On 2021-Jun-04, Tom Lane wrote:
> Alvaro Herrera <alvhe...@alvh.no-ip.org> writes:
> > Now, while this patch does seem to work correctly, it raises a number of
> > weird cpluspluscheck warnings, which I think are attributable to the
> > new macro definitions. I didn't look into it closely, but I suppose it
> > should be fixable given sufficient effort:
>
> Didn't test, but the first one is certainly fixable by adding a cast,
> and I guess the others might be as well.
I get no warnings with this one. I'm a bit wary of leaving
VARDATA_COMPRESSED_GET_EXTSIZE unchanged, but at least nothing in this
patch requires a cast there.
--
Álvaro Herrera Valdivia, Chile
>From d1a0b624e316dcd50aabaf21c4ab4de19b15b604 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvhe...@alvh.no-ip.org>
Date: Fri, 4 Jun 2021 19:09:30 -0400
Subject: [PATCH v2] Reduce overhead of TOAST recompression on table rewrite
---
src/backend/access/common/toast_compression.c | 30 ---------------
src/include/access/toast_compression.h | 37 ++++++++++++++++++-
src/include/postgres.h | 6 +--
3 files changed, 39 insertions(+), 34 deletions(-)
diff --git a/src/backend/access/common/toast_compression.c b/src/backend/access/common/toast_compression.c
index 9e9d4457ac..38688e7cfc 100644
--- a/src/backend/access/common/toast_compression.c
+++ b/src/backend/access/common/toast_compression.c
@@ -247,36 +247,6 @@ lz4_decompress_datum_slice(const struct varlena *value, int32 slicelength)
#endif
}
-/*
- * Extract compression ID from a varlena.
- *
- * Returns TOAST_INVALID_COMPRESSION_ID if the varlena is not compressed.
- */
-ToastCompressionId
-toast_get_compression_id(struct varlena *attr)
-{
- ToastCompressionId cmid = TOAST_INVALID_COMPRESSION_ID;
-
- /*
- * If it is stored externally then fetch the compression method id from
- * the external toast pointer. If compressed inline, fetch it from the
- * toast compression header.
- */
- if (VARATT_IS_EXTERNAL_ONDISK(attr))
- {
- struct varatt_external toast_pointer;
-
- VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
-
- if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
- cmid = VARATT_EXTERNAL_GET_COMPRESS_METHOD(toast_pointer);
- }
- else if (VARATT_IS_COMPRESSED(attr))
- cmid = VARDATA_COMPRESSED_GET_COMPRESS_METHOD(attr);
-
- return cmid;
-}
-
/*
* CompressionNameToMethod - Get compression method from compression name
*
diff --git a/src/include/access/toast_compression.h b/src/include/access/toast_compression.h
index 9e2c1cbe1a..8756de77d8 100644
--- a/src/include/access/toast_compression.h
+++ b/src/include/access/toast_compression.h
@@ -13,6 +13,8 @@
#ifndef TOAST_COMPRESSION_H
#define TOAST_COMPRESSION_H
+#include "access/detoast.h"
+
/*
* GUC support.
*
@@ -78,8 +80,41 @@ extern struct varlena *lz4_decompress_datum_slice(const struct varlena *value,
int32 slicelength);
/* other stuff */
-extern ToastCompressionId toast_get_compression_id(struct varlena *attr);
extern char CompressionNameToMethod(const char *compression);
extern const char *GetCompressionMethodName(char method);
+
+/*
+ * Extract compression ID from a varlena.
+ *
+ * Returns TOAST_INVALID_COMPRESSION_ID if the varlena is not compressed.
+ */
+static inline ToastCompressionId
+toast_get_compression_id(struct varlena *attr)
+{
+ ToastCompressionId cmid = TOAST_INVALID_COMPRESSION_ID;
+
+ /*
+ * If it is stored externally then fetch the compression method id from
+ * the external toast pointer. If compressed inline, fetch it from the
+ * toast compression header.
+ */
+ if (VARATT_IS_EXTERNAL_ONDISK(attr))
+ {
+ struct varatt_external toast_pointer;
+
+ VARATT_EXTERNAL_GET_POINTER(toast_pointer, attr);
+
+ if (VARATT_EXTERNAL_IS_COMPRESSED(toast_pointer))
+ cmid = VARATT_EXTERNAL_GET_COMPRESS_METHOD(toast_pointer);
+ }
+ else if (VARATT_IS_COMPRESSED(attr))
+ cmid = VARDATA_COMPRESSED_GET_COMPRESS_METHOD(attr);
+
+ return cmid;
+}
+
+
+
+
#endif /* TOAST_COMPRESSION_H */
diff --git a/src/include/postgres.h b/src/include/postgres.h
index 8e02f91108..7437f4dcf3 100644
--- a/src/include/postgres.h
+++ b/src/include/postgres.h
@@ -365,13 +365,13 @@ typedef struct
#define VARDATA_COMPRESSED_GET_EXTSIZE(PTR) \
(((varattrib_4b *) (PTR))->va_compressed.va_tcinfo & VARLENA_EXTSIZE_MASK)
#define VARDATA_COMPRESSED_GET_COMPRESS_METHOD(PTR) \
- (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo >> VARLENA_EXTSIZE_BITS)
+ ((ToastCompressionId) (((varattrib_4b *) (PTR))->va_compressed.va_tcinfo >> VARLENA_EXTSIZE_BITS))
/* Same, when working directly with a struct varatt_external */
#define VARATT_EXTERNAL_GET_EXTSIZE(toast_pointer) \
- ((toast_pointer).va_extinfo & VARLENA_EXTSIZE_MASK)
+ ((int32) ((toast_pointer).va_extinfo & VARLENA_EXTSIZE_MASK))
#define VARATT_EXTERNAL_GET_COMPRESS_METHOD(toast_pointer) \
- ((toast_pointer).va_extinfo >> VARLENA_EXTSIZE_BITS)
+ ((ToastCompressionId) ((toast_pointer).va_extinfo >> VARLENA_EXTSIZE_BITS))
#define VARATT_EXTERNAL_SET_SIZE_AND_COMPRESS_METHOD(toast_pointer, len, cm) \
do { \
--
2.20.1
