On 20 July 2017 at 19:09, Ashutosh Sharma <ashu.coe...@gmail.com> wrote:
> I had a quick look into this patch and also tested it and following
> are my observations.
>
> 1) I am seeing a server crash when passing any non meaningful value
> for t_infomask2 to heap_infomask_flags().
>
> postgres=# SELECT heap_infomask_flags(2816, 3);
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
> !> \q
>
> Following is the backtrace,
>
> (gdb) bt
> #0 0x0000000000d9c55b in pg_detoast_datum (datum=0x0) at fmgr.c:1833
> #1 0x0000000000b87374 in construct_md_array (elems=0x2ad74c0,
> nulls=0x0, ndims=1, dims=0x7ffc0b0bbcd0, lbs=0x7ffc0b0bbcc0,
> elmtype=25, elmlen=-1,
> elmbyval=0 '\000', elmalign=105 'i') at arrayfuncs.c:3382
> #2 0x0000000000b8709f in construct_array (elems=0x2ad74c0, nelems=10,
> elmtype=25, elmlen=-1, elmbyval=0 '\000', elmalign=105 'i') at
> arrayfuncs.c:3316
> #3 0x00007fb8001603a5 in heap_infomask_flags (fcinfo=0x2ad3b88) at
> heapfuncs.c:597
>
Fixed.
> 2) I can see the documentation for heap_infomask(). But, I do not see
> it being defined or used anywhere in the patch.
>
> + <para>
> + The <function>heap_infomask</function> function can be used to
> unpack the
> + recognised bits of the infomasks of heap tuples.
> + </para>
>
Fixed. Renamed the function, missed a spot.
> 3) If show_combined flag is set to it's default value and a tuple is
> frozen then may i know the reason for not showing it as frozen tuple
> when t_infomask2
> is passed as zero.
It was a consequence of (1). Fixed.
> 4) I think, it would be better to use the same argument name for the
> newly added function i.e heap_infomask_flags() in both documentation
> and sql file. I am basically refering to 'include_combined' argument.
> IF you see the function definition, the argument name used is
> 'include_combined' whereas in documentation you have mentioned
> 'show_combined'.
>
Fixed, thanks.
I want to find time to expand the tests on this some more and look more
closely, but here it is for now.
--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
From a25c1e50e3b3ff493a018ab594a71dc3d64832ee Mon Sep 17 00:00:00 2001
From: Craig Ringer <cr...@2ndquadrant.com>
Date: Thu, 20 Jul 2017 11:20:21 +0800
Subject: [PATCH v2] Introduce heap_infomask_flags to decode infomask and
infomask2
---
contrib/pageinspect/Makefile | 3 +-
contrib/pageinspect/expected/page.out | 85 ++++++++++++++++++
contrib/pageinspect/heapfuncs.c | 120 ++++++++++++++++++++++++++
contrib/pageinspect/pageinspect--1.6--1.7.sql | 9 ++
contrib/pageinspect/pageinspect.control | 2 +-
contrib/pageinspect/sql/page.sql | 24 ++++++
doc/src/sgml/pageinspect.sgml | 32 +++++++
7 files changed, 273 insertions(+), 2 deletions(-)
create mode 100644 contrib/pageinspect/pageinspect--1.6--1.7.sql
diff --git a/contrib/pageinspect/Makefile b/contrib/pageinspect/Makefile
index 0a3cbee..de114c7 100644
--- a/contrib/pageinspect/Makefile
+++ b/contrib/pageinspect/Makefile
@@ -5,7 +5,8 @@ OBJS = rawpage.o heapfuncs.o btreefuncs.o fsmfuncs.o \
brinfuncs.o ginfuncs.o hashfuncs.o $(WIN32RES)
EXTENSION = pageinspect
-DATA = pageinspect--1.5.sql pageinspect--1.5--1.6.sql \
+DATA = pageinspect--1.6--1.7.sql \
+ pageinspect--1.5.sql pageinspect--1.5--1.6.sql \
pageinspect--1.4--1.5.sql pageinspect--1.3--1.4.sql \
pageinspect--1.2--1.3.sql pageinspect--1.1--1.2.sql \
pageinspect--1.0--1.1.sql pageinspect--unpackaged--1.0.sql
diff --git a/contrib/pageinspect/expected/page.out b/contrib/pageinspect/expected/page.out
index 8e15947..b335265 100644
--- a/contrib/pageinspect/expected/page.out
+++ b/contrib/pageinspect/expected/page.out
@@ -82,6 +82,91 @@ SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
(1 row)
+-- If we freeze the only tuple on test1, the infomask should
+-- always be the same in all test runs.
