Oracle® TimesTen In-Memory Database Troubleshooting Procedures Guide Release 11.2.1 Part Number E13075-02 |
|
|
View PDF |
This chapter describes how to use the TimesTen utilities and other tools that are used to diagnose problems with the TimesTen data store. This chapter includes the following topics:
The ttIsql
utility allows you to interactively execute SQL statements and report status information on your data store.
All TimesTen SQL operations can be executed from a ttIsql
Command>
prompt.
Example 1-1 Using the ttIsql utility
To start the ttIsql
utility for the demo data store, enter:
% ttIsql demo
You should see output similar to the following:
Copyright (c) 1996-2007, Oracle. All rights reserved. Type ? or "help" for help, type "exit" to quit ttIsql. connect "DSN=demo"; Connection successful: DSN=demo;UID=ttuser;DataStore=c:\temp\demo; DatabaseCharacterSet=US7ASCII;ConnectionCharacterSet=US7ASCII; DRIVER=C:\WINDOWS\system32\ttdv70.dll;Authenticate=0;PermSize=20;TypeMode=0; (Default setting AutoCommit=1) Command>
You can then execute SQL statements or ttIsql
commands at the Command>
prompt.
"Using the ttIsql Utility" in the Oracle TimesTen In-Memory Database Operations Guide describes how to use the most common ttIsql
commands. The following ttIsql
commands are commonly used when troubleshooting:
monitor
formats the contents of the SYS.MONITOR table.
See "Displaying data store information" in the Oracle TimesTen In-Memory Database Operations Guide.
dssize
prints data store size information.
See "Displaying data store information" in the Oracle TimesTen In-Memory Database Operations Guide.
showplan
prints the optimizer execution plans for selects/updates/deletes in this transaction.
See "Viewing and changing query optimizer plans" in the Oracle TimesTen In-Memory Database Operations Guide.
isolation
sets or displays the isolation level.
See "Working with transactions" in the Oracle TimesTen In-Memory Database Operations Guide.
timing
prints query timing.
See "Timing ODBC function calls" in the Oracle TimesTen In-Memory Database Operations Guide.
optprofile
prints the current optimizer flag settings and join order.
See "Viewing and changing query optimizer plans" in the Oracle TimesTen In-Memory Database Operations Guide.
For the full list of ttIsql
features, see the lists of options and commands under the description of the ttIsql
utility in the Oracle TimesTen In-Memory Database Reference.
Use the ttStatus
utility to check the status of the TimesTen daemon and the state of all TimesTen -connections.
Example 1-2 ttStatus shows TimesTen daemon is not running
In this example, the output from ttStatus
indicates that no TimesTen daemon is running. If the daemon has stopped unexpectedly, see "No response from TimesTen daemon or subdaemon" for troubleshooting information.
On Windows:
C:\>ttStatus ttStatus: Could not connect to the TimesTen service. If the TimesTen service is not running, please start it by running "ttDaemonAdmin -start".
On UNIX platforms:
$ ttStatus ttStatus: Could not connect to the TimesTen daemon. If the TimesTen daemon is not running, please start it by running "ttDaemonAdmin -start".
Example 1-3 ttStatus shows TimesTen daemon is running
In this example, the output from ttStatus
indicates that the TimesTen daemon is running. It recognizes one data store named demo
.
The first line indicates that the TimesTen daemon is running as process 884 on port 17000 for the TimesTen instance MYINSTANCE
. The second line indicates the TimesTen server daemon is running as process 2308 on port 17002.
There are currently seven connections to the data store: one user and six subdaemon connections. You may see up to 2047 connections.
The restart policies for the cache agent and the replication agent in the data store are set to manual
.
Note:
This example was produced on Windows. The results are the same on UNIX platforms except for the formats of the data store path and the shared memory key.C:\>ttStatus TimesTen status report as of Thu Jan 25 15:45:11 2007 Daemon pid 884 port 17000 instance MYINSTANCE TimesTen server pid 2308 started on port 17002 TimesTen webserver pid 2188 started on port 17004 ------------------------------------------------------------------------ Data store c:\temp\demo There are 7 connections to the data store Data store is in shared mode Shared Memory KEY Global\DBI45b94095.1.SHM.4 HANDLE 0x278 Type PID Context Connection Name ConnID Process 4616 0x00d08820 demo 1 Subdaemon 2136 0x00526768 Worker 2042 Subdaemon 2136 0x0072e750 Flusher 2043 Subdaemon 2136 0x007348b8 Checkpoint 2044 Subdaemon 2136 0x067b0068 Aging 2045 Subdaemon 2136 0x067c0040 Monitor 2047 Subdaemon 2136 0x068404c8 HistGC 2046 Replication policy : Manual Cache agent policy : Manual ------------------------------------------------------------------------ End of report
Example 1-4 ttStatus shows replication information
In this example, the output from ttStatus
indicates that the TimesTen daemon is running. It recognizes three data stores: demo
, subscriber1ds
, and masterds
. The subscriber1ds
and masterds
data stores are replicated data stores. In this example, the output from ttStatus
indicates that the replication agents for the replicated data stores have been started. Bidirectional replication has been configured between masterds
and subscriber1ds
. Each replication agent has five connections to the data store.
