ASE v15中的应用程序跟踪tracefile特性
Sybase 在ASE v15.0.2 中新增了“应用程序”跟踪这个特性。
您可以利用“应用程序”跟踪功能收集一个正在运行中的客户会话的有用诊断信息，包括：执行查询、IO 消耗等；并且ASE 会自动把收集到的跟踪信息写到一个文本文件中。可以很方便得用这个特性来诊断一些系统性能瓶颈。
您只需要知道想要跟踪的会话的SPID(Server Process ID) 就可以对那个会话进行跟踪监控。应用系统的用户只需要被授予“set tracing ”权限就可以利用“应用程序”跟踪对自己的会话信息进行跟踪。
执行“应用程序”跟踪需要具有 set tracing 的权限。主要有两类用户：第一：具有sa或者sso角色的用户（默认具有set tracing权限）；第二:被赋予了set tracing 执行权限的用户。下面会分别予以介绍。
（1） 具有管理员特权的用户（属于 sa 或者 sso 角色）
对其他用户连接会话启用“应用程序”跟踪，执行：
set tracefile "<file-path>" for <spid>
关闭刚才打开的针对其他用户连接会话的跟踪，需要执行：
set tracefile off for <spid>
备注：
(1) 针对某个用户会话启用跟踪时，需要知道它的SPID 并填写跟踪结果文件保存的路径。如果没有指定跟踪结果文件保存的路径，那么ASE 会自动保存到$SYBASE 目录下。
(2) 在一个会话中，只能有一个set tracefile 为启用状态；并且，某一个SPID 不能被多个会话同时跟踪。
(3) 当被跟踪的会话自己退出，或者跟踪被手动关闭时，ASE 会生成跟踪结果文件。
(4) 在“应用程序”跟踪的过程中，如果跟踪结果文件所在的磁盘空间被耗尽，那么ASE 会自动保存跟踪文件并结束本次“应用程序”跟踪。
(5) 用sp_helpapptrace 存储过程来查看当前正在执行中的所有应用程序跟踪信息。
（2） 被赋予“set tracing” 权限的应用程序用户
对自己的会话启用跟踪，执行：
set tracefile "<file-path>"
结束对自己的会话上的跟踪，使用：
set tracefile off
备注： 不能使用sp_helpapptrace过程来查看正在被跟踪的会话。
（3 ） 哪些信息可被用来跟踪？
在“应用程序”跟踪中可以追踪以下的set option 命令。
set show_sqltext <on/off>
set showplan <on/off>
set statistics io <on/off>
set statistics time <on/off>
set statistics plancost <on/off>
set option 的子命令也可被用来跟踪。
set option show_lop <normal/brief/long/on/off> ---显示使用的逻辑操作数量
set option show_managers <normal/brief/long/on/off> --- 显示使用的数据结构管理器的数量
set option show_log_props <normal/brief/long/on/off> --- 显示所用的逻辑属性
set option show_parallel <normal/brief/long/on/off> --- 显示并行查询优化器信息
set option show_histograms <normal/brief/long/on/off> --- 显示直方图统计信息处理过程
set option show_abstract_plan <normal/brief/long/on/off> --- 显示虚拟查询计划具体信息
set option show_search_engine <normal/brief/long/on/off> --- 显示搜索引擎的详细信息
set option show_counters <normal/brief/long/on/off> --- 显示优化器找到的计划的数量
set option show_best_plan <normal/brief/long/on/off> --- 显示最优计划信息
set option show_code_gen <normal/brief/long/on/off> --- 显示代码产生器的信息
set option show_pio_costing <normal/brief/long/on/off> --- 显示估计的物理IO数
set option show_lio_costing <normal/brief/long/on/off> --- 显示估计的逻辑IO数
set option show_elimination <normal/brief/long/on/off> --- 显示分区消除信息
（4） 例子 （使用具有sa 和sso 角色的用户）
在一个会话中执行如下的命令：
set tracefile "c:/tmp/trace-spid-16.txt" for 16
set show_sqltext on
set showplan on
go
sp_helpapptrace
go
traced_spid tracer_spid trace_file
----------- ----------- ----------------------------
16 19 c:/tmp/ase-trace-spid-16.txt
(1 row affected)
(return status = 0)
上面的输出结果表明该会话的spid为16。
在另外一个会话中，在被监控的用户会话spid=16中执行sp_helpdb过程。
set tracefile off for 16
go
sp_helpapptrace
go
traced_spid tracer_spid trace_file
----------- ----------- ----------
(0 rows affected)
(return status = 0)
跟踪结果信息如下：
================================================================================
Application Tracing report for spid -1 from application "isql"
run by login "sa" on host "TEST"
Tracing started on 2010/04/24 17:08:10.23
================================================================================
No useful sqltext available.
QUERY PLAN FOR STATEMENT 1 (at line 1).
STEP 1
The type of query is EXECUTE.
2010/04/24 17:08:10.23
No useful sqltext available.
Sproc: sp_helpdb, Line: 0
QUERY PLAN FOR STATEMENT 1 (at line 0).
STEP 1
The type of query is DECLARE.
Sproc: sp_helpdb, Line: 38
QUERY PLAN FOR STATEMENT 2 (at line 38).
