我在16G RAM的linux机器上使用Neo4j 3.2.1。 我正在尝试从11M行的csv文件加载图形，节点的最大数量约为150K节点。 它需要永远加载，我已经尝试增加堆大小，使用10000到100000的定期提交但仍然没有任何改变它现在挂了大约2个小时。 我抬头看了互联网，发现不应该花那么多时间 这是配置文件
#*****************************************************************
# Neo4j configuration
#
# For more details and a complete list of settings, please see
# https://neo4j.com/docs/operations-manual/current/reference/configuration-settings/
#*****************************************************************
# The name of the database to mount
#dbms.active_database=graph.db
# Paths of directories in the installation.
#dbms.directories.data=data
#dbms.directories.plugins=plugins
#dbms.directories.certificates=certificates
#dbms.directories.logs=logs
#dbms.directories.lib=lib
#dbms.directories.run=run
# This setting constrains all `LOAD CSV` import files to be under the `import` directory. Remove or comment it out to
# allow files to be loaded from anywhere in the filesystem; this introduces possible security problems. See the
# `LOAD CSV` section of the manual for details.
dbms.directories.import=import
# Whether requests to Neo4j are authenticated.
# To disable authentication, uncomment this line
#dbms.security.auth_enabled=false
# Enable this to be able to upgrade a store from an older version.
dbms.allow_format_migration=true
# Java Heap Size: by default the Java heap size is dynamically
# calculated based on available system resources.
# Uncomment these lines to set specific initial and maximum
# heap size.
dbms.memory.heap.initial_size=512m
dbms.memory.heap.max_size=15400m
# The amount of memory to use for mapping the store files, in bytes (or
# kilobytes with the 'k' suffix, megabytes with 'm' and gigabytes with 'g').
# If Neo4j is running on a dedicated server, then it is generally recommended
# to leave about 2-4 gigabytes for the operating system, give the JVM enough
# heap to hold all your transaction state and query context, and then leave the
# rest for the page cache.
# The default page cache memory assumes the machine is dedicated to running
# Neo4j, and is heuristically set to 50% of RAM minus the max Java heap size.
dbms.memory.pagecache.size=14g
#*****************************************************************
# Network connector configuration
#*****************************************************************
# With default configuration Neo4j only accepts local connections.
# To accept non-local connections, uncomment this line:
dbms.connectors.default_listen_address=0.0.0.0
# You can also choose a specific network interface, and configure a non-default
# port for each connector, by setting their individual listen_address.
# The address at which this server can be reached by its clients. This may be the server's IP address or DNS name, or
# it may be the address of a reverse proxy which sits in front of the server. This setting may be overridden for
# individual connectors below.
#dbms.connectors.default_advertised_address=localhost
# You can also choose a specific advertised hostname or IP address, and
# configure an advertised port for each connector, by setting their
# individual advertised_address.
# Bolt connector
dbms.connector.bolt.enabled=true
#dbms.connector.bolt.tls_level=OPTIONAL
#dbms.connector.bolt.listen_address=:7687
# HTTP Connector. There must be exactly one HTTP connector.
dbms.connector.http.enabled=true
#dbms.connector.http.listen_address=:7474
# HTTPS Connector. There can be zero or one HTTPS connectors.
dbms.connector.https.enabled=true
#dbms.connector.https.listen_address=:7473
# Number of Neo4j worker threads.
#dbms.threads.worker_count=
#*****************************************************************
# Logging configuration
#*****************************************************************
# To enable HTTP logging, uncomment this line
#dbms.logs.http.enabled=true
# Number of HTTP logs to keep.
#dbms.logs.http.rotation.keep_number=5
# Size of each HTTP log that is kept.
#dbms.logs.http.rotation.size=20m
# To enable GC Logging, uncomment this line
#dbms.logs.gc.enabled=true
# GC Logging Options
# see http://docs.oracle.com/cd/E19957-01/819-0084-10/pt_tuningjava.html#wp57013 for more information.
#dbms.logs.gc.options=-XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCApplicationStoppedTime -XX:+PrintPromotionFailure -XX:+PrintTenuringDistribution