C:\>ttStatus TimesTen status report as of Thu Jan 25 16:23:33 2007 Daemon pid 5088 port 17000 instance MYINSTANCE TimesTen server pid 4344 started on port 17002 TimesTen webserver pid 4216 started on port 17004 ------------------------------------------------------------------------ Data store c:\temp\subscriber1ds There are 12 connections to the data store Data store is in shared mode Shared Memory KEY Global\DBI45b9471c.2.SHM.2 HANDLE 0x280 Type PID Context Connection Name ConnID Process 1244 0x00d08fb0 subscriber1ds 1 Replication 4548 0x00aed2f8 LOGFORCE 4 Replication 4548 0x00b03470 TRANSMITTER 5 Replication 4548 0x00b725a8 RECEIVER 6 Replication 4548 0x00b82808 REPHOLD 2 Replication 4548 0x00b98980 REPLISTENER 3 Subdaemon 2752 0x00526768 Worker 2042 Subdaemon 2752 0x0072a758 Flusher 2043 Subdaemon 2752 0x007308c0 Checkpoint 2044 Subdaemon 2752 0x00736a28 HistGC 2046 Subdaemon 2752 0x067f02f8 Aging 2045 Subdaemon 2752 0x068364a0 Monitor 2047 Replication policy : Manual Replication agent is running. Cache agent policy : Manual ------------------------------------------------------------------------ Data store c:\temp\masterds There are 12 connections to the data store Data store is in shared mode Shared Memory KEY Global\DBI45b945d0.0.SHM.6 HANDLE 0x2bc Type PID Context Connection Name ConnID Process 5880 0x00d09008 masterds 1 Replication 3728 0x00aed570 LOGFORCE 4 Replication 3728 0x00b036e8 TRANSMITTER 5 Replication 3728 0x00b168b8 REPHOLD 3 Replication 3728 0x00b1ca20 REPLISTENER 2 Replication 3728 0x00b22b88 RECEIVER 6 Subdaemon 3220 0x00526768 Worker 2042 Subdaemon 3220 0x0072e768 Flusher 2043 Subdaemon 3220 0x007348d0 Checkpoint 2044 Subdaemon 3220 0x067b0068 Aging 2045 Subdaemon 3220 0x067c0040 Monitor 2047 Subdaemon 3220 0x068404c8 HistGC 2046 Replication policy : Manual Replication agent is running. Cache agent policy : Manual ------------------------------------------------------------------------ Data store c:\temp\demo There are no connections to the data store Replication policy : Manual Cache agent policy : Manual ------------------------------------------------------------------------ End of report
Example 1-5 ttStatus shows cache group information
This example shows the cache agent running on rep1
data store. There is one cache group in the data store. The cache agent has five connections to the data store.
C:\>ttStatus TimesTen status report as of Mon Mar 19 10:47:46 2007 Daemon pid 1012 port 17000 instance MYINSTANCE No TimesTen server running TimesTen webserver pid 1708 started on port 17004 ---------------------------------------------------------------- Data store c:\data\rep1 There are 12 connections to the data store Data store is in shared mode Shared Memory KEY Global\DBI45ef98ac.1.SHM.56 HANDLE 0x260 Type PID Context Connection Name ConnID Cache Agent 3380 0x00bbddf0 Handler 2 Cache Agent 3380 0x00c3f318 Aging 3 Cache Agent 3380 0x07380398 Timer 4 Cache Agent 3380 0x073cfa18 ttora70 6 Cache Agent 3380 0x073ff010 ttora70 7 Process 2084 0x00c48ee8 rep1 1 Subdaemon 1632 0x006bc430 Worker 2042 Subdaemon 1632 0x06630458 Flusher 2045 Subdaemon 1632 0x0664f978 Checkpoint 2044 Subdaemon 1632 0x0665ee60 HistGC 2043 Subdaemon 1632 0x066de720 Aging 2046 Subdaemon 1632 0x0670dc78 Monitor 2047 Replication policy : Manual Cache agent policy : Manual TimesTen's Cache agent is running for this data store ----------------------------------------------------------------- End of report
Example 1-6 ttStatus shows connection to old instance
This example shows a connection to an old instance of a data store. This can occur when a data store is invalidated, but some users have not disconnected from the invalidated copy of the data store still in memory. After all users disconnect, the memory can be freed.
C:\>ttStatus TimesTen status report as of Thu Jan 25 16:44:49 2007 Daemon pid 5088 port 17000 instance MYINSTANCE TimesTen server pid 4344 started on port 17002 TimesTen webserver pid 4216 started on port 17004 ----------------------------------------------------------------- Data store c:\temp\sample There are no connections to the data store Obsolete or not yet active connection(s): Process 4696 context 0xd08800 name sample connid 1, obsolete connection, shmKey 'Global\DBI45b94c6f.3.SHM.4' Replication policy : Manual Cache agent policy : Manual ----------------------------------------------------------------- End of report
The ttCapture
utility captures information about the configuration and state of your TimesTen system into a file that provides Technical support with a snapshot of your system at the time the ttCapture
utility is running. The ttCapture
utility generates a file named ttcapture.
date.time.
log
. By default, the file is written to the directory from which you invoke the ttCapture
utility. Use the ttCapture
-dest
option to direct the output file to be written to another directory.
