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postgres_ffi: find_end_of_wal_segment: fix contrecord skipping

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Also enable corresponding test.
This commit is contained in:
Egor Suvorov
2022-05-19 03:20:06 +03:00
committed by Egor Suvorov
parent a124e44866
commit 967eb38e81
1 changed files with 31 additions and 11 deletions
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42
libs/postgres_ffi/src/xlog_utils.rs
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@@ -15,7 +15,7 @@ use crate::XLogPageHeaderData;
use crate::XLogRecord;
use crate::XLOG_PAGE_MAGIC;
use anyhow::bail;
use anyhow::{bail, ensure};
use byteorder::{ByteOrder, LittleEndian};
use bytes::BytesMut;
use bytes::{Buf, Bytes};
@@ -149,6 +149,7 @@ fn find_end_of_wal_segment(
) -> anyhow::Result<u32> {
// step back to the beginning of the page to read it in...
let mut offs: usize = start_offset - start_offset % XLOG_BLCKSZ;
let mut skipping_first_contrecord: bool = false;
let mut contlen: usize = 0;
let mut xl_crc: u32 = 0;
let mut crc: u32 = 0;
@@ -194,9 +195,21 @@ fn find_end_of_wal_segment(
);
}
if offs == 0 {
offs = XLOG_SIZE_OF_XLOG_LONG_PHD;
offs += XLOG_SIZE_OF_XLOG_LONG_PHD;
if (xlp_info & XLP_FIRST_IS_CONTRECORD) != 0 {
offs += ((xlp_rem_len + 7) & !7) as usize;
trace!(" first record is contrecord");
skipping_first_contrecord = true;
contlen = xlp_rem_len as usize;
if offs < start_offset {
// Pre-condition failed: the beginning of the segment is unexpectedly corrupted.
ensure!(start_offset - offs >= contlen,
"start_offset is in the middle of the first record (which happens to be a contrecord), \
expected to be on a record boundary. Is beginning of the segment corrupted?");
contlen = 0;
// keep skipping_first_contrecord to avoid counting the contrecord as valid, we did not check it.
}
} else {
trace!(" first record is not contrecord");
}
} else {
offs += XLOG_SIZE_OF_XLOG_SHORT_PHD;
@@ -221,12 +234,17 @@ fn find_end_of_wal_segment(
);
break; // zeros, reached the end
}
trace!(
" updating last_valid_rec_pos: 0x{:x} --> 0x{:x}",
last_valid_rec_pos,
offs
);
last_valid_rec_pos = offs;
if skipping_first_contrecord {
skipping_first_contrecord = false;
trace!(" first contrecord has been just completed");
} else {
trace!(
" updating last_valid_rec_pos: 0x{:x} --> 0x{:x}",
last_valid_rec_pos,
offs
);
last_valid_rec_pos = offs;
}
offs += 4;
rec_offs = 4;
contlen = xl_tot_len - 4;
@@ -308,7 +326,10 @@ fn find_end_of_wal_segment(
crc,
xl_crc
);
if crc == xl_crc {
if skipping_first_contrecord {
// do nothing, the flag will go down on next iteration when we're reading new record
trace!(" first conrecord has been just completed");
} else if crc == xl_crc {
// record is valid, advance the result to its end (with
// alignment to the next record taken into account)
trace!(
@@ -642,7 +663,6 @@ mod tests {
}
#[test]
#[ignore = "not yet fixed, needs correct skipping of contrecord"] // TODO
pub fn test_find_end_of_wal_crossing_segment_followed_by_small_one() {
init_logging();
test_end_of_wal(