public inbox for [email protected]  
help / color / mirror / Atom feed
[PATCH 06/12] fixups.patch
46+ messages / 2 participants
[nested] [flat]

* [PATCH 06/12] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 3374012940..807597e648 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index ac3884b3a8..182b77a0ff 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1186,8 +1186,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--9Ek0hoCL9XbhcSqy
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="0007-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 5/7] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* [PATCH v24 05/10] fixups.patch
@ 2021-02-10 21:56  Robert Haas <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Robert Haas @ 2021-02-10 21:56 UTC (permalink / raw)

---
 doc/src/sgml/ddl.sgml                         |  3 ---
 doc/src/sgml/ref/create_table.sgml            | 15 +++++++++++----
 src/backend/access/common/detoast.c           |  5 ++---
 src/backend/access/compression/compress_lz4.c | 10 +++++-----
 src/backend/executor/nodeModifyTable.c        |  2 +-
 src/include/nodes/execnodes.h                 |  4 ++--
 6 files changed, 21 insertions(+), 18 deletions(-)

diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index 4d7ed698b9..1e9a4625cc 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -3762,9 +3762,6 @@ CREATE TABLE measurement (
        <productname>PostgreSQL</productname>
        tables (or, possibly, foreign tables).  It is possible to specify a
        tablespace and storage parameters for each partition separately.
-       By default, each column in a partition inherits the compression method
-       from parent table's column, however a different compression method can be
-       set for each partition.
       </para>
 
       <para>
diff --git a/doc/src/sgml/ref/create_table.sgml b/doc/src/sgml/ref/create_table.sgml
index 51a7a977a5..a4b297340f 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -997,10 +997,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     <term><literal>COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal></term>
     <listitem>
      <para>
-      This sets the compression method for a column.  The supported compression
-      methods are <literal>pglz</literal> and <literal>lz4</literal>.
-      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
-      was used when building <productname>PostgreSQL</productname>. The default
+      The <literal>COMPRESSION</literal> clause sets the compression method
+      for a column.  Compression is supported only for variable-width data
+      types, and is used only for columns whose storage type is main or
+      extended. (See <xref linkend="sql-altertable"/> for information on
+      column storage types.) Setting this property for a partitioned table
+      has no direct effect, because such tables have no storage of their own,
+      but the configured value is inherited by newly-created partitions.
+      The supported compression methods are <literal>pglz</literal> and
+      <literal>lz4</literal>.  <literal>lz4</literal> is available only if
+      <literal>--with-lz4</literal> was used when building
+      <productname>PostgreSQL</productname>. The default
       is <literal>pglz</literal>.
      </para>
     </listitem>
diff --git a/src/backend/access/common/detoast.c b/src/backend/access/common/detoast.c
index b78d49167b..95d5b1c12a 100644
--- a/src/backend/access/common/detoast.c
+++ b/src/backend/access/common/detoast.c
@@ -477,8 +477,8 @@ toast_get_compression_oid(struct varlena *attr)
 			return InvalidOid;
 
 		/*
-		 * Just fetch the toast compress header to know the compression method
-		 * in the compressed data.
+		 * Fetch just enough of the value to examine the compression header,
+		 * so that we can find out the compression method.
 		 */
 		attr = toast_fetch_datum_slice(attr, 0, VARHDRSZ_COMPRESS);
 	}
@@ -503,7 +503,6 @@ toast_get_compression_handler(struct varlena *attr)
 
 	cmid = TOAST_COMPRESS_METHOD(attr);
 
-	/* Get the handler routines for the compression method */
 	switch (cmid)
 	{
 		case PGLZ_COMPRESSION_ID:
diff --git a/src/backend/access/compression/compress_lz4.c b/src/backend/access/compression/compress_lz4.c
index 1856cf7df7..3079eff7eb 100644
--- a/src/backend/access/compression/compress_lz4.c
+++ b/src/backend/access/compression/compress_lz4.c
@@ -23,7 +23,7 @@
 /*
  * lz4_cmcompress - compression routine for lz4 compression method
  *
- * Compresses source into dest using the default strategy. Returns the
+ * Compresses source into dest using the LZ4 defaults. Returns the
  * compressed varlena, or NULL if compression fails.
  */
 static struct varlena *
@@ -42,8 +42,8 @@ lz4_cmcompress(const struct varlena *value)
 	valsize = VARSIZE_ANY_EXHDR(value);
 
 	/*
-	 * Get maximum size of the compressed data that lz4 compression may output
-	 * and allocate the memory for holding the compressed data and the header.
+	 * Figure out the maximum possible size of the LZ4 output, add the bytes
+	 * that will be needed for varlena overhead, and allocate that amount.
 	 */
 	max_size = LZ4_compressBound(valsize);
 	tmp = (struct varlena *) palloc(max_size + VARHDRSZ_COMPRESS);
@@ -83,10 +83,10 @@ lz4_cmdecompress(const struct varlena *value)
 	int32		rawsize;
 	struct varlena *result;
 