If you run ttCapture
again, it writes the information to a new file.
On Windows platforms, running ttCapture
also produces an XML file named ttcapture.
date.time
.nfo
that contains output from the msinfo32
utility.
When you experience a problem with a TimesTen data store, run ttCapture
with the DSN
option for the data store as soon as possible, either when you are encountering the problem or immediately afterward.
Note:
Always double-quote directory and file names in case there are spaces in the names.When you contact Technical support, upload the ttcapture.
date.number.
log
file to the Service Request. Windows users should also upload the ttcapture.
date.time
.nfo
file.
See "ttCapture" in the Oracle TimesTen In-Memory Database Reference for information about additional options.
TimesTen uses a TimesTen daemon to manage access to the data stores. As the daemon operates, it generates error, warning and informational messages. These messages may be useful for TimesTen system administration and for debugging applications.
By default, informational messages are stored in:
A user error log that contains information you may need to see. Generally, these messages contain information about actions you may need to take.
A support log containing everything in the user error log plus information for use by Technical support.
See "Modifying informational messages" in the Oracle TimesTen In-Memory Database Operations Guide for information about configuring the logs, including their location and size.
Use the ttTraceMon
utility to log various trace information on a number of TimesTen components. Each TimesTen component can be traced at different levels of detail. You can list all of the traceable TimesTen components and their current tracing level by specifying ttTraceMon
with the show
subcommand. The full list of options for ttTraceMon
is described in the Oracle TimesTen In-Memory Database Reference.
TimesTen tracing severely impacts application performance and consumes a great deal of disk space if trace output is directed to a file. In addition, when using AWT cache groups, you must restart the replication agent when trying to trace the ORACON component with ttTraceMon
. Use the ttTraceMon
utility only when diagnosing problems. When you are finished, reset tracing to the default values.
Example 1-7 Default trace levels for components
This example shows that the levels for most tracing components are set to level 0 (off) for the demo data store. ERR tracing is level 1 by default. See "ERR tracing".
% ttTraceMon -e show demo LATCH ... 0 LOCK ... 0 LOG ... 0 LOGF ... 0 TRACE ... 0 API ... 0 HEAP ... 0 SM ... 0 XACT ... 0 EE ... 0 CG ... 0 SQL ... 0 TEST ... 0 FLOW ... 0 PT ... 0 ERR ... 1 REPL ... 0 OPT ... 0 CKPT ... 0 XA ... 0 ORACON ... 0 AGING ... 0 AUTOREFRESH ... 0
The output for most TimesTen components is of interest only to Technical support. However, the output for the SQL, API, LOCK, ERR, AGING and AUTOREFRESH components may be useful to you when you are troubleshooting application problems.
The rest of this section includes the following topics:
Start a new trace by specifying ttTraceMon
datastore
. For example, to start a trace on the demo data store, enter:
% ttTraceMon demo Trace monitor; empty line to exit Trace >
At the Trace prompt, specify the type of trace and its level. For example, to start tracing the SQL component at level 3, enter:
Trace > level sql 3
At this point you can run your application and the TimesTen trace information is written to a trace buffer. There are two ways to read the contents of the trace buffer:
From the Trace prompt, use the outfile
command to direct the trace buffer data to a file. (You must do this before running your application.) When writing tracing information to a file, new trace information is concatenated to the existing contents of the file.
From the Trace prompt, use the dump
command to display the trace buffer data to your screen.
Note:
The contents of the trace buffer accumulate with each new trace. To clear the trace buffer, use theflush
command from a ttTraceMon
prompt. Clear the buffered trace records for a specific component by specifying the component with the flush
command.Each record from the trace buffer has the following format:
timestamp sequence component level connection processid operation
The fields in the records are defined as follows:
timestamp
is the time at which the operation was executed.
sequence
is the incremental number that identifies the trace line.
component
is the TimesTen component being traced (such as SQL, API, LOCK, or ERR).
level
is the trace level associated with the trace line. The range of trace levels differs by component, but for all components, the lowest trace level generates the least verbose output and highest trace level generates the most verbose output. For example, if you are tracing SQL at level 4, your output includes lines for levels 2 (prepare), 3 (execute), and 4 (open, close, fetch).
Note:
Trace levels for some components are not a continuous range of numbers. If you enter a number that does not correspond to a supported level for a component, tracing occurs at the highest supported level that is less than the number you entered. For example, if tracing levels for a component are 1, 2, 3, 4, and 6 and you enter 5, tracing events for level 1, 2, 3, and 4 are generated.connection
is the internal connection ID identifying the connection that generated the trace. This number corresponds to the ConnID shown in ttStatus
output. The connection ID is also used as the first element of the transaction ID.
processid
is the operating system process ID for the process that generated the trace.
operation
is the operation that occurred (such as SQL statement, API operation, or error message).