# Number of GC logs to keep.
#dbms.logs.gc.rotation.keep_number=5
# Size of each GC log that is kept.
#dbms.logs.gc.rotation.size=20m
# Size threshold for rotation of the debug log. If set to zero then no rotation will occur. Accepts a binary suffix "k",
# "m" or "g".
#dbms.logs.debug.rotation.size=20m
# Maximum number of history files for the internal log.
#dbms.logs.debug.rotation.keep_number=7
#*****************************************************************
# Miscellaneous configuration
#*****************************************************************
# Enable this to specify a parser other than the default one.
#cypher.default_language_version=3.0
# Determines if Cypher will allow using file URLs when loading data using
# `LOAD CSV`. Setting this value to `false` will cause Neo4j to fail `LOAD CSV`
# clauses that load data from the file system.
#dbms.security.allow_csv_import_from_file_urls=true
# Retention policy for transaction logs needed to perform recovery and backups.
dbms.tx_log.rotation.retention_policy=1 days
# Enable a remote shell server which Neo4j Shell clients can log in to.
#dbms.shell.enabled=true
# The network interface IP the shell will listen on (use 0.0.0.0 for all interfaces).
#dbms.shell.host=127.0.0.1
# The port the shell will listen on, default is 1337.
#dbms.shell.port=1337
# Only allow read operations from this Neo4j instance. This mode still requires
# write access to the directory for lock purposes.
#dbms.read_only=false
# Comma separated list of JAX-RS packages containing JAX-RS resources, one
# package name for each mountpoint. The listed package names will be loaded
# under the mountpoints specified. Uncomment this line to mount the
# org.neo4j.examples.server.unmanaged.HelloWorldResource.java from
# neo4j-server-examples under /examples/unmanaged, resulting in a final URL of
# http://localhost:7474/examples/unmanaged/helloworld/{nodeId}
#dbms.unmanaged_extension_classes=org.neo4j.examples.server.unmanaged=/examples/unmanaged
#********************************************************************
# JVM Parameters
#********************************************************************
# G1GC generally strikes a good balance between throughput and tail
# latency, without too much tuning.
dbms.jvm.additional=-XX:+UseG1GC
# Have common exceptions keep producing stack traces, so they can be
# debugged regardless of how often logs are rotated.
dbms.jvm.additional=-XX:-OmitStackTraceInFastThrow
# Make sure that `initmemory` is not only allocated, but committed to
# the process, before starting the database. This reduces memory
# fragmentation, increasing the effectiveness of transparent huge
# pages. It also reduces the possibility of seeing performance drop
# due to heap-growing GC events, where a decrease in available page
# cache leads to an increase in mean IO response time.
# Try reducing the heap memory, if this flag degrades performance.
dbms.jvm.additional=-XX:+AlwaysPreTouch
# Trust that non-static final fields are really final.
# This allows more optimizations and improves overall performance.
# NOTE: Disable this if you use embedded mode, or have extensions or dependencies that may use reflection or
# serialization to change the value of final fields!
dbms.jvm.additional=-XX:+UnlockExperimentalVMOptions
dbms.jvm.additional=-XX:+TrustFinalNonStaticFields
# Disable explicit garbage collection, which is occasionally invoked by the JDK itself.
dbms.jvm.additional=-XX:+DisableExplicitGC
# Remote JMX monitoring, uncomment and adjust the following lines as needed. Absolute paths to jmx.access and
# jmx.password files are required.
# Also make sure to update the jmx.access and jmx.password files with appropriate permission roles and passwords,
# the shipped configuration contains only a read only role called 'monitor' with password 'Neo4j'.
# For more details, see: http://download.oracle.com/javase/8/docs/technotes/guides/management/agent.html
# On Unix based systems the jmx.password file needs to be owned by the user that will run the server,
# and have permissions set to 0600.
# For details on setting these file permissions on Windows see:
# http://docs.oracle.com/javase/8/docs/technotes/guides/management/security-windows.html
#dbms.jvm.additional=-Dcom.sun.management.jmxremote.port=3637
#dbms.jvm.additional=-Dcom.sun.management.jmxremote.authenticate=true
#dbms.jvm.additional=-Dcom.sun.management.jmxremote.ssl=false
#dbms.jvm.additional=-Dcom.sun.management.jmxremote.password.file=/absolute/path/to/conf/jmx.password
#dbms.jvm.additional=-Dcom.sun.management.jmxremote.access.file=/absolute/path/to/conf/jmx.access
# Some systems cannot discover host name automatically, and need this line configured:
#dbms.jvm.additional=-Djava.rmi.server.hostname=$THE_NEO4J_SERVER_HOSTNAME
# Expand Diffie Hellman (DH) key size from default 1024 to 2048 for DH-RSA cipher suites used in server TLS handshakes.
# This is to protect the server from any potential passive eavesdropping.
dbms.jvm.additional=-Djdk.tls.ephemeralDHKeySize=2048
#********************************************************************
# Wrapper Windows NT/2000/XP Service Properties
#********************************************************************
# WARNING - Do not modify any of these properties when an application
# using this configuration file has been installed as a service.
# Please uninstall the service before modifying this section. The
# service can then be reinstalled.
# Name of the service
dbms.windows_service_name=neo4j
#********************************************************************
# Other Neo4j system properties
#********************************************************************
dbms.jvm.additional=-Dunsupported.dbms.udc.source=tarball
经过长时间加载后我有这个错误
Java HotSpot(TM) 64-Bit Server VM warning: INFO: os::commit_memory(0x000000072c000000, 497025024, 0) failed; error='Ne peut allouer de l a mémoire' (errno=12)
#
# There is insufficient memory for the Java Runtime Environment to continue.
# Native memory allocation (mmap) failed to map 497025024 bytes for committing reserved memory.
我该如何解决这个问题？
查询
CREATE CONSTRAINT ON (n:Node) ASSERT n.NodeID IS UNIQUE;
USING PERIODIC COMMIT 100000
LOAD CSV WITH HEADERS FROM 'file:///file.csv'
AS line
MERGE (n1:Node {NodeID: line.p1})
MERGE (n2:Node {NodeID: line.p2})
MERGE (n1)-[:ACTING_WITH_L {Score: TOFLOAT(line.score)}]->(n2);
答案 0 :(得分：2)
当我运行查询的EXPLAIN时，我注意到那里有一个EAGER操作。当EAGER在使用LOAD CSV时是计划的一部分时，它会回退到不使用PERIODIC COMMIT的处理方式，并且会遇到内存问题。
这里有一个blog post，包括解决方案：确保节点作为单独的操作合并到图中，当您确定节点已加载时，分别处理关系与节点匹配而不是使用MERGE
不是要在两个节点中合并MERGE ... MERGE ... MERGE模式，而是使用MATCH ... MATCH ... MERGE关系。此外，如果您确定图中不存在任何关系，您可能希望在关系上使用CREATE而不是MERGE来加速它。