v4-0002-Refactor-pg_waldump-Separate-logic-used-to-calcul.patch
application/x-patch
Filename: v4-0002-Refactor-pg_waldump-Separate-logic-used-to-calcul.patch
Type: application/x-patch
Part: 1
Patch
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Format: format-patch
Series: patch v4-0002
Subject: Refactor: pg_waldump: Separate logic used to calculate the required read size.
| File | + | − |
|---|---|---|
| src/bin/pg_waldump/pg_waldump.c | 26 | 13 |
From 9f719d5744c293a91aca5a933b357296180281ff Mon Sep 17 00:00:00 2001
From: Amul Sul <sulamul@gmail.com>
Date: Thu, 26 Jun 2025 11:42:53 +0530
Subject: [PATCH v4 2/8] Refactor: pg_waldump: Separate logic used to calculate
the required read size.
This refactoring prepares the codebase for an upcoming patch that will
support reading WAL from tar files. The logic for calculating the
required read size has been updated to handle both normal WAL files
and WAL files located inside a tar archive.
---
src/bin/pg_waldump/pg_waldump.c | 39 ++++++++++++++++++++++-----------
1 file changed, 26 insertions(+), 13 deletions(-)
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index a49b2fd96c7..8d0cd9e7156 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -326,6 +326,29 @@ identify_target_directory(char *directory, char *fname)
return NULL; /* not reached */
}
+/* Returns the size in bytes of the data to be read. */
+static inline int
+required_read_len(XLogDumpPrivate *private, XLogRecPtr targetPagePtr,
+ int reqLen)
+{
+ int count = XLOG_BLCKSZ;
+
+ if (private->endptr != InvalidXLogRecPtr)
+ {
+ if (targetPagePtr + XLOG_BLCKSZ <= private->endptr)
+ count = XLOG_BLCKSZ;
+ else if (targetPagePtr + reqLen <= private->endptr)
+ count = private->endptr - targetPagePtr;
+ else
+ {
+ private->endptr_reached = true;
+ return -1;
+ }
+ }
+
+ return count;
+}
+
/* pg_waldump's XLogReaderRoutine->segment_open callback */
static void
WALDumpOpenSegment(XLogReaderState *state, XLogSegNo nextSegNo,
@@ -383,21 +406,11 @@ WALDumpReadPage(XLogReaderState *state, XLogRecPtr targetPagePtr, int reqLen,
XLogRecPtr targetPtr, char *readBuff)
{
XLogDumpPrivate *private = state->private_data;
- int count = XLOG_BLCKSZ;
+ int count = required_read_len(private, targetPagePtr, reqLen);
WALReadError errinfo;
- if (private->endptr != InvalidXLogRecPtr)
- {
- if (targetPagePtr + XLOG_BLCKSZ <= private->endptr)
- count = XLOG_BLCKSZ;
- else if (targetPagePtr + reqLen <= private->endptr)
- count = private->endptr - targetPagePtr;
- else
- {
- private->endptr_reached = true;
- return -1;
- }
- }
+ if (private->endptr_reached)
+ return -1;
if (!WALRead(state, readBuff, targetPagePtr, count, private->timeline,
&errinfo))
--
2.47.1