For example, a line from the trace buffer after a SQL trace at level 3 might look like this:
10:39:50.231 5281 SQL 2L 1C 3914P Preparing: select cust_num from customer
Using ttTraceMon
with the SQL component provides information about the SQL being prepared or executed by the TimesTen engine. Table 1-1 describes the levels for SQL tracing.
Table 1-1 SQL tracing levels
Level | Output |
---|---|
2 |
SQL commands being prepared. |
3 |
+ SQL commands being executed |
4 |
+ The effect of command pooling (prepares not being done because the prepared command already exists in the pool), the need for reprepares (for example, because an index was created), and commands being destroyed. At this level, |
5 |
+ Some internal data, such as command numbers, which are not generally useful for customer-level debugging. |
Note:
TimesTen recommends tracing SQL at level 3 or 4. SQL tracing does not show any information about the optimizer. Optimizer tracing is managed by a separate component (OPT) at level 4 only, and is not designed for customer use.Example 1-8 SQL trace
In this example, we execute ttTraceMon
to do a SQL trace at level 4 on the demo
data store. We direct the output from the SQL trace to the SQLtrace.txt
file. We then flush the buffer so that the trace does not report past SQL statements.
% ttTraceMon demo Trace monitor; empty line to exit Trace > outfile SQLtrace.txt Trace > level sql 4 Trace > flush
At this point, we execute an application that includes the following SQL statement:
SELECT * FROM departments WHERE department_id = 10;
The trace information is written to the SQLtrace.txt
file:
12:19:36.582 269 SQL 2L 3C 29570P Preparing: select * from departments where department_id = 10 12:19:36.583 270 SQL 4L 3C 29570P sbSqlCmdCompile ()(E): (Found already compiled version: refCount:01, bucket:28) cmdType:100, cmdNum:1000146. 12:19:36.583 271 SQL 4L 3C 29570P Opening: select * from departments where department_id = 10; 12:19:36.583 272 SQL 4L 3C 29570P Fetching: select * from departments where department_id = 10; 12:19:36.583 273 SQL 4L 3C 29570P Closing: select * from departments where department_id = 10; 5 records dumped
When the application has completed, we turn off SQL tracing and exit ttTraceMon
.
Trace > level sql 0 Trace > {press ENTER – blank line}
API traces are generated for database operations such as connecting to a data store, changing a connection attribute, and committing a transaction. Table 1-2 describes the levels for API tracing.
Table 1-2 API tracing levels
Level | Output |
---|---|
1 |
All rollback attempts by the subdaemon. This occurs if an application exits abruptly and the subdaemon recovers its connection. |
2 |
+ Some low-on-space conditions. |
3 |
+ Create, connect, disconnect, checkpoint, backup, and compact operations for the data store, as well as commit and rollback for each connection, and a few other operations. |
4 |
+ Most other operations conducted at TimesTen's internal API level. It does not show numerous operations on the storage manager and indexes that are done internally. |
Note:
TimesTen recommends tracing at level 3.Example 1-9 API trace
In this example, we execute ttTraceMon
to do a API trace at level 3 on the demo
data store. The output from the API trace is written to the APItrace.txt
file. Before saving the API trace to the buffer, we use the flush
command to empty the buffer.
% ttTraceMon demo Trace monitor; empty line to exit Trace> outfile APItrace.txt Trace> level api 3 Trace > flush
At this point, we execute the application. When the application has completed, we turn off API tracing and exit ttTraceMon
:
Trace > level api 0 Trace > {press ENTER – blank line}
The contents of APItrace.txt
are similar to the sample output shown below. The output shows connection to the data store, setting the connection character set, setting the isolation level, and committing a transaction.
11:54:26.796 1016 API 3L 2C 4848P sb_dbConnect()(X) 11:54:26.796 1017 API 3L 2C 4848P sb_dbConnCharsetSet()(E) 11:54:26.796 1018 API 3L 2C 4848P sb_dbConnSetIsoLevel()(E) 11:54:39.795 1019 API 3L 2C 4848P sb_dbConnSetIsoLevel()(E) 11:54:45.253 1020 API 3L 2C 4848P sb_xactCommitQ()(E)
Use the LOCK component to trace the locking behavior of your application to detect trouble with deadlocks or lock waits. LOCK tracing generates a great deal of volume, so it is important to choose the appropriate level of tracing. Level 3, for example, begins to generate a large number of traces, as traces are written for fairly common events. In addition, the traces themselves may be somewhat hard to read in places. If you cannot discern enough information for your purposes, contact Technical support for more information.
Table 1-3 describes the LOCK tracing levels.
