Timesten - Sub-daemons

> Database > (TimesTen|TT) (In-Memory Database|IMDB)

1 - About

TimesTen assigns a separate subdaemons to each database to perform operations including the following tasks:

  • Manage databases.
  • Loading the database into memory from a checkpoint file on disk
  • Recovering the database if it needs to be recovered after loading it into memory
  • Performing periodic checkpoints in the background against the active database
  • Detecting and handling deadlocks. Find and break deadlocks.
  • Performing data aging. Implement the aging policies of various tables.
  • Writing log records to files. Flush the transaction log buffer to disk.
  • Rollback transactions for abnormally terminated direct-mode applications.
  • Perform required background processing for the database.

The main TimesTen daemon spawns subdaemons dynamically as they are needed.

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3 - How to

3.1 - see them

With the ttstatus utility, you get a list of:

  • the processes
  • and the sub-daemons
[[email protected] ~]$ ttstatus
TimesTen status report as of Fri Jun 22 13:08:21 2012

Daemon pid 30380 port 53396 instance tt1122
TimesTen server pid 30389 started on port 53397
------------------------------------------------------------------------
Data store /u01/app/oracle/product/aggregate_store/tt_aggr_storedi_tt_aggr_store
There are 12 connections to the data store
Shared Memory KEY 0x5b11c0df ID 993198086 (LOCKED)
PL/SQL Memory KEY 0x5c11c0df ID 993230855 Address 0x7fa0000000
Type            PID     Context             Connection Name              ConnID
Process         30449   0x00000000013b96c0  di_tt_aggr_store                  1
Subdaemon       30384   0x0000000000a4e430  Manager                        1940
Subdaemon       30384   0x0000000000aa4a70  Rollback                       1939
Subdaemon       30384   0x0000000000b88c70  Deadlock Detector              1937
Subdaemon       30384   0x0000000000b9d040  Flusher                        1938
Subdaemon       30384   0x0000000000bb1530  Checkpoint                     1936
Subdaemon       30384   0x0000000000bc5900  Aging                          1934
Subdaemon       30384   0x0000000000bd9cd0  Monitor                        1935
Subdaemon       30384   0x0000000000bee0a0  Log Marker                     1932
Subdaemon       30384   0x0000000000c02470  AsyncMV                        1931
Subdaemon       30384   0x00007fa894040c60  IndexGC                        1930
Subdaemon       30384   0x00007fa898000c20  HistGC                         1933
RAM residence policy: Always
Replication policy  : Manual
Cache Agent policy  : Manual
PL/SQL enabled.
------------------------------------------------------------------------
Accessible by group oinstall
End of report

4 - Configuration

4.1 - Minimum and Maximum Subdaemon

You can manually specify a range of subdaemons that the daemon may spawn, by specifying a minimum and maximum.

At any point in time, one subdaemon is potentially needed for TimesTen process recovery for each failed application process that is being recovered at that time.

By default, the maximum number of subdaemons is 50.

By default, TimesTen spawns a minimum of 4 subdaemons. However, you can change these settings by assigning new values to the -minsubs and -maxsubs options in the ttendaemon.options file.

5 - Documentation / Reference

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