ERROR: could not form array type name for type
遇到了一个用户创建表的报错。比较有意思。一起来看看这个问题。
众所周知,PG的relname最大只有63,如果超过63则会自动截断。
类似这样
xxx=# create table xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60xxxx(c1 int,c2 varchar,c3 varchar,c4 varchar);
NOTICE: identifier "xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60xxxx" will be truncated to "xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60xxx"
CREATE TABLE
当我需要批量创建99张表,并通过数字后缀来区分,如果用户的表名刚好用满63个字符时,那么就会在创建尾数71号表的时候出现这个报错,
ERROR: could not form array type name for type “xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_71”
这个报错是创建类型时的报错。postgres每创建一张表,会默认创建出一个和表相同的组合类型和数组类型。这里似乎有什么瓶颈。
先尝试复现一下。
xxx=# CREATE OR REPLACE procedure create_tables(schema_name text,table_prefix text,num_tables integer) AS $$
DECLARE
i integer;
table_name text;
sql_query text;
BEGIN
drop schema if exists xxx cascade;
create schema if not exists xxx;
FOR i IN 1..num_tables LOOP
table_name := table_prefix || '_' || i;
sql_query := 'CREATE TABLE ' || schema_name || '.' || table_name || ' (id int PRIMARY KEY,name TEXT)';
execute sql_query;
commit;
END LOOP;
END;
$$ LANGUAGE plpgsql;
CREATE PROCEDURE
xxx=# call create_tables('xxx','xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60',99);
NOTICE: schema "xxx" does not exist, skipping
ERROR: could not form array type name for type "xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_71"
CONTEXT: SQL statement "CREATE TABLE xxx.xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_71 (id int PRIMARY KEY,name TEXT)"
PL/pgSQL function create_tables(text,text,integer) line 12 at EXECUTE
可以看到,这种场景下,我们创建表到70个之后就无法继续创建默认类型了。
是什么原因导致的呢?我们看下报错出处。
可以看到数据库在创建默认类型的规则,对于冲突的处理是在函数makeUniqueTypeName中进行的。
而makeUniqueTypeName函数中对于冲突的名字是通过在typname前面加下划线的方式来处理的,如果还是冲突,那就继续在前面再加一个下划线,这种方式略显粗暴。
当typname超过63,则会使用truncate_identifier函数截断。typname被截断之后,最后的几个特异性字符就会丢失,导致类型名重复,然后会一直尝试加下划线,随着下划线的增加,最终下划线会将63字节全部占满,导致无法创建。
看下typname
xxx=# select typname from pg_type where typowner !=10;
typname
-----------------------------------------------------------------
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_1
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_1
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_2
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_2
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_3
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_3
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_4
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_4
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_5
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_5
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_6
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_6
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_7
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_7
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_8
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_8
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_9
_xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_9
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_10
__xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_11
___xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_12
____xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx6
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_13
_____xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_14
______xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_15
_______xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_16
________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_17
_________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_18
__________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_19
___________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_20
____________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50x
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_21
_____________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_22
______________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx5
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_23
_______________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_24
________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_25
_________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_26
__________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_27
___________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_28
____________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_29
_____________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_30
______________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40x
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_31
_______________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_32
________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx4
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_33
_________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_34
__________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_35
___________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_36
____________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_37
_____________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_38
______________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_39
_______________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_40
________________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30x
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_41
_________________________________xxxxxxxx10xxxxxxxx20xxxxxxxx30
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_42
__________________________________xxxxxxxx10xxxxxxxx20xxxxxxxx3
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_43
___________________________________xxxxxxxx10xxxxxxxx20xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_44
____________________________________xxxxxxxx10xxxxxxxx20xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_45
_____________________________________xxxxxxxx10xxxxxxxx20xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_46
______________________________________xxxxxxxx10xxxxxxxx20xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_47
_______________________________________xxxxxxxx10xxxxxxxx20xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_48
________________________________________xxxxxxxx10xxxxxxxx20xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_49
_________________________________________xxxxxxxx10xxxxxxxx20xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_50
__________________________________________xxxxxxxx10xxxxxxxx20x
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_51
___________________________________________xxxxxxxx10xxxxxxxx20
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_52
____________________________________________xxxxxxxx10xxxxxxxx2
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_53
_____________________________________________xxxxxxxx10xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_54
______________________________________________xxxxxxxx10xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_55
_______________________________________________xxxxxxxx10xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_56
________________________________________________xxxxxxxx10xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_57
_________________________________________________xxxxxxxx10xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_58
__________________________________________________xxxxxxxx10xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_59
___________________________________________________xxxxxxxx10xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_60
____________________________________________________xxxxxxxx10x
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_61
_____________________________________________________xxxxxxxx10
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_62
______________________________________________________xxxxxxxx1
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_63
_______________________________________________________xxxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_64
________________________________________________________xxxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_65
_________________________________________________________xxxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_66
__________________________________________________________xxxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_67
___________________________________________________________xxxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_68
____________________________________________________________xxx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_69
_____________________________________________________________xx
xxxxxxxx10xxxxxxxx20xxxxxxxx30xxxxxxxx40xxxxxxxx50xxxxxxxx60_70
______________________________________________________________x
(140 rows)
当第10个表创建的时候,因其名称被截断,所以开始加下划线,一直加到63个字符,最终只能创建61+9张表。所以会报错在第70张表上。
这种问题如何解决呢?
之前的想法是在命名规则里面增加一个特异性数字。
不过刚才看到社区搜到修复的patch已经合入master了。不用我们操心了,直接看下patch,思路是截断的时候多截断一些字符,然后把一个数字拼接进去。
https://github.com/postgres/postgres/commit/70988b7b0a0bd03c59a2314d0b5bcf2135692349
/*
* Per ancient Postgres tradition,array type names are made by prepending
* an underscore to the base type name. Much client code knows that
* convention,so don't muck with it. However,the tradition is less
* clear about what to do in the corner cases where the resulting name is
* too long or conflicts with an existing name. Our current rules are (1)
* truncate the base name on the right as needed,and (2) if there is a
* conflict,append another underscore and some digits chosen to make it
* unique. This is similar to what ChooseRelationName() does.
*
* The actual name generation can be farmed out to makeObjectName() by
* giving it an empty first name component.
*/
/* First,try with no numeric suffix */
arr_name = makeObjectName("", typeName, NULL);
for (;;)
{
if (!SearchSysCacheExists2(TYPENAMENSP,
CStringGetDatum(arr_name),
ObjectIdGetDatum(typeNamespace)))
break;
/* That attempt conflicted. Prepare a new name with some digits. */
pfree(arr_name);
snprintf(suffix, sizeof(suffix), "%d", ++pass);
arr_name = makeObjectName("", suffix);
}
原文地址:https://blog.csdn.net/u010825173/article/details/129973298
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