Table 1-3 LOCK tracing levels
Level | Output |
---|---|
1 |
Deadlock cycles as they are discovered. |
2 |
+ Failures to grant locks for any reason. |
3 |
+ Lock waits (which may or may not be granted). |
4 |
+ All lock grants/releases, some routine calls, and the mechanism of the deadlock detector. |
6 |
+ Each step in cycle traversal. |
Example 1-10 LOCK trace
In this example, we execute ttTraceMon
to do a LOCK trace at level 4 on myDSN
data store.
We make two connections to myDSN
. For the first connection, we set autocommit on. We create table test
and insert three rows. We create a materialized view using table test
.
We turn on tracing at level 4 and use the flush
command to empty the buffer.
% ttTraceMon myDSN Trace monitor; empty line to exit Trace> level lock 4 Trace> flush
For the second connection to myDSN
, we set autocommit off. We insert a row into table test. Because autocommit is off, the row is not inserted into the table until we commit. A lock is held until we commit or roll back the transaction.
If we use the dump
command to display the contents of the trace buffer, we see that there are no records in the trace buffer:
Trace> dump 0 records dumped
From the first connection, we try to drop the materialized view. We cannot drop the view because there is a transaction that has not been committed or rolled back:
Command> drop materialized view v; 6003: Lock request denied because of time-out Details: Tran 3.71 (pid 24524) wants Sn lock on table TTUSER.TEST. But tran 1.42 (pid 24263) has it in IXn (request was IXn). Holder SQL (insert into test values (100);) The command failed.
The trace buffer contains the following information:
Trace> dump 20:09:04.789 174759 LOCK 3L 3C 24524P ENQ: xcb:00003 <Tbl 0x9b894,0x0> 0+Sn=>SL activity 0 Sn cnt=0; Holder xcb:00001 IXn 20:09:04.789 174760 LOCK 3L 3C 24524P Connection 3 scheduled for sleep 20:09:04.789 174761 LOCK 3L 3C 24524P Connection 3 sleeping 20:09:14.871 174762 LOCK 3L 2047C 24237P Connection 3 timed out 20:09:14.871 174763 LOCK 3L 2047C 24237P Connection 3 woken up 20:09:14.871 174764 LOCK 3L 3C 24524P Connection 3 awake 20:09:14.871 174765 LOCK 2L 3C 24524P ENQ: xcb:00003 <Tbl 0x9b894,0x0> 0+Sn=>TM activity 0 Sn cnt=1; Holder xcb:00001 IXn 7 records dumped
When finished with the trace, we set LOCK tracing back to its default setting (0) and exit ttTraceMon
:
Trace > level lock 0 Trace > {press ENTER – blank line}
It may be useful to trace the ERR component. For example, an ERR trace at level 4 shows all of the error messages that are pushed in the TimesTen direct driver (not all errors are output to the user because they are handled internally). ERR tracing at level 1 is the default. No output is written for ERR tracing at level 2 and 3.
Table 1-4 describes ERR tracing levels.
Table 1-4 ERR tracing levels
Level | Output |
---|---|
1 (set by default) |
Fatal errors |
4 |
+ All other error messages, many of which are handled internally by TimesTen. |
Example 1-11 ERR trace
In this example, we execute ttTraceMon
to do a ERR trace at level 4 on myDSN
data store.
First we create a table:
Command> create table test (id tt_integer);
Next we turn on tracing at level 4. Rather than direct the trace output to a file as in the previous examples, we read it directly from the trace buffer. Before saving the ERR trace to the buffer, we use the flush
command to empty the buffer.
% ttTraceMon myDSN Trace monitor; empty line to exit Trace> level err 4 Trace> flush
Now we execute a SQL script with three errors in it. The errors are:
Creating a table with the same name as an existing table
Using incorrect syntax to insert values into the table
Inserting CHAR data into a TT_INTEGER column
Command> create table test (id tt_integer); 2207: Table TEST already exists The command failed. Command> insert into test values 'abcd'); 1001: Syntax error in SQL statement before or at: "'abcd'", character position: 25 insert into test values 'abcd'); ^^^^^^ The command failed. Command> insert into test values ('abcd'); 2609: Incompatible types found in expression The command failed.
The trace information is written to the trace buffer. We display it by using the dump
command.
Trace> dump 19:28:40.465 174227 ERR 4L 1C 24263P TT2207: Table TEST already exists -- file "eeDDL.c", lineno 2930, procedure "sbEeCrDtblEval()" 19:28:51.399 174228 ERR 4L 1C 24263P TT1001: Syntax error in SQL statement before or at: "'abcd'", character position: 25 insert into test values 'abcd'); ^^^^^^ -- file "ptSqlY.y", lineno 6273, procedure "reserved_word_or_syntax_error" 19:29:00.725 174229 ERR 4L 1C 24263P TT2609: Incompatible types found in expression -- file "saCanon.c", lineno 12618, procedure "sbPtAdjustType()" 3 records dumped
Set ERR tracing back to its default setting (1) and exit ttTraceMon
:
Trace > level err 1 Trace > {press ENTER – blank line}
Use the ttTraceMon
utility to obtain the following information:
When aging starts and ends
How many rows have been deleted by the aging subdaemon
See "Implementing aging in your tables" in the Oracle TimesTen In-Memory Database Operations Guide.
