PostgreSQL中JSON数据类型的大小限制 [英] Size limit of JSON data type in PostgreSQL

问题描述

有人知道PostgreSQL 9.2中JSON数据类型的大小限制是什么吗?

Does anyone know what is the limit on the size of JSON data type in PostgreSQL 9.2?

推荐答案

查看PostgreSQL 9.2.1的源代码:

Looking at the source for PostgreSQL 9.2.1:

Source: postgresql-9.2.1\src\backend\utils\adt\json.c:
/*
 * Input.
 */
Datum
json_in(PG_FUNCTION_ARGS)
{
    char       *text = PG_GETARG_CSTRING(0);

    json_validate_cstring(text);

    /* Internal representation is the same as text, for now */
    PG_RETURN_TEXT_P(cstring_to_text(text));
}

PostgreSQL 9.3.5更新:

Update for PostgreSQL 9.3.5:

json_in函数中的代码已更改，但json内部表示仍为文本:

The code has changed in the json_in function, but the json internal representation is still text:

Source: postgresql-9.3.5\src\backend\utils\adt\json.c:
/*
 * Input.
 */
Datum
json_in(PG_FUNCTION_ARGS)
{
    char       *json = PG_GETARG_CSTRING(0);
    text       *result = cstring_to_text(json);
    JsonLexContext *lex;

    /* validate it */
    lex = makeJsonLexContext(result, false);
    pg_parse_json(lex, &nullSemAction);

    /* Internal representation is the same as text, for now */
    PG_RETURN_TEXT_P(result);
}

因此，看来至少到目前为止，json与text数据类型相同，但具有JSON验证. text数据类型的最大大小为 1GB .

So it appears that, for now at least, json is the same as a text datatype but with JSON validation. The text datatype's maximum size is 1GB.

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