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Posted to commits@cassandra.apache.org by "Brandon Williams (Jira)" <ji...@apache.org> on 2022/11/29 13:00:00 UTC
[jira] [Updated] (CASSANDRA-18078) Consider removing MAXWRITETIME function
[ https://issues.apache.org/jira/browse/CASSANDRA-18078?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Brandon Williams updated CASSANDRA-18078:
-----------------------------------------
Description:
CASSANDRA-17425 added a new {{MAXWRITETIME}} function that allows to retrieve the maximum timestamp of a multi-cell column. For example:
{code:java}
> CREATE TABLE t (k int PRIMARY KEY, v set<int>);
> INSERT INTO t (k, v) VALUES (1, {1, 2}) USING TIMESTAMP 100;
> UPDATE t USING TIMESTAMP 200 SET v += {3} WHERE k=1;
> SELECT maxwritetime(v) FROM t;
maxwritetime(v)
-----------------
200
{code}
Later, CASSANDRA-8877 added the means to retrieve the write times and TTLs of each of the cells in a multi-cell column:
{code:java}
> SELECT writetime(v) FROM t;
writetime(v)
-----------------
[100, 100, 200]
> SELECT writetime(v[1]) FROM t;
writetime(v[1])
-----------------
100
{code}
Quite recently, CASSANDRA-18060 has added generic CQL functions to get the min and max items in a collection. Those functions can be used in combination with the classic {{writetime}} function to get the same results as the new {{maxwritetime}} function:
{code:java}
> SELECT collection_max(writetime(v)) FROM t;
system.collection_max(writetime(v))
-------------------------------------
200
{code}
Those new functions can also be used to get the min timestamp, or the min/max TTL, for which there isn't a specific function:
{code:java}
SELECT collection_min(writetime(v)) FROM t;
SELECT collection_min(writetime(v)) FROM t;
SELECT collection_avg(writetime(v)) FROM t;
SELECT collection_min(ttl(v)) FROM t;
SELECT collection_min(ttl(v)) FROM t;
SELECT collection_avg(ttl(v)) FROM t;
{code}
I think this makes the new {{maxwritetime}} mostly redundant, since the new functions can achieve the same results in a more generic way. Since the new {{maxwritetime}} function is only on trunk, we should consider whether we want to remove it in favour of the generic functions.
was:
CASSANDRA-17456 added a new {{MAXWRITETIME}} function that allows to retrieve the maximum timestamp of a multi-cell column. For example:
{code:java}
> CREATE TABLE t (k int PRIMARY KEY, v set<int>);
> INSERT INTO t (k, v) VALUES (1, {1, 2}) USING TIMESTAMP 100;
> UPDATE t USING TIMESTAMP 200 SET v += {3} WHERE k=1;
> SELECT maxwritetime(v) FROM t;
maxwritetime(v)
-----------------
200
{code}
Later, CASSANDRA-8877 added the means to retrieve the write times and TTLs of each of the cells in a multi-cell column:
{code:java}
> SELECT writetime(v) FROM t;
writetime(v)
-----------------
[100, 100, 200]
> SELECT writetime(v[1]) FROM t;
writetime(v[1])
-----------------
100
{code}
Quite recently, CASSANDRA-18060 has added generic CQL functions to get the min and max items in a collection. Those functions can be used in combination with the classic {{writetime}} function to get the same results as the new {{maxwritetime}} function:
{code:java}
> SELECT collection_max(writetime(v)) FROM t;
system.collection_max(writetime(v))
-------------------------------------
200
{code}
Those new functions can also be used to get the min timestamp, or the min/max TTL, for which there isn't a specific function:
{code:java}
SELECT collection_min(writetime(v)) FROM t;
SELECT collection_min(writetime(v)) FROM t;
SELECT collection_avg(writetime(v)) FROM t;
SELECT collection_min(ttl(v)) FROM t;
SELECT collection_min(ttl(v)) FROM t;
SELECT collection_avg(ttl(v)) FROM t;
{code}
I think this makes the new {{maxwritetime}} mostly redundant, since the new functions can achieve the same results in a more generic way. Since the new {{maxwritetime}} function is only on trunk, we should consider whether we want to remove it in favour of the generic functions.
> Consider removing MAXWRITETIME function
> ---------------------------------------
>
> Key: CASSANDRA-18078
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18078
> Project: Cassandra
> Issue Type: Improvement
> Components: CQL/Syntax
> Reporter: Andres de la Peña
> Priority: Normal
> Time Spent: 10m
> Remaining Estimate: 0h
>
> CASSANDRA-17425 added a new {{MAXWRITETIME}} function that allows to retrieve the maximum timestamp of a multi-cell column. For example:
> {code:java}
> > CREATE TABLE t (k int PRIMARY KEY, v set<int>);
> > INSERT INTO t (k, v) VALUES (1, {1, 2}) USING TIMESTAMP 100;
> > UPDATE t USING TIMESTAMP 200 SET v += {3} WHERE k=1;
> > SELECT maxwritetime(v) FROM t;
> maxwritetime(v)
> -----------------
> 200
> {code}
> Later, CASSANDRA-8877 added the means to retrieve the write times and TTLs of each of the cells in a multi-cell column:
> {code:java}
> > SELECT writetime(v) FROM t;
> writetime(v)
> -----------------
> [100, 100, 200]
> > SELECT writetime(v[1]) FROM t;
> writetime(v[1])
> -----------------
> 100
> {code}
> Quite recently, CASSANDRA-18060 has added generic CQL functions to get the min and max items in a collection. Those functions can be used in combination with the classic {{writetime}} function to get the same results as the new {{maxwritetime}} function:
> {code:java}
> > SELECT collection_max(writetime(v)) FROM t;
> system.collection_max(writetime(v))
> -------------------------------------
> 200
> {code}
> Those new functions can also be used to get the min timestamp, or the min/max TTL, for which there isn't a specific function:
> {code:java}
> SELECT collection_min(writetime(v)) FROM t;
> SELECT collection_min(writetime(v)) FROM t;
> SELECT collection_avg(writetime(v)) FROM t;
> SELECT collection_min(ttl(v)) FROM t;
> SELECT collection_min(ttl(v)) FROM t;
> SELECT collection_avg(ttl(v)) FROM t;
> {code}
> I think this makes the new {{maxwritetime}} mostly redundant, since the new functions can achieve the same results in a more generic way. Since the new {{maxwritetime}} function is only on trunk, we should consider whether we want to remove it in favour of the generic functions.
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