+VACUUM FREEZE test1;
+SELECT t_infomask, t_infomask2, flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+ LATERAL heap_infomask_flags(t_infomask, t_infomask2, true) m(flags);
+ t_infomask | t_infomask2 | flags
+------------+-------------+----------------------------------------------------------------------------
+ 2816 | 2 | {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID,HEAP_XMIN_FROZEN}
+(1 row)
+
+SELECT t_infomask, t_infomask2, flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+ LATERAL heap_infomask_flags(t_infomask, t_infomask2, false) m(flags);
+ t_infomask | t_infomask2 | flags
+------------+-------------+-----------------------------------------------------------
+ 2816 | 2 | {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID}
+(1 row)
+
+SELECT heap_infomask_flags(2816, 0);
+ heap_infomask_flags
+----------------------------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID,HEAP_XMIN_FROZEN}
+(1 row)
+
+SELECT heap_infomask_flags(2816, 0, false);
+ heap_infomask_flags
+-----------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID}
+(1 row)
+
+SELECT heap_infomask_flags(2816, 1, true);
+ heap_infomask_flags
+----------------------------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID,HEAP_XMIN_FROZEN}
+(1 row)
+
+SELECT heap_infomask_flags(2816, 1, false);
+ heap_infomask_flags
+-----------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID}
+(1 row)
+
+SELECT heap_infomask_flags(2816, x'FFFF'::integer, true);
+ heap_infomask_flags
+-------------------------------------------------------------------------------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID,HEAP_KEYS_UPDATED,HEAP_HOT_UPDATED,HEAP_ONLY_TUPLE,HEAP_XMIN_FROZEN}
+(1 row)
+
+SELECT heap_infomask_flags(2816, x'FFFF'::integer, false);
+ heap_infomask_flags
+--------------------------------------------------------------------------------------------------------------
+ {HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_INVALID,HEAP_KEYS_UPDATED,HEAP_HOT_UPDATED,HEAP_ONLY_TUPLE}
+(1 row)
+
+SELECT heap_infomask_flags(x'FFFF'::integer, x'FFFF'::integer, false);
+ heap_infomask_flags
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ {HEAP_HASNULL,HEAP_HASVARWIDTH,HEAP_HASEXTERNAL,HEAP_HASOID,HEAP_XMAX_KEYSHR_LOCK,HEAP_COMBOCID,HEAP_XMAX_EXCL_LOCK,HEAP_XMAX_LOCK_ONLY,HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_COMMITTED,HEAP_XMAX_INVALID,HEAP_XMAX_IS_MULTI,HEAP_UPDATED,HEAP_MOVED_OFF,HEAP_MOVED_IN,HEAP_KEYS_UPDATED,HEAP_HOT_UPDATED,HEAP_ONLY_TUPLE}
+(1 row)
+
+SELECT heap_infomask_flags(x'FFFF'::integer, x'FFFF'::integer, true);
+ heap_infomask_flags
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ {HEAP_HASNULL,HEAP_HASVARWIDTH,HEAP_HASEXTERNAL,HEAP_HASOID,HEAP_XMAX_KEYSHR_LOCK,HEAP_COMBOCID,HEAP_XMAX_EXCL_LOCK,HEAP_XMAX_LOCK_ONLY,HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_COMMITTED,HEAP_XMAX_INVALID,HEAP_XMAX_IS_MULTI,HEAP_UPDATED,HEAP_MOVED_OFF,HEAP_MOVED_IN,HEAP_KEYS_UPDATED,HEAP_HOT_UPDATED,HEAP_ONLY_TUPLE,HEAP_XMIN_FROZEN,HEAP_XMAX_IS_LOCKED_ONLY}