Table 1-5 describes the AGING tracing levels.
Table 1-5 AGING tracing levels
Level | Description |
---|---|
1 |
Displays messages about the following events:
|
2 |
+Displays messages about the following events for each table:
|
3 |
+Detailed report on how many rows were deleted during each aging cycle. |
4 |
+Message every time the aging subdaemon wakes up. |
Example 1-12 AGING trace
In this example, we execute ttTraceMon
to do an AGING trace on myDSN
data store. The data store contains TTUSER.MYTAB
table, which has a time-based aging policy. The table is described as follows:
Command> describe TTUSER.MYTAB; Table TTUSER.MYTAB: Columns: *ID TT_INTEGER NOT NULL TS TIMESTAMP (6) NOT NULL Aging use TS lifetime 3 minutes cycle 1 minute on 1 table found. (primary key columns are indicated with *)
The table contains the following rows before the aging cycle begins:
Command> select * from TTUSER.MYTAB; < 1, 2007-03-21 12:54:06.000000 > < 3, 2010-03-17 08:00:00.000000 > < 4, 2007-03-21 12:59:40.000000 > < 5, 2007-03-21 13:00:10.000000 > < 6, 2007-03-21 13:01:22.000000 > 5 rows found.
We execute ttTraceMon
to do an AGING trace at level 3. Rather than direct the trace output to a file, we read it directly from the trace buffer. Before saving the AGING trace to the buffer, we use the flush
command to empty the buffer.
% ttTraceMon myDSN Trace monitor; empty line to exit Trace> level aging 3 Trace> flush
Display the trace information in the buffer by using the dump
command.
Trace> dump 13:16:56.802 1247 AGING 1L 2045C 17373P Entering sbAgingTB(): curTime=78 13:16:56.803 1248 AGING 2L 2045C 17373P Entering sbAgingOneTable(): curTime=78, ltblid= 637140 13:16:56.804 1249 AGING 3L 2045C 17373P curTime=78, 4 deleted, 1 remaining, tbl = TTUSER.MYTAB 13:16:56.804 1250 AGING 2L 2045C 17373P Exiting sbAgingOneTable(): curTime=78, reason = 'no more rows', 4 deleted, 1 remaining, tbl = TTUSER.MYTAB 13:16:56.804 1251 AGING 1L 2045C 17373P Exiting sbAgingTB(): curTime=78 5 records dumped
We set AGING tracing back to its default setting (0) and exit ttTraceMon
:
Trace > level aging 0 Trace > {press ENTER – blank line}
Use the ttTraceMon
utility to obtain information about the progress of autorefresh operations for cache groups with the AUTOREFRESH cache group attribute.
See "AUTOREFRESH cache group attribute" in the Oracle In-Memory Database Cache User's Guide.
Table 1-6 describes AUTOREFRESH tracing levels.
Table 1-6 AUTOREFRESH tracing levels
Level | Description |
---|---|
1 |
Autorefresh summary for the interval:
Note: Times and information about root table rows are reported for full autorefresh. |
2 |
+Autorefresh summary at the cache group level:
Note: Times and information about root table rows are reported for full autorefresh. |
3 |
+Autorefresh summary at the table level:
|
4 |
+Autorefresh details for each table:
|
Example 1-13 AUTOREFRESH trace
In this example, we use the ttTraceMon
utility to trace autorefresh operations on the cgDSN
data store. When we set the trace level to 1, we see information that is similar to the output of the ttCacheAutorefreshStatsGet
built-in procedure.
% tttracemon cgDSN Trace monitor; empty line to exit Trace> level autorefresh 1 Trace> dump 08:56:57.445 19398 AUTOREFRESH 1L 5C 32246P Autorefresh number 1415 started for interval 60000 08:56:57.883 19419 AUTOREFRESH 1L 5C 32246P Duration For Interval 60000ms: 420 08:56:57.883 19420 AUTOREFRESH 1L 5C 32246P Num Rows For Interval 60000ms: 0 08:56:57.883 19421 AUTOREFRESH 1L 5C 32246P Num Root Rows For Interval 60000ms: 0 08:56:57.883 19422 AUTOREFRESH 1L 5C 32246P Cumulative Rows for Interval 60000ms: 11587 08:56:57.883 19423 AUTOREFRESH 1L 5C 32246P Cumulative Root Rows for Interval 60000ms: 1697 08:56:57.883 19424 AUTOREFRESH 1L 5C 32246P Autorefresh number 1415 ended for interval 60000ms successfully. 7 records dumped
Tracing at level 4 produces additional information about autorefresh operation 1415. Information about autorefresh is provided for the testuser.readcache
cache group, the testuser.readtab
root table and the autorefresh interval.
Trace> level autorefresh 4 Trace> dump 08:56:57.445 19398 AUTOREFRESH 1L 5C 32246P Autorefresh number 1415 started for interval 60000 08:56:57.471 19399 AUTOREFRESH 2L 5C 32246P Autorefresh started for cachegroup TESTUSER.READCACHE 08:56:57.471 19400 AUTOREFRESH 3L 5C 32246P Incremental autorefresh started for table TESTUSER.READTAB 08:56:57.471 19401 AUTOREFRESH 4L 5C 32246P Autorefresh Query: SELECT L."COL_10", X."COL_20", X.ft$NotDelete, Z.rowid FROM (SELECT DISTINCT "COL_10" FROM "TESTUSER"."TT_03_454854_L" WHERE logseq >:logseq AND ft_cacheGroup <> 100000000000*1844259679+-299200618) L,(SELECT "TESTUSER"."READTAB"."COL_10", "TESTUSER"."READTAB"."COL_20", 1 AS ft$NotDelete FROM "TESTUSER"."READTAB", "TESTUSER"."T1" WHERE "TESTUSER"."READTAB"."COL_10" = "TESTUSER"."T1"."COL_10") X, "TESTUSER"."READTAB" Z WHERE L ."COL_10" = X."COL_10" (+) AND X."COL_10" = Z."COL_10" (+), logseq: 7 08:56:57.870 19402 AUTOREFRESH 3L 5C 32246P Duration for table TESTUSER.READTAB: 70 08:56:57.870 19403 AUTOREFRESH 3L 5C 32246P Num Rows for table TESTUSER.READTAB: 1 08:56:57.870 19404 AUTOREFRESH 3L 5C 32246P Cumulative rows for table TESTUSER.READTAB: 1559 08:56:57.870 19405 AUTOREFRESH 4L 5C 32246P Autorefresh Query Execute duration for table TESTUSER.READTAB: 60 08:56:57.870 19406 AUTOREFRESH 4L 5C 32246P Autorefresh Query Fetch duration for table TESTUSER.READTAB: 0 08:56:57.870 19407 AUTOREFRESH 4L 5C 32246P Autorefresh Query Apply duration for table TESTUSER.READTAB: 0 08:56:57.870 19408 AUTOREFRESH 4L 5C 32246P Max logseq applied for table TESTUSER.READTAB: 8 08:56:57.870 19409 AUTOREFRESH 4L 5C 32246P Autorefresh Query Execute duration for 7 child(ren) table(s): 32 08:56:57.870 19410 AUTOREFRESH 4L 5C 32246P Autorefresh Query Fetch duration for 7 child(ren) table(s): 0 08:56:57.870 19411 AUTOREFRESH 4L 5C 32246P Autorefresh Query Apply duration for 7 child(ren) table(s): 0 08:56:57.870 19412 AUTOREFRESH 3L 5C 32246P Incremental autorefresh ended for table TESTUSER.READTAB 08:56:57.872 19413 AUTOREFRESH 2L 5C 32246P Duration For Cache Group TESTUSER.READCACHE: 1020 08:56:57.872 19414 AUTOREFRESH 2L 5C 32246P Num Rows For Cache Group TESTUSER.READCACHE: 1 08:56:57.872 19415 AUTOREFRESH 2L 5C 32246P Num Root Rows For Cache Group TESTUSER.READCACHE: 0 08:56:57.872 19416 AUTOREFRESH 2L 5C 32246P Cumulative Rows for Cache Group TESTUSER.READCACHE: 11776 08:56:57.872 19417 AUTOREFRESH 2L 5C 32246P Cumulative Root Rows for Cache Group TESTUSER.READCACHE: 1697 08:56:57.872 19418 AUTOREFRESH 2L 5C 32246P Autorefresh ended for cache group TESTUSER.READCACHE 08:56:57.883 19419 AUTOREFRESH 1L 5C 32246P Duration For Interval 60000ms: 420 08:56:57.883 19420 AUTOREFRESH 1L 5C 32246P Num Rows For Interval 60000ms: 0 08:56:57.883 19421 AUTOREFRESH 1L 5C 32246P Num Root Rows For Interval 60000ms: 0 08:56:57.883 19422 AUTOREFRESH 1L 5C 32246P Cumulative Rows for Interval 60000ms: 11587 08:56:57.883 19423 AUTOREFRESH 1L 5C 32246P Cumulative Root Rows for Interval 60000ms: 1697 08:56:57.883 19424 AUTOREFRESH 1L 5C 32246P Autorefresh number 1415 ended for interval 60000ms successfully. 27 records dumped
We set AUTOREFRESH tracing back to its default setting (0) and exit ttTraceMon
:
Trace > level autorefresh 0 Trace > {press ENTER – blank line}
The ttXactAdmin
utility displays ownership, status, log and lock information for each outstanding transaction. You can also use it to show all current connections to a data store. The ttXactAdmin
utilty is useful for troubleshooting problems with replication, XLA, and asynchronous writethrough cache groups.
Example 1-14 Using ttXactAdmin to diagnose a lock timeout
Use ttXactAdmin
to diagnose a lock timeout. Consider two connections that are trying to update the same row. The following transaction by Connection 1 is in progress:
UPDATE table1 SET c1 = 2 WHERE c1 = 1;
Connection 2 attempts to make the following update:
UPDATE table1 SET c1 = 3 WHERE c1 = 1;
Connection 2 receives the following error:
6003: Lock request denied because of time-out Details: Tran 2.3 (pid 2880) wants Un lock on rowid 0x00156bbc, table TTUSER.TABLE1. But tran 1.21 (pid 2564) has it in Xn (request was Xn). Holder SQL (update table1 set c1 = 2 where c1 = 1;) The command failed.
The details of the error indicate that transaction 1.21 has a lock on row 0x00156bbc, the row that transaction 2.3 wants to update. ttXactAdmin
displays this information in output that pertains to actions in the entire data store:
$ ttXactAdmin myDSN 2007-03-23 11:26:01.643 c:\datastore\myDSN TimesTen Release 7.0.2.0.0 Outstanding locks PID Context TransID TransStatus Resource ResourceID Mode Name Program File Name: ttIsql 2564 0xeeb9a8 1.21 Active Database 0x01312d00 IX Row 0x00156bbc Xn TTUSER.TABLE1 Table 1910868 IXn TTUSER.TABLE1 Program File Name: ttIsql 2880 0xeeb9a8 2.3 Active Database 0x01312d00 IX Table 1910868 IXn TTUSER.TABLE1 Command 19972120 S Awaiting locks PID Context TransID Resource ResourceID RMode HolderTransID HMode Name 2880 0xeeb9a8 2.3 Row 0x00156bbc Un 1.21 Xn TTUSER.TABLE1 2 outstanding transactions found
See "ttXactAdmin" in the Oracle TimesTen In-Memory Database Reference.
On Windows, use the ODBC trace facility to verify the sequence and content of your commands. The ODBC trace facility works only if you have linked your application with the ODBC Driver Manager. Enable tracing by double-clicking ODBC in the Control Panel. This opens the ODBC Data Source Administrator. Choose the Tracing tab.
On UNIX platforms, ODBC tracing is available only when using a driver manager. To turn on tracing, set the Trace and TraceFile attributes.
Network management software uses SNMP (Simple Network Management Protocol) to query or control the state of network devices such as routers and switches. These devices can generate alerts called traps to inform the network management systems of problems.
TimesTen sends SNMP traps for particular critical events to help facilitate user recovery mechanisms. These events are also recorded in the support log. Exposing them through SNMP traps allows network management software to take immediate action.
How to configure TimesTen to generate SNMP traps as well as how to receive the traps is described in "Diagnostics through SNMP Traps" in the Oracle TimesTen In-Memory Database Error Messages and SNMP Traps.
To understand how network software might be used to detect SNMP traps, use the snmptrapd
program provided in your TimesTen directory: /
install_dir
/demo/snmp
. This demo listens on a designated port for SNMP trap messages and either prints the traps to stdout
or logs them to syslogd
. See the /
install_dir
/demo/snmp/README.txt
file for details.
Each TimesTen data store contains a group of system tables that store metadata about the current state of the data store. The system tables are described in "System and Replication Tables" in the Oracle TimesTen In-Memory Database Error Messages and SNMP Traps.
Note:
You can execute SELECT statements on a system table, but you cannot execute a statement such as INSERT, UPDATE or DELETE on these tables.Of particular interest when troubleshooting is the SYS.MONITOR table, which contains statistics about certain events that have occurred since the first connection to the data store. For example, the SYS.MONITOR table contains information about the number of connections to the data store; the number of checkpoints taken; the size of the data store; and the amount of memory currently in use. Check the contents of the SYS.MONITOR table by executing SELECT statements on the columns or by using the ttIsql
monitor
command. For an example of how to use the ttIsql
monitor
command, see "Using the ttIsql Utility" in the Oracle TimesTen In-Memory Database Operations Guide.
The SYS.MONITOR table is useful for troubleshooting performance problems. See "Reading the PLAN table" in the Oracle TimesTen In-Memory Database Operations Guide for details. Check the contents of the SYS.MONITOR table by executing SELECT statements on the columns or by using the ttIsql
showplan
command, as described in "Viewing and changing query optimizer plans" in the Oracle TimesTen In-Memory Database Operations Guide.
The query optimizer is an important tool for performance tuning.
For details about using the query optimizer, see:
"The TimesTen Query Optimizer" in the Oracle TimesTen In-Memory Database Operations Guide
"Viewing and changing query optimizer plans" in the Oracle TimesTen In-Memory Database Operations Guide
If you find that a given query runs more slowly than expected, confirm that the query optimizer has the latest statistics for the tables in your query, as described in "Update query optimizer statistics". If, after updating your statistics, your query still runs too slowly, it is possible that the TimesTen optimizer is not choosing the optimal query plan to answer that query. Under these circumstances, you can adjust how the optimizer generates a plan by using the ttOpt
* procedures described in "Modifying plan generation" in the Oracle TimesTen In-Memory Database Operations Guide.