From d50183c5786a21910bac566d2987f955c7bc1d62 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 3 Jun 2016 18:34:05 -0400
Subject: [PATCH] Inline the easy cases in MakeExpandedObjectReadOnly().
This attempts to buy back some of whatever performance we lost from fixing
bug #14174 by inlining the initial checks in MakeExpandedObjectReadOnly()
into the callers. We can do that in a macro without creating multiple-
evaluation hazards, so it's pretty much free notationally; and the amount
of code added to callers should be minimal as well. (Testing a value can't
take many more instructions than passing it to a subroutine.)
Might as well inline DatumIsReadWriteExpandedObject() while we're at it.
This is an ABI break for callers, so it doesn't seem safe to put into 9.5,
but I see no reason not to do it in HEAD.
---
src/backend/utils/adt/expandeddatum.c | 26 ++++----------------------
src/include/utils/expandeddatum.h | 12 ++++++++++--
2 files changed, 14 insertions(+), 24 deletions(-)
diff --git a/src/backend/utils/adt/expandeddatum.c b/src/backend/utils/adt/expandeddatum.c
index 6bb5675e083..bc30150dde9 100644
--- a/src/backend/utils/adt/expandeddatum.c
+++ b/src/backend/utils/adt/expandeddatum.c
@@ -84,36 +84,18 @@ EOH_flatten_into(ExpandedObjectHeader *eohptr,
(*eohptr->eoh_methods->flatten_into) (eohptr, result, allocated_size);
}
-/*
- * Does the Datum represent a writable expanded object?
- */
-bool
-DatumIsReadWriteExpandedObject(Datum d, bool isnull, int16 typlen)
-{
- /* Reject if it's NULL or not a varlena type */
- if (isnull || typlen != -1)
- return false;
-
- /* Reject if not a read-write expanded-object pointer */
- if (!VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(d)))
- return false;
-
- return true;
-}
-
/*
* If the Datum represents a R/W expanded object, change it to R/O.
* Otherwise return the original Datum.
+ *
+ * Caller must ensure that the datum is a non-null varlena value. Typically
+ * this is invoked via MakeExpandedObjectReadOnly(), which checks that.
*/
Datum
-MakeExpandedObjectReadOnly(Datum d, bool isnull, int16 typlen)
+MakeExpandedObjectReadOnlyInternal(Datum d)
{
ExpandedObjectHeader *eohptr;
- /* Nothing to do if it's NULL or not a varlena type */
- if (isnull || typlen != -1)
- return d;
-
/* Nothing to do if not a read-write expanded-object pointer */
if (!VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(d)))
return d;
diff --git a/src/include/utils/expandeddatum.h b/src/include/utils/expandeddatum.h
index 9c3b4667310..47989a8cf20 100644
--- a/src/include/utils/expandeddatum.h
+++ b/src/include/utils/expandeddatum.h
@@ -136,6 +136,15 @@ struct ExpandedObjectHeader
#define EOHPGetRWDatum(eohptr) PointerGetDatum((eohptr)->eoh_rw_ptr)
#define EOHPGetRODatum(eohptr) PointerGetDatum((eohptr)->eoh_ro_ptr)
+/* Does the Datum represent a writable expanded object? */
+#define DatumIsReadWriteExpandedObject(d, isnull, typlen) \
+ (((isnull) || (typlen) != -1) ? false : \
+ VARATT_IS_EXTERNAL_EXPANDED_RW(DatumGetPointer(d)))
+
+#define MakeExpandedObjectReadOnly(d, isnull, typlen) \
+ (((isnull) || (typlen) != -1) ? (d) : \
+ MakeExpandedObjectReadOnlyInternal(d))
+
extern ExpandedObjectHeader *DatumGetEOHP(Datum d);
extern void EOH_init_header(ExpandedObjectHeader *eohptr,
const ExpandedObjectMethods *methods,
@@ -143,8 +152,7 @@ extern void EOH_init_header(ExpandedObjectHeader *eohptr,
extern Size EOH_get_flat_size(ExpandedObjectHeader *eohptr);
extern void EOH_flatten_into(ExpandedObjectHeader *eohptr,
void *result, Size allocated_size);
-extern bool DatumIsReadWriteExpandedObject(Datum d, bool isnull, int16 typlen);
-extern Datum MakeExpandedObjectReadOnly(Datum d, bool isnull, int16 typlen);
+extern Datum MakeExpandedObjectReadOnlyInternal(Datum d);
extern Datum TransferExpandedObject(Datum d, MemoryContext new_parent);
extern void DeleteExpandedObject(Datum d);
--
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