STEP 1
The type of query is COND.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 40
QUERY PLAN FOR STATEMENT 3 (at line 40).
STEP 1
The type of query is SET OPTION OFF.
Sproc: sp_helpdb, Line: 43
QUERY PLAN FOR STATEMENT 4 (at line 43).
STEP 1
The type of query is SET OPTION ON.
Sproc: sp_helpdb, Line: 45
QUERY PLAN FOR STATEMENT 5 (at line 45).
STEP 1
The type of query is SELECT.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 47
QUERY PLAN FOR STATEMENT 6 (at line 47).
STEP 1
The type of query is COND.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 49
QUERY PLAN FOR STATEMENT 7 (at line 49).
STEP 1
The type of query is COND.
3 operator(s) under root
|ROOT:EMIT Operator (VA = 3)
|
| |RESTRICT Operator (VA = 2)(0)(0)(0)(4)(0)
| |
| | |SCALAR AGGREGATE Operator (VA = 1)
| | | Evaluate Ungrouped ANY AGGREGATE.
| | | Scanning only up to the first qualifying row.
| | |
| | | |SCAN Operator (VA = 0)
| | | | FROM TABLE
| | | | master.dbo.sysmessages
| | | | Index : ncsysmessages
| | | | Forward Scan.
| | | | Positioning by key.
| | | | Index contains all needed columns. Base table will not be read.
| | | | Keys are:
| | | | error ASC
| | | | Using I/O Size 2 Kbytes for index leaf pages.
| | | | With LRU Buffer Replacement Strategy for index leaf pages.
Sproc: sp_helpdb, Line: 53
QUERY PLAN FOR STATEMENT 8 (at line 53).
STEP 1
The type of query is SELECT.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 55
QUERY PLAN FOR STATEMENT 9 (at line 55).
STEP 1
The type of query is COND.
3 operator(s) under root
|ROOT:EMIT Operator (VA = 3)
|
| |RESTRICT Operator (VA = 2)(0)(0)(0)(4)(0)
| |
| | |SCALAR AGGREGATE Operator (VA = 1)
| | | Evaluate Ungrouped ANY AGGREGATE.
| | | Scanning only up to the first qualifying row.
| | |
| | | |SCAN Operator (VA = 0)
| | | | FROM TABLE
| | | | master.dbo.sysmessages
| | | | Index : ncsysmessages
| | | | Forward Scan.
| | | | Positioning by key.
| | | | Index contains all needed columns. Base table will not be read.
| | | | Keys are:
| | | | error ASC
| | | | Using I/O Size 2 Kbytes for index leaf pages.
| | | | With LRU Buffer Replacement Strategy for index leaf pages.
Sproc: sp_helpdb, Line: 59
QUERY PLAN FOR STATEMENT 10 (at line 59).
STEP 1
The type of query is SELECT.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 0
QUERY PLAN FOR STATEMENT 11 (at line 0).
STEP 1
The type of query is GOTO.
Sproc: sp_helpdb, Line: 0
QUERY PLAN FOR STATEMENT 12 (at line 0).
STEP 1
The type of query is GOTO.
Sproc: sp_helpdb, Line: 62
QUERY PLAN FOR STATEMENT 13 (at line 62).
STEP 1
The type of query is SET OPTION ON.
Sproc: sp_helpdb, Line: 69
QUERY PLAN FOR STATEMENT 14 (at line 69).
STEP 1
The type of query is COND.
1 operator(s) under root
|ROOT:EMIT Operator (VA = 1)
|
| |SCALAR Operator (VA = 0)
Sproc: sp_helpdb, Line: 70
QUERY PLAN FOR STATEMENT 15 (at line 70).
STEP 1
The type of query is SELECT.
2 operator(s) under root
|ROOT:EMIT Operator (VA = 2)
|
| |SCALAR AGGREGATE Operator (VA = 1)
| | Evaluate Ungrouped COUNT AGGREGATE.
| |
| | |SCAN Operator (VA = 0)
| | | FROM TABLE
| | | master.dbo.sysdatabases
| | | Index : ncsysdatabases
| | | Forward Scan.
| | | Positioning at index start.
| | | Index contains all needed columns. Base table will not be read.
| | | Using I/O Size 2 Kbytes for index leaf pages.
| | | With LRU Buffer Replacement Strategy for index leaf pages.
Sproc: sp_helpdb, Line: 73
QUERY PLAN FOR STATEMENT 16 (at line 73).
STEP 1
The type of query is SELECT.
3 operator(s) under root
|ROOT:EMIT Operator (VA = 3)
|
| |SCALAR AGGREGATE Operator (VA = 2)
| | Evaluate Ungrouped COUNT AGGREGATE.
| |
| | |RESTRICT Operator (VA = 1)(0)(0)(0)(6)(0)
| | |
| | | |SCAN Operator (VA = 0)
| | | | FROM TABLE
| | | | master.dbo.sysdatabases
| | | | Using Clustered Index.
| | | | Index : cdatabases
| | | | Forward Scan.
| | | | Positioning at index start.
| | | | Index contains all needed columns. Base table will not be read.
| | | | Using I/O Size 2 Kbytes for index leaf pages.
| | | | With LRU Buffer Replacement Strategy for index leaf pages.
Sproc: sp_helpdb, Line: 80
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