Re: Add 64-bit XIDs into PostgreSQL 15
Bruce Momjian <bruce@momjian.us>
From: Bruce Momjian <bruce@momjian.us>
To: Maxim Orlov <orlovmg@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-01-06T00:02:16Z
Lists: pgsql-hackers
Commits
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API reference →
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Add SLRU tests for 64-bit page case
- a60b8a58f435 17.0 landed
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Make use FullTransactionId in 2PC filenames
- 5a1dfde8334b 17.0 landed
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Use larger segment file names for pg_notify
- 2cdf131c46e6 17.0 landed
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Index SLRUs by 64-bit integers rather than by 32-bit integers
- 4ed8f0913bfd 17.0 landed
On Thu, Dec 30, 2021 at 03:15:16PM +0300, Maxim Orlov wrote: > PFA updated working patch v6 for PG15 development cycle. > It is based on a patch by Alexander Korotkov version 5 [5] with a few fixes, > refactoring and was rebased to PG15. > > Main changes: > - Change TransactionId to 64bit > - Disk tuple format (HeapTupleHeader) is unchanged: xmin and xmax > remains 32bit > -- 32bit xid is named ShortTransactionId now. > -- Exception: see "double xmax" format below. > - Heap page format is changed to contain xid and multixact base value, > tuple's xmin and xmax are offsets from. > -- xid_base and multi_base are stored as a page special data. PageHeader > remains unmodified. > -- If after upgrade page has no free space for special data, tuples are > converted to "double xmax" format: xmin became virtual > FrozenTransactionId, xmax occupies the whole 64bit. > Page converted to new format when vacuum frees enough space. I think it is a great idea to allow the 64-XID to span the 32-bit xmin and xmax fields when needed. It would be nice if we can get focus on this feature so we are sure it gets into PG 15. Can we add this patch incrementally so people can more easily analyze it? -- Bruce Momjian <bruce@momjian.us> https://momjian.us EDB https://enterprisedb.com If only the physical world exists, free will is an illusion.