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• String manipulation functions in SQL Server 2000 / 2005

  - by Vipin

  SQL Server provides a range of string manipulation functions. I was aware of most of those in back of the mind, but when I needed to use one, I had to dig it out either from SQL server help file or from google. So, I thought I will list some of the functions which performs some common operations in SQL server. Hope it will be helpful to you all. Len (' String_Expression' ) - returns the length of input String_Expression. Example - Select Len('Vipin') Output - 5 Left ( 'String_Expression', int_characters ) - returns int_characters characters from the left of the String_Expression.     Example - Select Left('Vipin',3), Right('Vipin',3) Output -  Vip,  Pin  LTrim ( 'String_Expression' ) - removes spaces from left of the input 'String_Expression'  RTrim ( 'String_Expression' ) - removes spaces from right of the input 'String_Expression' Note - To removes spaces from both ends of the string_expression use Ltrim and RTrim in conjunction Example - Select LTrim(' Vipin '), RTrim(' Vipin ') , LTrim ( RTrim(' Vipin ')) Output - 'Vipin ' , ' Vipin' , 'Vipin' (Single quote marks ' ' are not part of the SQL output, it's just been included to demonstrate the presence of space at the end of string.) Substring ( 'String_Expression' , int_start , int_length ) - this function returns the part of string_expression. Right ( 'String_Expression', int_characters ) - returns int_characters characters from the right of the String_Expression.

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• TechEd 2012: Fast SQL Server

  - by Tim Murphy

  While I spend a certain amount of my time creating databases (coding around SQL Server and setup a server when I have to) it isn’t my bread and butter.  Since I have run into a number of time that SQL Server needed to be tuned I figured I would step out of my comfort zone and see what I can learn. Brent Ozar packed a mountain of information into his session on making SQL Server faster.  I’m not sure how he found time to hit all of his points since he was allowing the audience abuse him on Twitter instead of asking questions, but he managed it.  I also questioned his sanity since he appeared to be using a fruit laptop. He had my attention though when he stated that he had given up on telling people to not use “select *”. He posited that it could be fixed with hardware by caching the data in memory.  He continued by cautioning that having too many indexes could defeat this approach.  His logic was sound if not always practical, but it was a good place to start when determining the trade-offs you need to balance.  He was moving pretty fast, but I believe he was prescribing this solution predominately for OLTP database prior to moving on to data warehouse solutions. Much of the advice he gave for data warehouses is contained in the Microsoft Fast Track guidance so I won’t rehash it here.  To summarize the solution seems to be the proper balance memory, disk access speed and the speed of the pipes that get the data from storage to the CPU.  It appears to be sound guidance and the session gave enough information that going forward we should be able to find the details needed easily.  Just what the doctor ordered. del.icio.us Tags: SQL Server,TechEd,TechEd 2012,Database,Performance Tuning

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• SQL queries break our game! (Back-end server is at capacity)

  - by TimH

  We have a Facebook game that stores all persistent data in a MySQL database that is running on a large Amazon RDS instance. One of our tables is 2GB in size. If I run any queries on that table that take more than a couple of seconds, any SQL actions performed by our game will fail with the error: HTTP/1.1 503 Service Unavailable: Back-end server is at capacity This obviously brings down our game! I've monitored CPU usage on the RDS instance during these periods, and though it does spike, it doesn't go much over 50%. Previously we were on a smaller instance size and it did hit 100%, so I'd hoped just throwing more CPU capacity at the problem would solve it. I now think it's an issue with the number of open connections. However, I've only been working with SQL for 8 months or so, so I'm no expert on MySQL configuration. Is there perhaps some configuration setting I can change to prevent these queries from overloading the server, or should I just not be running them whilst our game is up? I'm using MySQL Workbench to run the queries. Here's an example.... SELECT * FROM BlueBoxEngineDB.Transfer WHERE Amount = 1000 AND FromUserId = 4 AND Status='Complete'; As you can see, it's not overly complex. There are only 5 columns in the table. Any help would be very much appreciated - Thanks!