+(1 row)
+
+SELECT heap_infomask_flags(0, 0, true);
+ heap_infomask_flags
+---------------------
+ {}
+(1 row)
+
+SELECT heap_infomask_flags(0, 0, false);
+ heap_infomask_flags
+---------------------
+ {}
+(1 row)
+
+SELECT heap_infomask_flags(-1, -1, false);
+ heap_infomask_flags
+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ {HEAP_HASNULL,HEAP_HASVARWIDTH,HEAP_HASEXTERNAL,HEAP_HASOID,HEAP_XMAX_KEYSHR_LOCK,HEAP_COMBOCID,HEAP_XMAX_EXCL_LOCK,HEAP_XMAX_LOCK_ONLY,HEAP_XMIN_COMMITTED,HEAP_XMIN_INVALID,HEAP_XMAX_COMMITTED,HEAP_XMAX_INVALID,HEAP_XMAX_IS_MULTI,HEAP_UPDATED,HEAP_MOVED_OFF,HEAP_MOVED_IN,HEAP_KEYS_UPDATED,HEAP_HOT_UPDATED,HEAP_ONLY_TUPLE}
+(1 row)
+
DROP TABLE test1;
-- check that using any of these functions with a partitioned table would fail
create table test_partitioned (a int) partition by range (a);
diff --git a/contrib/pageinspect/heapfuncs.c b/contrib/pageinspect/heapfuncs.c
index 72d1776..2ef5b39 100644
--- a/contrib/pageinspect/heapfuncs.c
+++ b/contrib/pageinspect/heapfuncs.c
@@ -478,3 +478,123 @@ tuple_data_split(PG_FUNCTION_ARGS)
PG_RETURN_ARRAYTYPE_P(res);
}
+
+/*
+ * Brian Kernighan's popcount algorithm for counting number of set bits in a
+ * mask. The faster methods aren't worth the complexity here.
+ *
+ * See e.g. http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetKernighan
+ *
+ * gcc has __builtin_popcount but there's no standard alternative.
+ */
+static inline int
+pg_popcount32(uint32 mask)
+{
+ unsigned int c; // c accumulates the total bits set in v
+ for (c = 0; mask; c++)
+ {
+ mask &= mask - 1; // clear the least significant bit set
+ }
+ return c;
+}
+
+/*
+ * Infomask flag names. The infomask2 values are shifted into the
+ * high 16 bits.
+ */
+struct infomask_details
+{
+ uint32 flag_value;
+ const char flag_name[24];
+};
+
+#define MASKINFO_LENGTH 19
+static struct infomask_details maskinfo[MASKINFO_LENGTH] =
+ {
+ /* infomask1 values */
+ {(uint32)HEAP_HASNULL, "HEAP_HASNULL"},
+ {(uint32)HEAP_HASVARWIDTH, "HEAP_HASVARWIDTH"},
+ {(uint32)HEAP_HASEXTERNAL, "HEAP_HASEXTERNAL"},
+ {(uint32)HEAP_HASOID, "HEAP_HASOID"},
+ {(uint32)HEAP_XMAX_KEYSHR_LOCK, "HEAP_XMAX_KEYSHR_LOCK"},
+ {(uint32)HEAP_COMBOCID, "HEAP_COMBOCID"},
+ {(uint32)HEAP_XMAX_EXCL_LOCK, "HEAP_XMAX_EXCL_LOCK"},
+ {(uint32)HEAP_XMAX_LOCK_ONLY, "HEAP_XMAX_LOCK_ONLY"},
+ {(uint32)HEAP_XMIN_COMMITTED, "HEAP_XMIN_COMMITTED"},
+ {(uint32)HEAP_XMIN_INVALID, "HEAP_XMIN_INVALID"},
+ {(uint32)HEAP_XMAX_COMMITTED, "HEAP_XMAX_COMMITTED"},
+ {(uint32)HEAP_XMAX_INVALID, "HEAP_XMAX_INVALID"},
+ {(uint32)HEAP_XMAX_IS_MULTI, "HEAP_XMAX_IS_MULTI"},
+ {(uint32)HEAP_UPDATED, "HEAP_UPDATED"},
+ {(uint32)HEAP_MOVED_OFF, "HEAP_MOVED_OFF"},
+ {(uint32)HEAP_MOVED_IN, "HEAP_MOVED_IN"},
+ /* infomask2 values */
+ {((uint32)HEAP_KEYS_UPDATED)<<16, "HEAP_KEYS_UPDATED"},
+ {((uint32)HEAP_HOT_UPDATED)<<16, "HEAP_HOT_UPDATED"},
+ {((uint32)HEAP_ONLY_TUPLE)<<16, "HEAP_ONLY_TUPLE"},
+ };
+
+/*
+ * Decode an infomask, per htup_details.c, into human readable
+ * form.
