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Martin Hope
JIST
Asked: 2025-04-21 05:04:48 +0800 CST
  • 7

我想在 ScyllaDB 中定义压缩的限制，但我在scylla.yaml文件中没有看到这个设置。我只在文件中看到了 Apache Cassandra 的这个选项cassandra.yaml，请参阅设置：

# Throttles compaction to the given total throughput across the entire
# system. The faster you insert data, the faster you need to compact in
# order to keep the sstable count down, but in general, setting this to
# 16 to 32 times the rate you are inserting data is more than sufficient.
# Setting this to 0 disables throttling. Note that this accounts for all types
# of compaction, including validation compaction (building Merkle trees
# for repairs).
compaction_throughput: 64MiB/s

如何定义 ScyllaDB（免费版）中的压缩限制？

cassandra
Martin Hope
JIST
Asked: 2024-09-25 16:08:43 +0800 CST
  • 7

我尝试根据 Cassandra 查询语言 (CQL) 识别引擎（Cassandra、Scylla、AstraDB、CosmosDB、Yugabyte 等）。我专注于表system.local和system.peers，请参阅示例：

SELECT release_version FROM system.local;

和

SELECT release_version FROM system.peers;

但我没有得到有关系统/引擎的相关信息。你解决了这个问题吗？

cassandra
Martin Hope
JIST
Asked: 2023-10-04 17:10:00 +0800 CST
  • 6

我使用标准“cassandra-driver”来访问 Cassandra 和 Scylla，以便通过 BatchStatement 插入/更新数据。我通过批量 500 行进行更新，并且仅针对 Cassandra 出现此错误（对于 Scylla 一切正常）：

Error from server: code=2200 [Invalid query] message="Batch too large"

Python代码参见：

from cassandra import ConsistencyLevel
from cassandra.cluster import Cluster
from cassandra.cluster import ExecutionProfile
from cassandra.cluster import EXEC_PROFILE_DEFAULT
from cassandra.query import BatchStatement

...
cluster = Cluster(contact_points=["localhost"],
                  port=9042,
                  execution_profiles={EXEC_PROFILE_DEFAULT: profile},
                  control_connection_timeout=60,
                  idle_heartbeat_interval=60,
                  connect_timeout=60)
session = cluster.connect(keyspace="catalog")
...
insert_statement = session.prepare(f"INSERT INTO rn6.t01 ({columns}) VALUES ({items})")
batch = BatchStatement(consistency_level=ConsistencyLevel.ONE)

data_frm = pandas.DataFrame(generator.integers(999999, 
                size=(run_setup.bulk_row, run_setup.bulk_col)),
                columns=[f"fn{i}" for i in range(run_setup.bulk_col)])

# prepare data
for row in data_frm.values:
    batch.add(insert_statement, row)

session.execute(batch)

Cassandra 和 Scylla 似乎对批处理语句有不同的默认限制。这些限制你知道吗？

python