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Performance and Memory

Size the Java heap of the MetaMiner Server and Client, recognise out-of-memory symptoms, and keep disk space for the MetaMiner Database and temporary files.

MetaMiner runs several Java processes. Each has its own memory limit, set in a different place.

Process Default maximum heap Where to change it
MetaMiner Server (MMS), service metaminer Set at install time, at least 2 GB MMA Preferences > Settings > System > Memory allocation for MetaMiner's JVM
MetaQuery agent 2 GB or less, limited by physical memory MMA Preferences > Settings > MetaQuery > Memory allocation for MetaQuery agent
MetaMiner Client (MMC) 1 GB client\MetaMiner.ini
MetaMiner Administrator (MMA) 256 MB server\MetaMinerAdmin.ini
MetaMiner Web Apps, service MetaMinerWebApps 512 MB server\MetaMinerWebApps.ini

MetaMiner Server heap

Image of the MMA Settings dialog, System page, with the Java Memory Settings and Java Temp Folder groups visible

../../images/help/mma-settings-system-memory.png

  1. In the MetaMiner Administrator (MMA), open Preferences > Settings > System.
  2. Set Memory allocation for MetaMiner's JVM (in GB). The tooltip shows the largest value this machine allows.
  3. Leave Limit max memory to half of physical memory checked unless Infolytik Support advises otherwise. The operating system, the MetaMiner Database (MMDB) and the other MetaMiner processes need the rest.
  4. Click OK and restart the MetaMiner service when the MMA offers it.

The MMA writes the heap size into the Windows service definition, so the change takes effect at the next service start. Before it starts the service, the MMA checks free memory and warns "Your system's available memory is running low and is below the required amount for MMS."

TODO: add heap sizing guidance per environment size

Source to check: sizing data from support cases. Link from Sizing and Capacity once numbers are agreed.

Out-of-memory symptoms on the server

Symptom. Any of: java.lang.OutOfMemoryError in server.log or server.start.log; a java_pid<nnnn>.hprof file in the server\ folder; MMC clients disconnect together; pulls stop; the service restarts.

Cause. The heap is too small for the number of environments, objects and concurrent users, or one operation (a very large Meta Query result, a large BIAR export) needs more memory than is free.

Fix.

  1. Raise Memory allocation for MetaMiner's JVM as above, within the physical memory of the server.
  2. Restart the MetaMiner service.
  3. Move or delete old .hprof files after support has what it needs; each one is as large as the heap.

What to send support. A log bundle including the gc-*.log files, the heap setting, the server's physical memory, and the time of the error. Ask support before uploading an .hprof file; they are large.

Long pauses or high CPU on the server

Symptom. The MMS responds slowly at regular intervals; CPU is high while no pull is running.

Cause. The heap is nearly full and the Java runtime spends its time on garbage collection.

Fix. Check the latest server\logs\gc-*.log for frequent full collections, then raise the heap. Review Maximum Allowed CPUs on the same System page (default 8).

What to send support. The gc-*.log files and a log bundle.

MetaMiner Client heap

The MMC loads the metadata of every environment you open into memory. Large repositories need a larger client heap.

  1. Close the MMC.
  2. Open client\MetaMiner.ini under the installation folder in a text editor run as administrator.
  3. Change the -Xmx line at the end of the file, for example from vmarg.29=-Xmx1g to vmarg.29=-Xmx4g. Keep the vmarg numbers consecutive.
  4. Save the file and start the MMC.

Keep the value well below the free memory of the client machine. See Client System Variables.

Out-of-memory symptoms on the client

Symptom. The MMC freezes while loading environments, stays on "Processing snapshot...", or client.log shows OutOfMemoryError.

Cause. The client heap is too small for the environments selected in the Connection Manager.

Fix. Raise -Xmx in client\MetaMiner.ini, or connect to fewer environments at once.

What to send support. The client logs (File > Open MetaMiner Log Folder), the -Xmx value and the client machine's memory.

Meta Query asks before loading a large result

Symptom. Meta Query in the MMC asks for confirmation before loading a result, or refuses to load it.

Cause. The MMC asks for confirmation above 128 MB of result data and refuses above 576 MB to protect its heap.

Fix. Narrow the query (filters, fewer columns, LIMIT). Administrators can change both limits with client system variables. See Client System Variables.

What to send support. Not needed unless a small result is refused.

Disk space

Location What uses it How to manage it
server\data\mmdb\ (embedded MMDB) The MetaMiner Database Back up and monitor growth. See Embedded PostgreSQL
Java Temp Folder (default server\javatemp) Unpacked BIARs, ZIPs and downloads Change in MMA Preferences > Settings > System > Java Temp Folder; the MMA recommends 30 GB or more free
server\logs\ Logs, GC logs, heap dumps in server\ Rotated automatically; see Log Files
Backup and versions paths Web Intelligence and universe history, kept BIARs MMA Preferences > Settings > Backup; see Backup

MetaMiner notifies you when free disk space on the server's installation drive drops below MMS Disk space remaining threshold (default 20 percent), set in MMA Preferences > Settings > Notifications.

The MMDB Stability Advisor in the MMA checks the MMDB's PostgreSQL settings and database size and shows recommendations. It does not change anything. See MMDB Overview.

The MMDB or temp folder fills the disk

Symptom. The installation drive runs out of space; the MMDB or the service stops; the disk space notification arrives.

Cause. MMDB growth from history and audit data, large exports kept on disk, or a temp folder on a small drive.

Fix.

  1. Move the Java Temp Folder to a drive with space (MMA System page), then restart the service.
  2. Check whether Keep BIAR Files (MMA Pull page) and Keep Web Intelligence versions? (MMA Backup page) are needed.
  3. Free space or extend the drive before you restart the MMDB.

What to send support. Disk usage per folder under the installation folder and a log bundle.

Next steps