mirror of
https://github.com/neondatabase/neon.git
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55a4cf64a1
Introduce the concept of a "ZenithWalRecord", which can be a Postgres WAL record that is replayed with the Postgres WAL redo process, or a built-in type that is handled entirely by pageserver code. Replace the special code to replay Postgres XACT commit/abort records with new Zenith WAL records. A separate zenith WAL record is created for each modified CLOG page. This allows removing the 'main_data_offset' field from stored PostgreSQL WAL records, which saves some memory and some disk space in delta layers. Introduce zenith WAL records for updating bits in the visibility map. Previously, when e.g. a heap insert cleared the VM bit, we duplicated the heap insert WAL record for the affected VM page. That was very wasteful. The heap WAL record could be massive, containing a full page image in the worst case. This addresses github issue #941.
40 lines
1.1 KiB
Rust
40 lines
1.1 KiB
Rust
#![allow(non_upper_case_globals)]
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#![allow(non_camel_case_types)]
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#![allow(non_snake_case)]
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// bindgen creates some unsafe code with no doc comments.
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#![allow(clippy::missing_safety_doc)]
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// suppress warnings on rust 1.53 due to bindgen unit tests.
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// https://github.com/rust-lang/rust-bindgen/issues/1651
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#![allow(deref_nullptr)]
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use serde::{Deserialize, Serialize};
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include!(concat!(env!("OUT_DIR"), "/bindings.rs"));
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pub mod controlfile_utils;
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pub mod nonrelfile_utils;
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pub mod pg_constants;
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pub mod relfile_utils;
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pub mod waldecoder;
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pub mod xlog_utils;
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// See TransactionIdIsNormal in transam.h
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pub const fn transaction_id_is_normal(id: TransactionId) -> bool {
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id > pg_constants::FIRST_NORMAL_TRANSACTION_ID
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}
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// See TransactionIdPrecedes in transam.c
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pub const fn transaction_id_precedes(id1: TransactionId, id2: TransactionId) -> bool {
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/*
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* If either ID is a permanent XID then we can just do unsigned
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* comparison. If both are normal, do a modulo-2^32 comparison.
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*/
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if !(transaction_id_is_normal(id1)) || !transaction_id_is_normal(id2) {
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return id1 < id2;
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}
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let diff = id1.wrapping_sub(id2) as i32;
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diff < 0
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}
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