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* [PATCH v24 09/10] new compression method extension for zlib
@ 2020-10-16 14:26 dilipkumar <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: dilipkumar @ 2020-10-16 14:26 UTC (permalink / raw)
Dilip Kumar
---
contrib/Makefile | 1 +
contrib/cmzlib/.gitignore | 4 +
contrib/cmzlib/Makefile | 26 +++++
contrib/cmzlib/cmzlib--1.0.sql | 13 +++
contrib/cmzlib/cmzlib.c | 157 +++++++++++++++++++++++++++++
contrib/cmzlib/cmzlib.control | 5 +
contrib/cmzlib/expected/cmzlib.out | 53 ++++++++++
contrib/cmzlib/sql/cmzlib.sql | 22 ++++
8 files changed, 281 insertions(+)
create mode 100644 contrib/cmzlib/.gitignore
create mode 100644 contrib/cmzlib/Makefile
create mode 100644 contrib/cmzlib/cmzlib--1.0.sql
create mode 100644 contrib/cmzlib/cmzlib.c
create mode 100644 contrib/cmzlib/cmzlib.control
create mode 100644 contrib/cmzlib/expected/cmzlib.out
create mode 100644 contrib/cmzlib/sql/cmzlib.sql
diff --git a/contrib/Makefile b/contrib/Makefile
index f27e458482..9e452d8dd0 100644
--- a/contrib/Makefile
+++ b/contrib/Makefile
@@ -12,6 +12,7 @@ SUBDIRS = \
bloom \
btree_gin \
btree_gist \
+ cmzlib \
citext \
cube \
dblink \
diff --git a/contrib/cmzlib/.gitignore b/contrib/cmzlib/.gitignore
new file mode 100644
index 0000000000..5dcb3ff972
--- /dev/null
+++ b/contrib/cmzlib/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/contrib/cmzlib/Makefile b/contrib/cmzlib/Makefile
new file mode 100644
index 0000000000..956fbe7cc8
--- /dev/null
+++ b/contrib/cmzlib/Makefile
@@ -0,0 +1,26 @@
+# contrib/cmzlib/Makefile
+
+MODULE_big = cmzlib
+OBJS = \
+ $(WIN32RES) \
+ cmzlib.o
+
+EXTENSION = cmzlib
+DATA = cmzlib--1.0.sql
+PGFILEDESC = "zlib compression method "
+
+SHLIB_LINK += $(filter -lz, $(LIBS))
+
+REGRESS = cmzlib
+
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/cmzlib
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/contrib/cmzlib/cmzlib--1.0.sql b/contrib/cmzlib/cmzlib--1.0.sql
new file mode 100644
index 0000000000..41f2f95870
--- /dev/null
+++ b/contrib/cmzlib/cmzlib--1.0.sql
@@ -0,0 +1,13 @@
+/* contrib/cm_lz4/cmzlib--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION cmzlib" to load this file. \quit
+
+CREATE FUNCTION zlibhandler(internal)
+RETURNS compression_am_handler
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
+
+-- Compression method
+CREATE ACCESS METHOD zlib TYPE COMPRESSION HANDLER zlibhandler;
+COMMENT ON ACCESS METHOD zlib IS 'zlib compression method';
diff --git a/contrib/cmzlib/cmzlib.c b/contrib/cmzlib/cmzlib.c
new file mode 100644
index 0000000000..686a7c7e0d
--- /dev/null
+++ b/contrib/cmzlib/cmzlib.c
@@ -0,0 +1,157 @@
+/*-------------------------------------------------------------------------
+ *
+ * cmzlib.c
+ * zlib compression method
+ *
+ * Copyright (c) 2015-2018, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ * contrib/cmzlib/cmzlib.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+#include "access/compressamapi.h"
+#include "access/toast_internals.h"
+
+#include "fmgr.h"
+#include "utils/builtins.h"
+
+#include <zlib.h>
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(zlibhandler);
+
+void _PG_init(void);
+
+/*
+ * Module initialize function: initialize info about zlib
+ */
+void
+_PG_init(void)
+{
+
+}
+
+#define ZLIB_MAX_DICTIONARY_LENGTH 32768
+#define ZLIB_DICTIONARY_DELIM (" ,")
+
+typedef struct
+{
+ int level;
+ Bytef dict[ZLIB_MAX_DICTIONARY_LENGTH];
+ unsigned int dictlen;
+} zlib_state;
+
+/*
+ * zlib_cmcompress - compression routine for zlib compression method
+ *
+ * Compresses source into dest using the default compression level.
