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Jacob Salomon asked whether release 15 removes the roughly 2-billion-page chunk size limit and the rows-per-page limit, which would need page header and slot table changes. Art Kagel said the answers wait for the v15 feature release because of NDA. Gabor Fekete pointed to an earlier presentation on new rowid and page address formats; Jacob found it covered slot table and header changes.
Auto-generated by Claude from the posts below — may be imperfect; read the full thread.
Jacob Salomon — source: IBM Community (ConnectedCommunity.org) Informix forum
Hi Family.
I just finished watching the seminar on release 15. Surprisingly short; Carlton usually manages to fill in the full hour. Also, I could not see where where typed questions were being answered. But all that aside:
One question I posted... Well, a bit of a preface:
Before the "large page size" feature of release 10, the page header included a 24-bit page number (offset within the chunk) with page flags filling the remaining 8 bits of a 32-bit. word. Hence, a chunk is limited to ~ 16 million pages at 2K/page. (OK 4K/page on AIX)
With the large page size feature, the page number is now 32 bits, the flags have been moved to another location in the page header. To my surprise the page number/offset is still measured in 2K pages. (I learned this by dumping pages from a 16K-page DBspace.) Still, it limits the chunk size limit to an insane ~2-billion pages (at 2K each). (That's insane in a
good
way. :-)
When Carlton said all limits have been effectively removed I asked: Does this include the 2-billion page limit on the size of a chunk? And if that limit has indeed been removed, that size would no longer fit into the [signed] 32-bit word in the page header. Does that mean the layout of the page header will need to be modified?
Similarly, Carlton seemed to imply that the rows-per-page limit would also be removed (or at lease raised), though I'm not certain I heard that correctly. This implies a modification of the layout of the slot table that we have known and loved (or at least tolerated :-) since release 4.0.
Rather than email Carlton alone (he's busy enough, I think) I decided to air my questions to all of us.
All in the interest of science...
------------------------------
Jacob Salomon
---
Nobody goes there anymore, it's too crowded. --Attr: Yogi Berra
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↪ replying to Jacob Salomon
Art Kagel — source: IBM Community (ConnectedCommunity.org) Informix forum
Jacob:
So you missed Carlton's response to your question about the page headers. His answer was basically "Wait for the detailed feature update when v15 is released."
Those of us who know the answers to your questions are under NDA, so you won't get answers any sooner than that.
Art
------------------------------
Art S. Kagel, President and Principal Consultant
ASK Database Management Corp.
www.askdbmgt.com
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↪ replying to Jacob Salomon
Gábor Fekete — source: IBM Community (ConnectedCommunity.org) Informix forum
Hi
9 month earlier was Scott Picket presentation about the New version. He mentioned the new rowid format and pages address format. If I can guess correctly they will use some 64 bit address sizes format. This will allow to reach the OS storage limit as todays was mentioned
https://youtu.be/SMAmPGJ3KCw?si=y9zgfI7-th2dle9p
------------------------------
Gábor Fekete
Software Engineer
Capital Systems
Budapest
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↪ replying to Gábor Fekete
Jacob Salomon — source: IBM Community (ConnectedCommunity.org) Informix forum
Thank you Gabor.
I had actually missed that presentation so thank you for pointing me to it.
The information I was looking for is discussed starting about 6 minutes in, at slide 6 through 13 minutes at slide 12. And I see they *are* contemplating a change in the slot table as part of changing the rows per page as well as rowid format. And I'm pretty sure it will require a change in the format of the page header, that 24 bytes ain't gonna cut it no more.
Nice to know that my guesses were basically correct,
sans
some detail.
+----- Jacob Salomon --------------------------------------------------+
| The first lesson of economics is scarcity: there is never enough of |
| anything to fully satisfy all those who want it. The first lesson of |
| politics is to disregard the first lesson of economics. |
+--------------- Thomas Sowell (Is Reality Optional?::Student Loans) --+
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