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• SQL Server Configuration Scripting Utility Release 9

  - by Bill Graziano

  There’s another update to my little utility to script a SQL Server’s configuration.  I use this for two purposes.  First, I use it to keep my database mirroring servers up to date.  Second, I capture the output in a version control system and keep that for historical reference. In release 3.0.9 I made the following changes: Rewrote the encrypted trigger scripting.  It will now list the encrypted triggers in a comment in the table script but can’t actually script them. It now scripts any server event notifications. You can script a single database using the /scriptdb flag.  Please note that it will also script the instance and system databases when it does this. It will script any user-defined endpoints.  This will capture your mirroring endpoints and more importantly any service broker endpoints. It will gracefully skip database mail on the Express Edition. It still doesn’t support SQL Server 2012.  I think that’s the next feature to add though.

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• SQL Server 2005 Disk Configuration: Single RAID 1+0 or multiple RAID 1+0s?

  - by mfredrickson

  Assuming that the workload for the SQL Server is just a normal OLTP database, and that there are a total of 20 disks available, which configuration would make more sense? A single RAID 1+0, containing all 20 disks. This physical volume would contain both the data files and the transaction log files, but two logical drives would be created from this RAID: one for the data files and one for the log files. Or... Two RAID 1+0s, each containing 10 disks. One physical volume would contain the data files, and the other would contain the log files. The reason for this question is due to a disagreement between me (SQL Developer) and a co-worker (DBA). For every configuration that I've done, or seen others do, the data files and transaction log files were separated at the physical level, and were placed on separate RAIDs. However, my co-workers argument is that by placing all the disks into a single RAID 1+0, then any IO that is done by the server is potentially shared between all 20 disks, instead of just 10 disks in my suggested configuration. Conceptually, his argument makes sense to me. Also, I've found some information from Microsoft that seems to supports his position. http://technet.microsoft.com/en-us/library/cc966414.aspx In the section titled "3. RAID10 Configuration", showing a configuration in which all 20 disks are allocated to a single RAID 1+0, it states: In this scenario, the I/O parallelism can be used to its fullest by all partitions. Therefore, distribution of I/O workload is among 20 physical spindles instead of four at the partition level. But... every other configuration I've seen suggests physically separating the data and log files onto separate RAIDs. Everything I've found here on Server Fault suggests the same. I understand that a log files will be write heavy, and that data files will be a combination of reads and writes, but does this require that the files be placed onto separate RAIDs instead of a single RAID?

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• Do you have a data roadmap?

  - by BuckWoody

  I often visit companies where they asked me “What is SQL Server’s Roadmap?” What they mean is that they want to know where Microsoft is going with our database products. I explain that we’re expanding not only the capacities in SQL Server but the capabilities – we’re trying to make an “information platform”, rather than just a data store. But it’s interesting when I ask the same question back. “What is your data roadmap?” Most folks are surprised by the question, thinking only about storage and archival. To them, data is data. Ah, not so. Your data is one of the most valuable, if not the most valuable asset in your organization. And you should be thinking about how you’ll acquire it, how it will be distributed, how you’ll archive it (which includes more than just backing it up) and most importantly, how you’ll leverage it. Because it’s only when data becomes information that it is truly useful. to be sure, the folks on the web that collect lots of data have a strategy for it – do you? Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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• SQL Health Check...... ?????????

  - by Steve He(???)

  ??????,??????????,???????????????,????SQL?????,????????????????,????????????????????????????,???????????????????????????????????? ???,????SQLHC,??????SQL??????????,????????(CBO)???,????????,???????????????????Document 1455583.1 ??? SQL Tuning Health-Check ??(SQLHC)???,??????????SQL??????,???????????????SQL????? ???????Recording???SQLHC?????? ????????????,???: SQL Tuning Health-Check Script (SQLHC) (Doc ID 1366133.1) Document 1417774.1 FAQ: SQLHC HealthCheck ??????

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• ??OPEN CURSOR?BULK COLLECT

  - by Liu Maclean(???)