+ */
+PG_FUNCTION_INFO_V1(heap_infomask_flags);
+
+Datum
+heap_infomask_flags(PG_FUNCTION_ARGS)
+{
+ uint16 t_infomask = PG_GETARG_INT16(0);
+ uint16 t_infomask2 = PG_GETARG_INT16(1);
+ bool include_combined = PG_GETARG_BOOL(2);
+ uint32 combomask = (((uint32)t_infomask2) << 16) + (uint32)t_infomask;
+ unsigned int maxarray = pg_popcount32(combomask);
+ Datum *d;
+ ArrayType *a;
+ int i;
+ int insertpos;
+
+ Assert((t_infomask == 0 && t_infomask2 == 0) == (maxarray == 0));
+
+ if (maxarray == 0)
+ {
+ a = construct_empty_array(TEXTOID);
+ PG_RETURN_POINTER(a);
+ }
+
+ if (include_combined)
+ {
+ maxarray += (t_infomask & HEAP_XMIN_FROZEN) == HEAP_XMIN_FROZEN;
+ maxarray += HEAP_XMAX_IS_LOCKED_ONLY(t_infomask) != 0;
+ maxarray += HEAP_LOCKED_UPGRADED(t_infomask) != 0;
+ }
+
+ d = (Datum *) palloc0(sizeof(Datum) * maxarray);
+
+ insertpos = 0;
+ for (i = 0; i < MASKINFO_LENGTH; ++i)
+ {
+ if ((combomask & maskinfo[i].flag_value) == maskinfo[i].flag_value)
+ d[insertpos++] = CStringGetTextDatum(maskinfo[i].flag_name);
+ }
+
+ /*
+ * These tests are useful to report in the mask we output, since they're
+ * much more simply done here than in SQL, and here they won't get out of
+ * sync with what Pg does if we change it later.
+ */
+ if (include_combined)
+ {
+ if ((t_infomask & HEAP_XMIN_FROZEN) == HEAP_XMIN_FROZEN)
+ d[insertpos++] = CStringGetTextDatum("HEAP_XMIN_FROZEN");
+
+ if (HEAP_XMAX_IS_LOCKED_ONLY(t_infomask))
+ d[insertpos++] = CStringGetTextDatum("HEAP_XMAX_IS_LOCKED_ONLY");
+
+ if (HEAP_LOCKED_UPGRADED(t_infomask))
+ d[insertpos++] = CStringGetTextDatum("HEAP_LOCKED_UPGRADED");
+ }
+
+ a = construct_array(d, insertpos, TEXTOID, -1, false, 'i');
+
+ PG_RETURN_POINTER(a);
+}
diff --git a/contrib/pageinspect/pageinspect--1.6--1.7.sql b/contrib/pageinspect/pageinspect--1.6--1.7.sql
new file mode 100644
index 0000000..b3d1fe4
--- /dev/null
+++ b/contrib/pageinspect/pageinspect--1.6--1.7.sql
@@ -0,0 +1,9 @@
+/* contrib/pageinspect/pageinspect--1.6--1.7.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pageinspect UPDATE TO '1.7'" to load this file. \quit
+
+-- decode infomask flags as human readable flag names
+CREATE FUNCTION heap_infomask_flags(infomask1 integer, infomask2 integer,
+ include_combined boolean DEFAULT true)
+RETURNS text[] STRICT LANGUAGE 'c' AS 'MODULE_PATHNAME','heap_infomask_flags';
diff --git a/contrib/pageinspect/pageinspect.control b/contrib/pageinspect/pageinspect.control
index 1a61c9f..dcfc61f 100644
--- a/contrib/pageinspect/pageinspect.control
+++ b/contrib/pageinspect/pageinspect.control
@@ -1,5 +1,5 @@
# pageinspect extension
comment = 'inspect the contents of database pages at a low level'
-default_version = '1.6'
+default_version = '1.7'
module_pathname = '$libdir/pageinspect'
relocatable = true
diff --git a/contrib/pageinspect/sql/page.sql b/contrib/pageinspect/sql/page.sql
index 493ca9b..2f06c39 100644
--- a/contrib/pageinspect/sql/page.sql
+++ b/contrib/pageinspect/sql/page.sql
@@ -31,6 +31,30 @@ SELECT tuple_data_split('test1'::regclass, t_data, t_infomask, t_infomask2, t_bi
SELECT * FROM fsm_page_contents(get_raw_page('test1', 'fsm', 0));
+-- If we freeze the only tuple on test1, the infomask should
+-- always be the same in all test runs.
+VACUUM FREEZE test1;
+
+SELECT t_infomask, t_infomask2, flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+ LATERAL heap_infomask_flags(t_infomask, t_infomask2, true) m(flags);
+
+SELECT t_infomask, t_infomask2, flags
+FROM heap_page_items(get_raw_page('test1', 0)),
+ LATERAL heap_infomask_flags(t_infomask, t_infomask2, false) m(flags);
+
+SELECT heap_infomask_flags(2816, 0);
+SELECT heap_infomask_flags(2816, 0, false);
+SELECT heap_infomask_flags(2816, 1, true);
+SELECT heap_infomask_flags(2816, 1, false);
+SELECT heap_infomask_flags(2816, x'FFFF'::integer, true);
+SELECT heap_infomask_flags(2816, x'FFFF'::integer, false);
+SELECT heap_infomask_flags(x'FFFF'::integer, x'FFFF'::integer, false);
+SELECT heap_infomask_flags(x'FFFF'::integer, x'FFFF'::integer, true);
+SELECT heap_infomask_flags(0, 0, true);
+SELECT heap_infomask_flags(0, 0, false);
+SELECT heap_infomask_flags(-1, -1, false);
+
DROP TABLE test1;
-- check that using any of these functions with a partitioned table would fail
diff --git a/doc/src/sgml/pageinspect.sgml b/doc/src/sgml/pageinspect.sgml
index ccdaf3e..52bb9d5 100644
--- a/doc/src/sgml/pageinspect.sgml
+++ b/doc/src/sgml/pageinspect.sgml
@@ -151,6 +151,10 @@ test=# SELECT * FROM heap_page_items(get_raw_page('pg_class', 0));
<filename>src/include/access/htup_details.h</> for explanations of the fields
returned.
</para>
+ <para>
+ The <function>heap_infomask_flags</function> function can be used to unpack the
+ recognised bits of the infomasks of heap tuples.
+ </para>
</listitem>
</varlistentry>
@@ -206,6 +210,34 @@ test=# SELECT * FROM heap_page_item_attrs(get_raw_page('pg_class', 0), 'pg_class
<varlistentry>
<term>
+ <function>heap_infomask_flags(infomask1 integer, infomask2 integer, include_combined bool) returns text[]</function>
+ <indexterm>
+ <primary>heap_infomask_flags</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ <function>heap_infomask_flags</function> decodes the
+ <structfield>t_infomask1</structfield> and
+ <structfield>t_infomask2</structfield> returned by
+ <function>heap_page_items</function> into a human-readable array of flag
+ names. This can be used to see the tuple hint bits etc.
+ </para>
+ <para>
+ If include_combined is set (the default), combination flags like
+ <literal>HEAP_XMIN_FROZEN</literal> are also output. The original fields
+ are not filtered out, so e.g. a frozen tuple will have
+ <literal>HEAP_XMIN_FROZEN, HEAP_XMIN_COMMITTED, HEAP_XMIN_INVALID</literal>.
+ </para>
+ <para>
+ For the meaning of these flags see
+ <filename>src/include/access/htup_details.h</>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term>
<function>fsm_page_contents(page bytea) returns text</function>
<indexterm>
<primary>fsm_page_contents</primary>
--
2.9.4
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
