Re: 6.0 Shared Memory Usage
At 05:24 PM 6/13/95 +0000, james@bi-tech.com wrote:
}Apologies if this have been covered before but:
}
}On NCR (4.3) using Online 6.00.UE1G6, we started Online, ran one of
}our maintentance jobs (which takes about 8-10 hours), and now shared
}memory usage is now up to the 290 MB mark, and climbing.
A feature of the new "Dynamic" Server Architecture.
}Other than an occasional dbaccess, no other process is using Informix.
}
}Assuming that we aren't doing anything _stupid_, is this normal
}behavior for 6.0+? I understand from the book Informix-OnLine
}Performance Tuning that:
}
}"Once these segments have been allocated, they cannot be de-allocated
}except by bringing down the OnLine system. Note, however, that
}shared memory pages are treated like any other memory. They can be
}paged out if real memory is needed for any other purpose."
This is correct with version 6. In version 7.1, the ability to drop free'd
segments becomes available.
}Does this mean I need to configure a googaplex of swap space? Is
}this reasonable behavior (for Informix)?
There are (I believe there also in ver. 6) $ONCONFIG parameters to control
the amount memory that OnLine can consume. If these are not set (in
particular SHMTOTAL), then SHM will grow until there's no more room to grow
- potentially.
}We have experienced the same behavior during a benchmark on
}HP-UX (w 7.1) where shared-memory usage approached 1GB.
}(Luckily we had 2 GB in the box, and 3 GB of swap, so no problem, 8:) )
Check your documentation with the version 7.1 product. You CAN control the
amount of memory consumed by OnLine. You also now, under this version, have
the ability to drop free'd segments.
Jon
}
}Comments?
}--
}**-------------------------+---------------------------**
}|James Bennett | Phone: 916.891.5281 |
}|Bi-Tech Software, Inc | Fax : 916.891.5011 |
}|1072 Marauder, Suite A | EMail: james@bi-tech.com |
}|Chico, CA 95926 | "If it was easy, anyone |
}| | could do it." |
}**-------------------------+---------------------------**
}
}
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Jon Vemo Internet: jvemo@cyberspace.com
Bothell, WA USA
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