标签
PostgreSQL , GET , STACKED , DIAGNOSTICS
背景
使用GET STACKED DIAGNOSTICS捕获异常时的STACK内容。
使用GET DIAGNOSTICS捕获运行过程中的状态值。
GET DIAGNOSTICS捕获运行过程中的状态值
There are several ways to determine the effect of a command. The first method is to use the GET DIAGNOSTICS command, which has the form:
GET [ CURRENT ] DIAGNOSTICS variable { = | := } item [ , ... ];
GET DIAGNOSTICS integer_var = ROW_COUNT;
| Name | Type | Description |
|---|---|---|
| ROW_COUNT | bigint | the number of rows processed by the most recent SQL command |
| RESULT_OID | oid | the OID of the last row inserted by the most recent SQL command (only useful after an INSERT command into a table having OIDs) |
| PG_CONTEXT | text | line(s) of text describing the current call stack (see Section 43.6.8) |
The GET DIAGNOSTICS command, previously described in Section 43.5.5, retrieves information about current execution state (whereas the GET STACKED DIAGNOSTICS command discussed above reports information about the execution state as of a previous error).
例子
CREATE OR REPLACE FUNCTION outer_func() RETURNS integer AS $$
BEGIN
RETURN inner_func();
END;
$$ LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION inner_func() RETURNS integer AS $$
DECLARE
stack text;
BEGIN
GET DIAGNOSTICS stack = PG_CONTEXT;
RAISE NOTICE E'--- Call Stack ---\n%', stack;
RETURN 1;
END;
$$ LANGUAGE plpgsql;
SELECT outer_func();
NOTICE: --- Call Stack ---
PL/pgSQL function inner_func() line 5 at GET DIAGNOSTICS
PL/pgSQL function outer_func() line 3 at RETURN
CONTEXT: PL/pgSQL function outer_func() line 3 at RETURN
outer_func
------------
1
(1 row)
GET STACKED DIAGNOSTICS捕获异常时的STACK内容
GET STACKED DIAGNOSTICS ... PG_EXCEPTION_CONTEXT returns the same sort of stack trace, but describing the location at which an error was detected, rather than the current location.
| Name | Type | Description |
|---|---|---|
| RETURNED_SQLSTATE | text | the SQLSTATE error code of the exception |
| COLUMN_NAME | text | the name of the column related to exception |
| CONSTRAINT_NAME | text | the name of the constraint related to exception |
| PG_DATATYPE_NAME | text | the name of the data type related to exception |
| MESSAGE_TEXT | text | the text of the exception's primary message |
| TABLE_NAME | text | the name of the table related to exception |
| SCHEMA_NAME | text | the name of the schema related to exception |
| PG_EXCEPTION_DETAIL | text | the text of the exception's detail message, if any |
| PG_EXCEPTION_HINT | text | the text of the exception's hint message, if any |
| PG_EXCEPTION_CONTEXT | text | line(s) of text describing the call stack at the time of the exception (see Section 43.6.8) |
例子
DECLARE
text_var1 text;
text_var2 text;
text_var3 text;
BEGIN
-- some processing which might cause an exception
...
EXCEPTION WHEN OTHERS THEN
GET STACKED DIAGNOSTICS text_var1 = MESSAGE_TEXT,
text_var2 = PG_EXCEPTION_DETAIL,
text_var3 = PG_EXCEPTION_HINT;
END;
参考
https://www.postgresql.org/docs/11/static/plpgsql-control-structures.html#PLPGSQL-CALL-STACK
https://www.postgresql.org/docs/11/static/plpgsql-statements.html
《Using "GET DIAGNOSTICS integer_var = ROW_COUNT;" capture rows effect by the last SQL》