+ * Returns the compressed varlena, or NULL if compression fails.
+ */
+static struct varlena *
+zlib_cmcompress(const struct varlena *value, int32 header_size)
+{
+ int32 valsize,
+ len;
+ struct varlena *tmp = NULL;
+ z_streamp zp;
+ int res;
+ zlib_state state;
+
+ state.level = Z_DEFAULT_COMPRESSION;
+
+ zp = (z_streamp) palloc(sizeof(z_stream));
+ zp->zalloc = Z_NULL;
+ zp->zfree = Z_NULL;
+ zp->opaque = Z_NULL;
+
+ if (deflateInit(zp, state.level) != Z_OK)
+ elog(ERROR, "could not initialize compression library: %s", zp->msg);
+
+ valsize = VARSIZE_ANY_EXHDR(DatumGetPointer(value));
+ tmp = (struct varlena *) palloc(valsize + header_size);
+ zp->next_in = (void *) VARDATA_ANY(value);
+ zp->avail_in = valsize;
+ zp->avail_out = valsize;
+ zp->next_out = (void *) ((char *) tmp + header_size);
+
+ do
+ {
+ res = deflate(zp, Z_FINISH);
+ if (res == Z_STREAM_ERROR)
+ elog(ERROR, "could not compress data: %s", zp->msg);
+ } while (zp->avail_in != 0);
+
+ Assert(res == Z_STREAM_END);
+
+ len = valsize - zp->avail_out;
+ if (deflateEnd(zp) != Z_OK)
+ elog(ERROR, "could not close compression stream: %s", zp->msg);
+ pfree(zp);
+
+ if (len > 0)
+ {
+ SET_VARSIZE_COMPRESSED(tmp, len + header_size);
+ return tmp;
+ }
+
+ pfree(tmp);
+ return NULL;
+}
+
+/*
+ * zlib_cmdecompress - decompression routine for zlib compression method
+ *
+ * Returns the decompressed varlena.
+ */
+static struct varlena *
+zlib_cmdecompress(const struct varlena *value, int32 header_size)
+{
+ struct varlena *result;
+ z_streamp zp;
+ int res = Z_OK;
+
+ zp = (z_streamp) palloc(sizeof(z_stream));
+ zp->zalloc = Z_NULL;
+ zp->zfree = Z_NULL;
+ zp->opaque = Z_NULL;
+
+ if (inflateInit(zp) != Z_OK)
+ elog(ERROR, "could not initialize compression library: %s", zp->msg);
+
+ zp->next_in = (void *) ((char *) value + header_size);
+ zp->avail_in = VARSIZE(value) - header_size;
+ zp->avail_out = VARRAWSIZE_4B_C(value);
+
+ result = (struct varlena *) palloc(zp->avail_out + VARHDRSZ);
+ SET_VARSIZE(result, zp->avail_out + VARHDRSZ);
+ zp->next_out = (void *) VARDATA(result);
+
+ while (zp->avail_in > 0)
+ {
+ res = inflate(zp, 0);
+ if (!(res == Z_OK || res == Z_STREAM_END))
+ elog(ERROR, "could not uncompress data: %s", zp->msg);
+ }
+
+ if (inflateEnd(zp) != Z_OK)
+ elog(ERROR, "could not close compression library: %s", zp->msg);
+
+ pfree(zp);
+ return result;
+}
+
+const CompressionAmRoutine zlib_compress_methods = {
+ .type = T_CompressionAmRoutine,
+ .datum_compress = zlib_cmcompress,
+ .datum_decompress = zlib_cmdecompress,
+ .datum_decompress_slice = NULL};
+
+Datum
+zlibhandler(PG_FUNCTION_ARGS)
+{
+ PG_RETURN_POINTER(&zlib_compress_methods);
+}
diff --git a/contrib/cmzlib/cmzlib.control b/contrib/cmzlib/cmzlib.control
new file mode 100644
index 0000000000..2eb10f3a83
--- /dev/null
+++ b/contrib/cmzlib/cmzlib.control
@@ -0,0 +1,5 @@
+# cm_lz4 extension
+comment = 'cmzlib compression method'
+default_version = '1.0'
+module_pathname = '$libdir/cmzlib'
+relocatable = true
diff --git a/contrib/cmzlib/expected/cmzlib.out b/contrib/cmzlib/expected/cmzlib.out
new file mode 100644
index 0000000000..2b6fac7e0b
--- /dev/null
+++ b/contrib/cmzlib/expected/cmzlib.out
@@ -0,0 +1,53 @@
+CREATE EXTENSION cmzlib;
+-- zlib compression
+CREATE TABLE zlibtest(f1 TEXT COMPRESSION pglz);
+INSERT INTO zlibtest VALUES(repeat('1234567890',1004));
+INSERT INTO zlibtest VALUES(repeat('1234567890 one two three',1004));
+SELECT length(f1) FROM zlibtest;
+ length
+--------
+ 10040
+ 24096
+(2 rows)
+
+-- alter compression method with rewrite
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION pglz;
+\d+ zlibtest
+ Table "public.zlibtest"
+ Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1 | text | | | | extended | pglz | |
+
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION zlib;
+\d+ zlibtest
+ Table "public.zlibtest"
+ Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1 | text | | | | extended | zlib | |
+
+-- preserve old compression method
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION pglz PRESERVE (zlib);
+INSERT INTO zlibtest VALUES (repeat('1234567890',1004));
+\d+ zlibtest
+ Table "public.zlibtest"
+ Column | Type | Collation | Nullable | Default | Storage | Compression | Stats target | Description
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1 | text | | | | extended | pglz | |
+
+SELECT pg_column_compression(f1) FROM zlibtest;
+ pg_column_compression
+-----------------------
+ zlib
+ zlib
+ pglz
+(3 rows)
+
+SELECT length(f1) FROM zlibtest;
+ length
+--------
+ 10040
+ 24096
+ 10040
+(3 rows)
+
+DROP TABLE zlibtest;
diff --git a/contrib/cmzlib/sql/cmzlib.sql b/contrib/cmzlib/sql/cmzlib.sql
new file mode 100644
index 0000000000..ea8d206625
--- /dev/null
+++ b/contrib/cmzlib/sql/cmzlib.sql
@@ -0,0 +1,22 @@
+CREATE EXTENSION cmzlib;
+
+-- zlib compression
+CREATE TABLE zlibtest(f1 TEXT COMPRESSION pglz);
+INSERT INTO zlibtest VALUES(repeat('1234567890',1004));
+INSERT INTO zlibtest VALUES(repeat('1234567890 one two three',1004));
+SELECT length(f1) FROM zlibtest;
+
+-- alter compression method with rewrite
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION pglz;
+\d+ zlibtest
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION zlib;
+\d+ zlibtest
+
+-- preserve old compression method
+ALTER TABLE zlibtest ALTER COLUMN f1 SET COMPRESSION pglz PRESERVE (zlib);
+INSERT INTO zlibtest VALUES (repeat('1234567890',1004));
+\d+ zlibtest
+SELECT pg_column_compression(f1) FROM zlibtest;
+SELECT length(f1) FROM zlibtest;
+
+DROP TABLE zlibtest;
--
2.17.0
--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v24-0010-Support-compression-methods-options.patch"
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: [DOC] Introducing Quick Start Guide to PL/pgSQL and PL/Python Documentation
@ 2023-12-19 15:48 Peter Eisentraut <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: Peter Eisentraut @ 2023-12-19 15:48 UTC (permalink / raw)
To: Ishaan Adarsh <[email protected]>; [email protected]
On 16.12.23 11:49, Ishaan Adarsh wrote:
> 1. Added a new section titled "Quick Start Guide" to both PL/pgSQL and
> PL/Python documentation.
> 2. Included step-by-step instructions for users to get started with
> these procedural languages.
> 3. Provided explanations, code snippets, and examples to illustrate key
> concepts.
The way I read it, that's not really what your patch does. Your patch
explains how to write an extension in PL/pgSQL and PL/Python,
respectively. Which is okay, I guess, but a bit unusual. But I
wouldn't call that an unqualified "quick start" in the respective
languages. Also, it seems to repeat the very basics of setting up an
extension file structure etc. repeatedly in each chapter.
The existing documentation has "explanations, code snippets, and
examples". Are they not good? Do you have more? Better ones? Why are
yours separate from the existing ones?
I think it would be useful to take a step back here and define the
purpose of a bit clearer.
^ permalink raw reply [nested|flat] 2+ messages in thread
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2020-10-16 14:26 [PATCH v24 09/10] new compression method extension for zlib dilipkumar <[email protected]>
2023-12-19 15:48 Re: [DOC] Introducing Quick Start Guide to PL/pgSQL and PL/Python Documentation Peter Eisentraut <[email protected]>
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