-	/* allocate memory for holding the uncompressed data */
+	/* allocate memory for the uncompressed data */
 	result = (struct varlena *) palloc(VARRAWSIZE_4B_C(value) + VARHDRSZ);
 
-	/* decompress data using lz4 routine */
+	/* decompress the data */
 	rawsize = LZ4_decompress_safe((char *) value + VARHDRSZ_COMPRESS,
 								  VARDATA(result),
 								  VARSIZE(value) - VARHDRSZ_COMPRESS,
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index f77deee399..920d9dd0d5 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2117,7 +2117,7 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 		TupleTableSlot *newslot = *outslot;
 
 		/*
-		 * If the called has passed an invalid slot then create a new slot.
+		 * If the caller has passed an invalid slot then create a new slot.
 		 * Otherwise, just clear the existing tuple from the slot.  This slot
 		 * should be stored by the caller so that it can be reused for
 		 * decompressing the subsequent tuples.
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 18e8ecfd90..d8483c36b3 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -1183,8 +1183,8 @@ typedef struct ModifyTableState
 	TupleTableSlot *mt_root_tuple_slot;
 
 	/*
-	 * Slot for storing the modified tuple, incase the target attribute's
-	 * compression method doesn't match with the source table.
+	 * Slot for storing the modified tuple, in case the target attribute's
+	 * compression method doesn't match that of the source table.
 	 */
 	TupleTableSlot *mt_decompress_tuple_slot;
 
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
 filename="v24-0006-alter-table-set-compression.patch"



^ permalink  raw  reply  [nested|flat] 46+ messages in thread

* Re: New Object Access Type hooks
@ 2022-03-18 14:16  Joshua Brindle <[email protected]>
  0 siblings, 0 replies; 46+ messages in thread

From: Joshua Brindle @ 2022-03-18 14:16 UTC (permalink / raw)
  To: Mark Dilger <[email protected]>; +Cc: pgsql-hackers; Robert Haas <[email protected]>; Tom Lane <[email protected]>; Andrew Dunstan <[email protected]>; Jeff Davis <[email protected]>; Joe Conway <[email protected]>; Stephen Frost <[email protected]>

On Thu, Mar 17, 2022 at 11:21 PM Mark Dilger
<[email protected]> wrote:
>
> Hackers,
>
> Over in [1], Joshua proposed a new set of Object Access Type hooks based on strings rather than Oids.
>
> His patch was written to be applied atop my patch for granting privileges on gucs.
>
> On review of his patch, I became uncomfortable with the complete lack of regression test coverage.  To be fair, he did paste a bit of testing logic to the thread, but it appears to be based on pgaudit, and it is unclear how to include such a test in the core project, where pgaudit is not assumed to be installed.
>
> First, I refactored his patch to work against HEAD and not depend on my GUCs patch.  Find that as v1-0001.  The refactoring exposed a bit of a problem.  To call the new hook for SET and ALTER SYSTEM commands, I need to pass in the Oid of a catalog table.  But since my GUC patch isn't applied yet, there isn't any such table (pg_setting_acl or whatnot) to pass.  So I'm passing InvalidOid, but I don't know if that is right.  In any event, if we want a new API like this, we should think a bit harder about whether it can be used to check operations where no table Oid is applicable.
>
> Second, I added a new test directory, src/test/modules/test_oat_hooks, which includes a new loadable module with hook implementations and a regression test for testing the object access hooks.  The main point of the test is to log which hooks get called in which order, and which hooks do or do not get called when other hooks allow or deny access.  That information shows up in the expected output as NOTICE messages.
>
> This second patch has gotten a little long, and I'd like another pair of eyes on this before spending a second day on the effort.  Please note that this is a quick WIP patch in response to the patch Joshua posted earlier today.  Sorry for sometimes missing function comments, etc.  The goal, if this design seems acceptable, is to polish this, hopefully with Joshua's assistance, and get it committed *before* my GUCs patch, so that my patch can be rebased to use it.  Otherwise, if this is rejected, I can continue on the GUC patch without this.
>

This is great, thank you for doing this. I didn't even realize the OAT
hooks had no regression tests.

It looks good to me, I reviewed both and tested the module. I wonder
if the slight abuse of subid is warranted with brand new hooks going
in but not enough to object, I just hope this doesn't rise to the too
large to merge this late level.

> (FYI, I got a test failure from src/test/recovery/t/013_crash_restart.pl when testing v1-0001.  I'm not sure yet what that is about.)
>
>
>
> [1] https://www.postgresql.org/message-id/flat/664799.1647456444%40sss.pgh.pa.us#c9721c2da88d59684ac7ac5...

>






^ permalink  raw  reply  [nested|flat] 46+ messages in thread


end of thread, other threads:[~2022-03-18 14:16 UTC | newest]

Thread overview: 46+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH 06/12] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 5/7] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2021-02-10 21:56 [PATCH v24 05/10] fixups.patch Robert Haas <[email protected]>
2022-03-18 14:16 Re: New Object Access Type hooks Joshua Brindle <[email protected]>

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox