On 2/8/19, Kyotaro HORIGUCHI <[email protected]> wrote:
> [v2 patch]
I poked this around a bit and found that this mechanism only works for
bootstrapped tables, as those are the only ones where we can scribble
on pg_attribute entries directly during bootstrap. As such, with this
patch we cannot perform ALTER TABLE for pg_index or pg_largeobject*
[1]. IMHO, it's not worth it to introduce new notation unless it
offers complete coverage. If we're willing to only solve the problem
for pg_class and pg_attribute, I'd rather mark the table rather than
the columns, because we already have visibility into CATALOG_VARLEN.
(rough example attached)
On 2/14/19, Peter Eisentraut <[email protected]> wrote:
> That already exists: 'm': Value can be stored compressed inline
>
> I agree that it seems we should be using that for those tables that
> don't have a toast table. Maybe the genbki stuff could do it
> automatically for the appropriate catalogs.
The docs say:
(Actually, out-of-line storage will still be performed for such
columns, but only as a last resort when there is no other way to make
the row small enough to fit on a page.)
If we allow 'm' as an exception, would that interfere with this? My
demo patch has this just in case:
- if (att->attstorage != 'p')
+ if (att->attstorage != 'p' &&
+ !(att->attstorage == 'm' && IsCatalogRelation(rel)))
has_toastable_attrs = true;
Here's another idea: During initdb, do "ALTER TABLE ALTER COLUMN xyz
SET STORAGE MAIN;"
In initdb, we already pass "-O" to allow system table mods, so I think
we would have to just make sure this one statement doesn't try to add
a toast table. We could have genbki.pl emit a file with SQL statements
to cover all necessary tables/columns.
[1]
https://www.postgresql.org/message-id/20180928190630.crt43sk5zd5p555h%40alvherre.pgsql
--
John Naylor https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/src/backend/catalog/Catalog.pm b/src/backend/catalog/Catalog.pm
index 3bf308fe3b..885df79f92 100644
--- a/src/backend/catalog/Catalog.pm
+++ b/src/backend/catalog/Catalog.pm
@@ -124,6 +124,7 @@ sub ParseHeader
$catalog{rowtype_oid_macro} = '';
}
$catalog{schema_macro} = /BKI_SCHEMA_MACRO/ ? 1 : 0;
+ $catalog{no_toast} = /BKI_NO_TOAST/ ? 1 : 0;
$declaring_attributes = 1;
}
elsif ($is_client_code)
diff --git a/src/backend/catalog/genbki.pl b/src/backend/catalog/genbki.pl
index 4935e00fb2..b4777e5e5a 100644
--- a/src/backend/catalog/genbki.pl
+++ b/src/backend/catalog/genbki.pl
@@ -658,7 +658,7 @@ sub gen_pg_attribute
$row{attnum} = $attnum;
$row{attrelid} = $table->{relation_oid};
- morph_row_for_pgattr(\%row, $schema, $attr, $priornotnull);
+ morph_row_for_pgattr($table, \%row, $schema, $attr, $priornotnull);
$priornotnull &= ($row{attnotnull} eq 't');
# If it's bootstrapped, put an entry in postgres.bki.
@@ -691,7 +691,7 @@ sub gen_pg_attribute
$row{attrelid} = $table->{relation_oid};
$row{attstattarget} = '0';
- morph_row_for_pgattr(\%row, $schema, $attr, 1);
+ morph_row_for_pgattr($table, \%row, $schema, $attr, 1);
print_bki_insert(\%row, $schema);
}
}
@@ -707,7 +707,7 @@ sub gen_pg_attribute
# Any value not handled here must be supplied by caller.
sub morph_row_for_pgattr
{
- my ($row, $pgattr_schema, $attr, $priornotnull) = @_;
+ my ($table, $row, $pgattr_schema, $attr, $priornotnull) = @_;
my $attname = $attr->{name};
my $atttype = $attr->{type};
@@ -719,9 +719,17 @@ sub morph_row_for_pgattr
$row->{atttypid} = $type->{oid};
$row->{attlen} = $type->{typlen};
$row->{attbyval} = $type->{typbyval};
- $row->{attstorage} = $type->{typstorage};
$row->{attalign} = $type->{typalign};
+ if ($table->{no_toast} && $attr->{is_varlen})
+ {
+ $row->{attstorage} = 'm';
+ }
+ else
+ {
+ $row->{attstorage} = $type->{typstorage};
+ }
+
# set attndims if it's an array type
$row->{attndims} = $type->{typcategory} eq 'A' ? '1' : '0';
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 77be19175a..37e494b205 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -18,6 +18,7 @@
#include "access/tuptoaster.h"
#include "access/xact.h"
#include "catalog/binary_upgrade.h"
+#include "catalog/catalog.h"
#include "catalog/dependency.h"
#include "catalog/heap.h"
#include "catalog/index.h"
@@ -435,7 +436,8 @@ needs_toast_table(Relation rel)
maxlength_unknown = true;
else
data_length += maxlen;
- if (att->attstorage != 'p')
+ if (att->attstorage != 'p' &&
+ !(att->attstorage == 'm' && IsCatalogRelation(rel)))
has_toastable_attrs = true;
}
}
diff --git a/src/include/catalog/genbki.h b/src/include/catalog/genbki.h
index 1b8e4e9e19..1984bbc426 100644
--- a/src/include/catalog/genbki.h
+++ b/src/include/catalog/genbki.h
@@ -27,6 +27,7 @@
#define BKI_SHARED_RELATION
#define BKI_ROWTYPE_OID(oid,oidmacro)
#define BKI_SCHEMA_MACRO
+#define BKI_NO_TOAST
/* Options that may appear after an attribute (on the same line) */
#define BKI_FORCE_NULL
diff --git a/src/include/catalog/pg_attribute.h b/src/include/catalog/pg_attribute.h
index a6ec122389..66120244f5 100644
--- a/src/include/catalog/pg_attribute.h
+++ b/src/include/catalog/pg_attribute.h
@@ -34,7 +34,7 @@
* You may need to change catalog/genbki.pl as well.
* ----------------
*/
-CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,AttributeRelation_Rowtype_Id) BKI_SCHEMA_MACRO
+CATALOG(pg_attribute,1249,AttributeRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(75,AttributeRelation_Rowtype_Id) BKI_SCHEMA_MACRO BKI_NO_TOAST
{
Oid attrelid; /* OID of relation containing this attribute */
NameData attname; /* name of attribute */
diff --git a/src/include/catalog/pg_class.h b/src/include/catalog/pg_class.h
index 5d82ce09a6..151b195f02 100644
--- a/src/include/catalog/pg_class.h
+++ b/src/include/catalog/pg_class.h
@@ -26,7 +26,7 @@
* typedef struct FormData_pg_class
* ----------------
*/
-CATALOG(pg_class,1259,RelationRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(83,RelationRelation_Rowtype_Id) BKI_SCHEMA_MACRO
+CATALOG(pg_class,1259,RelationRelationId) BKI_BOOTSTRAP BKI_ROWTYPE_OID(83,RelationRelation_Rowtype_Id) BKI_SCHEMA_MACRO BKI_NO_TOAST
{
Oid oid; /* oid */
NameData relname; /* class name */
