ttl" :
31708792, "expires_at" : "2020-04-27T17:20:31Z", "expired" : false },
"cells" : [
{ "name" : "connected", "value" : false },
{ "name" : "dattrib", "deletion_info" : { "marked_deleted" :
"2019-04-26T17:20:39.909999Z", "local_delete_time" : "2019-04-26T17:20:39Z" } },
{ "name" : "dattrib", "path" : [ "expiration" ], "value" :
"1557943260838" },
{ "name" : "dattrib", "path" : [ "fname" ], "value" : "WS" },
{ "name" : "dattrib", "path" : [ "freshness" ], "value" :
"1556299239910" }
]
},
{
"type" : "row",
"position" : 4123,
"clustering" : [ "tttt", "Token", "abcd", "" ],
"cells" : [
{ "name" : "dvalue", "value" : "", "tstamp" :
"2019-04-26T17:20:39.910Z", "ttl" : 31708792, "expires_at" :
"2020-04-27T17:20:31Z", "expired" : false }
]
},
{
"type" : "range_tombstone_bound",
"start" : {
"type" : "exclusive",
"clustering" : [ "tttt", "Token", "abcd", "" ],
"deletion_info" : { "marked_deleted" : "2019-04-26T17:20:39.909Z",
"local_delete_time" : "2019-04-26T17:20:39Z" }
}
},
{
"type" : "range_tombstone_bound",
"end" : {
"type" : "inclusive",
"clustering" : [ "tttt", "Token", "abcd", "*" ],
"deletion_info" : { "marked_deleted" : "2019-04-26T17:20:39.909Z",
"local_delete_time" : "2019-04-26T17:20:39Z" }
}
}
]
}
what's weired that the two rows with "position" : 3974, and "position" : 4123
should be on the same row...!!
Since, we can't reproduce the issue ...
Any idea please ?
Thanks.
--
Cordialement;
Ahmed ELJAMI
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