[
https://issues.apache.org/jira/browse/CASSANDRA-21699?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Michael Semb Wever updated CASSANDRA-21699:
-------------------------------------------
Description:
{{InMemoryTrie}} reads {{cassandra.memtable.row_overhead_size}} for its
allocated size threshold:
{code:java}
int limitInMB = CassandraRelevantProperties.MEMTABLE_OVERHEAD_SIZE.getInt(2048
* 10 / 11);
if (limitInMB < 1 || limitInMB > 2047)
throw new AssertionError(...);
{code}
That property is a byte count that {{SkipListMemtable}} reads for its per-row
overhead, and the trie reads the same value as a megabyte count, so one
property drives two unrelated settings. An operator who tunes the row overhead
moves the trie threshold as well, and a row overhead above 2047 makes the class
initialiser throw an {{AssertionError}}.
{{SimulationRunner}} shows the effect in the tree: it sets the property to 100
for the row overhead, which cuts the trie threshold from 1861MB to 100MB, so a
simulated trie memtable reports that it reached its limit after a twentieth of
the memory the default allows.
{{CassandraRelevantProperties}} already declares {{MEMTABLE_TRIE_SIZE_LIMIT}}
({{cassandra.trie_size_limit_mb}}), and no code reads it. The patch reads that
property instead, and names it in the range message. The default threshold does
not change. The static block becomes a package-private method, so a test can
read the threshold more than once.
Patch:
[mck/CASSANDRA-21699/5.0|https://github.com/thelastpickle/cassandra/tree/mck/CASSANDRA-21699/5.0]
Provenance:
[eb272c8458|https://github.com/datastax/cassandra/commit/eb272c8458390d6e3bbbb557c62cf68b9967f04c]
by [~mike_tr_adamson]. That commit makes the same property change and also
lowers the default threshold to 1GB, which this patch leaves out, because the
default belongs to a separate discussion. That commit carries no test; this
patch adds one.
was:
{{InMemoryTrie}} reads {{cassandra.memtable.row_overhead_size}} for its
allocated size threshold:
{code:java}
int limitInMB = CassandraRelevantProperties.MEMTABLE_OVERHEAD_SIZE.getInt(2048
* 10 / 11);
if (limitInMB < 1 || limitInMB > 2047)
throw new AssertionError(...);
{code}
That property is a byte count that {{SkipListMemtable}} reads for its per-row
overhead, and the trie reads the same value as a megabyte count, so one
property drives two unrelated settings. An operator who tunes the row overhead
moves the trie threshold as well, and a row overhead above 2047 makes the class
initialiser throw an {{AssertionError}}.
{{SimulationRunner}} shows the effect in the tree: it sets the property to 100
for the row overhead, which cuts the trie threshold from 1861MB to 100MB, so a
simulated trie memtable reports that it reached its limit after a twentieth of
the memory the default allows.
{{CassandraRelevantProperties}} already declares {{MEMTABLE_TRIE_SIZE_LIMIT}}
({{cassandra.trie_size_limit_mb}}), and no code reads it. The patch reads that
property instead, and names it in the range message. The default threshold does
not change. The static block becomes a package-private method, so a test can
read the threshold more than once.
Patch:
[mck/upstream/trie-size-limit-property/5.0|https://github.com/thelastpickle/cassandra/tree/mck/upstream/trie-size-limit-property/5.0]
Provenance:
[eb272c8458|https://github.com/datastax/cassandra/commit/eb272c8458390d6e3bbbb557c62cf68b9967f04c]
by [~mike_tr_adamson]. That commit makes the same property change and also
lowers the default threshold to 1GB, which this patch leaves out, because the
default belongs to a separate discussion. That commit carries no test; this
patch adds one.
> InMemoryTrie reads the row overhead property for its size limit
> ---------------------------------------------------------------
>
> Key: CASSANDRA-21699
> URL: https://issues.apache.org/jira/browse/CASSANDRA-21699
> Project: Apache Cassandra
> Issue Type: Bug
> Components: Local/Memtable
> Reporter: Michael Semb Wever
> Priority: Normal
> Fix For: 5.0.x, 6.0.x, 7.x
>
>
> {{InMemoryTrie}} reads {{cassandra.memtable.row_overhead_size}} for its
> allocated size threshold:
> {code:java}
> int limitInMB =
> CassandraRelevantProperties.MEMTABLE_OVERHEAD_SIZE.getInt(2048 * 10 / 11);
> if (limitInMB < 1 || limitInMB > 2047)
> throw new AssertionError(...);
> {code}
> That property is a byte count that {{SkipListMemtable}} reads for its per-row
> overhead, and the trie reads the same value as a megabyte count, so one
> property drives two unrelated settings. An operator who tunes the row
> overhead moves the trie threshold as well, and a row overhead above 2047
> makes the class initialiser throw an {{AssertionError}}.
> {{SimulationRunner}} shows the effect in the tree: it sets the property to
> 100 for the row overhead, which cuts the trie threshold from 1861MB to 100MB,
> so a simulated trie memtable reports that it reached its limit after a
> twentieth of the memory the default allows.
> {{CassandraRelevantProperties}} already declares {{MEMTABLE_TRIE_SIZE_LIMIT}}
> ({{cassandra.trie_size_limit_mb}}), and no code reads it. The patch reads
> that property instead, and names it in the range message. The default
> threshold does not change. The static block becomes a package-private method,
> so a test can read the threshold more than once.
> Patch:
> [mck/CASSANDRA-21699/5.0|https://github.com/thelastpickle/cassandra/tree/mck/CASSANDRA-21699/5.0]
> Provenance:
> [eb272c8458|https://github.com/datastax/cassandra/commit/eb272c8458390d6e3bbbb557c62cf68b9967f04c]
> by [~mike_tr_adamson]. That commit makes the same property change and also
> lowers the default threshold to 1GB, which this patch leaves out, because the
> default belongs to a separate discussion. That commit carries no test; this
> patch adds one.
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