  ????T.askmaclean.com?????bulk collect?open cursor???, ?????????  ??????: ???? OPEN_CURSOR ????SQL?? ???????. ?????? ????? ???????????????? ????? test_soruce create table zengfankun_temp01 as select * from dba_objects;select count(*) from zengfankun_temp01;–12,6826analyze table zengfankun_temp01 compute statistics; create or replace procedure test_open_cursor istype type_owner is table of zengfankun_temp01.owner%type index by binary_integer;type type_object_name is table of zengfankun_temp01.object_name%type index by binary_integer;type type_object_id is table of zengfankun_temp01.object_id%type index by binary_integer;type type_object_type is table of zengfankun_temp01.object_type%type index by binary_integer;type type_last_ddl_time is table of zengfankun_temp01.last_ddl_time%type index by binary_integer; l_ary_owner type_owner;l_ary_object_name type_object_name;l_ary_object_id type_object_id;l_ary_object_type type_object_type;l_ary_last_ddl_time type_last_ddl_time; cursor cur_object isselect owner,object_name,object_id,object_type,last_ddl_timefrom zengfankun_temp01order by owner,object_name,object_type,last_ddl_time;OPEN_START number;OPEN_END number;FETCH_START number;FETCH_END number;beginDBMS_OUTPUT.ENABLE (buffer_size=>null) ;OPEN_START:=dbms_utility.get_time();open cur_object;OPEN_END :=dbms_utility.get_time();dbms_output.put_line(‘OPEN_TIME:’||TO_CHAR(OPEN_END-OPEN_START));loopFETCH_START:=dbms_utility.get_time();fetch cur_object bulk collect intol_ary_owner,l_ary_object_name,l_ary_object_id,l_ary_object_type,l_ary_last_ddl_timelimit 10000;FETCH_END:=dbms_utility.get_time();dbms_output.put_line(‘FETCH_TIME:’||TO_CHAR(FETCH_END-FETCH_START)||’ ROWCOUNT:’||cur_object%rowCount); exit when cur_object%notfound or cur_object%notfound is null;end loop;end test_open_cursor; OPEN_TIME:12FETCH_TIME:21 ROWCOUNT:10000FETCH_TIME:3 ROWCOUNT:20000FETCH_TIME:3 ROWCOUNT:30000FETCH_TIME:3 ROWCOUNT:40000FETCH_TIME:3 ROWCOUNT:50000FETCH_TIME:3 ROWCOUNT:60000FETCH_TIME:3 ROWCOUNT:70000FETCH_TIME:3 ROWCOUNT:80000FETCH_TIME:3 ROWCOUNT:90000FETCH_TIME:3 ROWCOUNT:100000FETCH_TIME:3 ROWCOUNT:110000FETCH_TIME:3 ROWCOUNT:120000FETCH_TIME:1 ROWCOUNT:126826 ???? OPEN_TIME:0FETCH_TIME:18 ROWCOUNT:10000FETCH_TIME:3 ROWCOUNT:20000FETCH_TIME:3 ROWCOUNT:30000FETCH_TIME:3 ROWCOUNT:40000FETCH_TIME:3 ROWCOUNT:50000FETCH_TIME:3 ROWCOUNT:60000FETCH_TIME:3 ROWCOUNT:70000FETCH_TIME:3 ROWCOUNT:80000FETCH_TIME:3 ROWCOUNT:90000FETCH_TIME:3 ROWCOUNT:100000FETCH_TIME:3 ROWCOUNT:110000FETCH_TIME:3 ROWCOUNT:120000FETCH_TIME:2 ROWCOUNT:126826 SQL?????????, ????????????.??OPEN CURSOR ????0???????????3??.??N? ??????. ???? ?N? ?????????? ??????. ??????????????? ??????????. ?????????10000??? ???????????????????clear???, ???????????: ?OPEN CURSOR ?????, PL/SQL????SQL????PARSE SQL????????, ??????OPEN CURSOR????SNAPSHOT SCN ??SCN, ??Oracle?????FETCH?????,???????????????? ????FETCH ??????????????,???????Current Block, The most recent version of block , ?????SCN >> Snapshot scn, ????UNDO???? ???SCN ???Best Block ,???Read Consistentcy;???? ???UNDO SNAPSHOT???????????????Best Block??,???????ORA-1555??? ????????, ??????????,???????????????char(2000)????, ???????????????,????bulk collect fetch??fetch 10 ???,????????OPEN CURSOR?????PARSE??SQL????????, ??????????fetch bulk collect??????????10????,??”_trace_pin_time”????Server Process?pin CR block???,??????????Fetch Bulk Collect limit 10??10?buffer?pin? [oracle@nas ~]$ sqlplus / as sysdba SQL*Plus: Release 11.2.0.3.0 Production on Wed Aug 1 11:36:52 2012 Copyright (c) 1982, 2011, Oracle. All rights reserved. Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production With the Partitioning, OLAP, Data Mining and Real Application Testing options SQL> select * from global_name; GLOBAL_NAME -------------------------------------------------------------------------------- http://www.askmaclean.com SQL> create table maclean (t1 char(2000)) tablespace users pctfree 99; Table created. SQL> begin 2 for i in 1..200 loop 3 insert into maclean values('MACLEAN'); 4 commit ; 5 end loop; 6 end; 7 / PL/SQL procedure successfully completed. SQL> exec dbms_stats.gather_table_stats('','MACLEAN'); PL/SQL procedure successfully completed. SQL> select count(*) from maclean; COUNT(*) ---------- 200 SQL> select blocks,num_rows from dba_tables where table_name='MACLEAN'; BLOCKS NUM_ROWS ---------- ---------- 244 200 SQL> alter system set "_trace_pin_time"=1 scope=spfile; System altered. SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. SQL> alter session set events '10046 trace name context forever,level 12'; Session altered. SQL> SQL> SQL> declare 2 cursor v_cursor is 3 select * from sys.maclean; 4 type v_type is table of sys.maclean%rowtype index by binary_integer; 5 rec_tab v_type; 6 begin 7 open v_cursor; 8 dbms_lock.sleep(30); 9 loop 10 fetch v_cursor bulk collect 11 into rec_tab limit 10; 12 dbms_lock.sleep(10); 13 exit when v_cursor%notfound; 14 end loop; 15 end; 16 / ?????10046 trace+ pin trace: PARSING IN CURSOR #47499559136872 len=337 dep=0 uid=0 oct=47 lid=0 tim=1343836146412056 hv=496860239 ad='11a11dbb0' sqlid='4zh7954ftuz2g' declare cursor v_cursor is select * from sys.maclean; type v_type is table of sys.maclean%rowtype index by binary_integer; rec_tab v_type; begin open v_cursor; dbms_lock.sleep(30); loop fetch v_cursor bulk collect into rec_tab limit 10; dbms_lock.sleep(10); exit when v_cursor%notfound; end loop; end; END OF STMT PARSE #47499559136872:c=0,e=346,p=0,cr=0,cu=0,mis=0,r=0,dep=0,og=1,plh=0,tim=1343836146412051 ===================== PARSING IN CURSOR #47499559126280 len=25 dep=1 uid=0 oct=3 lid=0 tim=1343836146414939 hv=3296884535 ad='11a11d250' sqlid='2mb1493284xtr' SELECT * FROM SYS.MACLEAN END OF STMT PARSE #47499559126280:c=1999,e=2427,p=0,cr=0,cu=0,mis=1,r=0,dep=1,og=1,plh=2568761675,tim=1343836146414937 EXEC #47499559126280:c=0,e=55,p=0,cr=0,cu=0,mis=0,r=0,dep=1,og=1,plh=2568761675,tim=1343836146415104 ????? ? SELECT * FROM SYS.MACLEAN? PARSE ????? , ????FETCH???????pin ????????, ????OPEN CURSOR????? *** 2012-08-01 11:49:36.424 WAIT #47499559136872: nam='PL/SQL lock timer' ela= 30009361 duration=0 p2=0 p3=0 obj#=-1 tim=1343836176424782 ???30s pin ktewh26: kteinpscan dba 0x10a6202:4 time 1039048805 pin ktewh27: kteinmap dba 0x10a6202:4 time 1039048847 pin kdswh11: kdst_fetch dba 0x10a6203:1 time 1039048898 pin kdswh11: kdst_fetch dba 0x10a6204:1 time 1039048961 pin kdswh11: kdst_fetch dba 0x10a6205:1 time 1039049004 pin kdswh11: kdst_fetch dba 0x10a6206:1 time 1039049042 pin kdswh11: kdst_fetch dba 0x10a6207:1 time 1039049089 pin kdswh11: kdst_fetch dba 0x10a6208:1 time 1039049123 pin kdswh11: kdst_fetch dba 0x10a6209:1 time 1039049159 pin kdswh11: kdst_fetch dba 0x10a620a:1 time 1039049191 pin kdswh11: kdst_fetch dba 0x10a620b:1 time 1039049225 pin kdswh11: kdst_fetch dba 0x10a620c:1 time 1039049260 kdst_fetch???fetch??????? , ??fetch?10?? ???????FETCH FETCH #47499559126280:c=0,e=536,p=0,cr=12,cu=0,mis=0,r=10,dep=1,og=1,plh=2568761675,tim=1343836176425542 *** 2012-08-01 11:49:46.428 WAIT #47499559136872: nam='PL/SQL lock timer' ela= 10002694 duration=0 p2=0 p3=0 obj#=-1 tim=134383618642829 ????10s pin kdswh11: kdst_fetch dba 0x10a620d:1 time 1049052211 pin kdswh11: kdst_fetch dba 0x10a620e:1 time 1049052264 pin kdswh11: kdst_fetch dba 0x10a620f:1 time 1049052299 pin kdswh11: kdst_fetch dba 0x10a6211:1 time 1049052332 pin kdswh11: kdst_fetch dba 0x10a6212:1 time 1049052364 pin kdswh11: kdst_fetch dba 0x10a6213:1 time 1049052398 pin kdswh11: kdst_fetch dba 0x10a6214:1 time 1049052430 pin kdswh11: kdst_fetch dba 0x10a6215:1 time 1049052462 pin kdswh11: kdst_fetch dba 0x10a6216:1 time 1049052494 pin kdswh11: kdst_fetch dba 0x10a6217:1 time 1049052525 FETCH #47499559126280:c=0,e=371,p=0,cr=10,cu=0,mis=0,r=10,dep=1,og=1,plh=2568761675,tim=1343836186428807 ??pin 10????, ???fetch ?? WAIT #47499559136872: nam='PL/SQL lock timer' ela= 10002864 duration=0 p2=0 p3=0 obj#=-1 tim=1343836196431754 pin kdswh11: kdst_fetch dba 0x10a6218:1 time 1059055662 pin kdswh11: kdst_fetch dba 0x10a6219:1 time 1059055714 pin kdswh11: kdst_fetch dba 0x10a621a:1 time 1059055748 pin kdswh11: kdst_fetch dba 0x10a621b:1 time 1059055781 pin kdswh11: kdst_fetch dba 0x10a621c:1 time 1059055815 pin kdswh11: kdst_fetch dba 0x10a621d:1 time 1059055848 pin kdswh11: kdst_fetch dba 0x10a621e:1 time 1059055883 pin kdswh11: kdst_fetch dba 0x10a621f:1 time 1059055915 pin kdswh11: kdst_fetch dba 0x10a6221:1 time 1059055953 pin kdswh11: kdst_fetch dba 0x10a6222:1 time 1059055992 FETCH #47499559126280:c=0,e=385,p=0,cr=10,cu=0,mis=0,r=10,dep=1,og=1,plh=2568761675,tim=1343836196432274 ???? ??????? DBA????? ............................ ???? WAIT #47499559136872: nam='PL/SQL lock timer' ela= 10002933 duration=0 p2=0 p3=0 obj#=-1 tim=1343836366495589 pin kdswh11: kdst_fetch dba 0x10a62f6:1 time 1229119497 pin kdswh11: kdst_fetch dba 0x10a62f7:1 time 1229119545 pin kdswh11: kdst_fetch dba 0x10a62f8:1 time 1229119576 pin kdswh11: kdst_fetch dba 0x10a62f9:1 time 1229119610 pin kdswh11: kdst_fetch dba 0x10a62fa:1 time 1229119644 pin kdswh11: kdst_fetch dba 0x10a62fb:1 time 1229119671 pin kdswh11: kdst_fetch dba 0x10a62fc:1 time 1229119703 pin kdswh11: kdst_fetch dba 0x10a62fd:1 time 1229119730 pin kdswh11: kdst_fetch dba 0x10a62fe:1 time 1229119760 pin kdswh11: kdst_fetch dba 0x10a62ff:1 time 1229119787 FETCH #47499559126280:c=0,e=340,p=0,cr=10,cu=0,mis=0,r=10,dep=1,og=1,plh=2568761675,tim=1343836366496067 ??????DBA? 0x10a6203 , ??DBA ? 0x10a62ff ???????DBA??MACLEAN????????,???DBA???Maclean????? getbfno?????dba??????????? CREATE OR REPLACE FUNCTION getbfno (p_dba IN VARCHAR2) RETURN VARCHAR2 IS l_str VARCHAR2 (255) DEFAULT NULL; l_fno VARCHAR2 (15); l_bno VARCHAR2 (15); BEGIN l_fno := DBMS_UTILITY.data_block_address_file (TO_NUMBER (LTRIM (p_dba, '0x'), 'xxxxxxxx' ) ); l_bno := DBMS_UTILITY.data_block_address_block (TO_NUMBER (LTRIM (p_dba, '0x'), 'xxxxxxxx' ) ); l_str := 'datafile# is:' || l_fno || CHR (10) || 'datablock is:' || l_bno || CHR (10) || 'dump command:alter system dump datafile ' || l_fno || ' block ' || l_bno || ';'; RETURN l_str; END; / Function created. SQL> select getbfno('0x10a6203') from dual; GETBFNO('0X10A6203') -------------------------------------------------------------------------------- datafile# is:4 datablock is:680451 dump command:alter system dump datafile 4 block 680451; SQL> select getbfno('0x10a62ff') from dual; GETBFNO('0X10A62FF') -------------------------------------------------------------------------------- datafile# is:4 datablock is:680703 dump command:alter system dump datafile 4 block 680703; SQL> select dbms_rowid.rowid_block_number(min(rowid)),dbms_rowid.rowid_relative_fno(min(rowid)) from maclean; DBMS_ROWID.ROWID_BLOCK_NUMBER(MIN(ROWID)) ----------------------------------------- DBMS_ROWID.ROWID_RELATIVE_FNO(MIN(ROWID)) ----------------------------------------- 680451 4 SQL> select dbms_rowid.rowid_block_number(max(rowid)),dbms_rowid.rowid_relative_fno(max(rowid)) from maclean; DBMS_ROWID.ROWID_BLOCK_NUMBER(MAX(ROWID)) ----------------------------------------- DBMS_ROWID.ROWID_RELATIVE_FNO(MAX(ROWID)) ----------------------------------------- 680703 4 ???????3???: 1.?OPEN CURSOR ?????, PL/SQL????SQL????PARSE SQL????????, ??????OPEN CURSOR????SNAPSHOT SCN ??SCN, ??Oracle?????FETCH?????,???????????????? 2.????FETCH ?????????????? 3. ???open cursor+ fetch bulk collect???”?????????”

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• java.sql.SQLException: Parameter number X is not an OUT parameter

  - by Frederik

  Hi guys, I'm struggling with getting the result OUT variable from a MySQL stored procedure. I get the following error: java.sql.SQLException: Parameter number 3 is not an OUT parameter The stored procedure looks like this: CREATE DEFINER=`cv_admin`@`localhost` PROCEDURE `CheckGameEligibility`( IN gID INT(10), IN uID INT(10), OUT result TINYINT(1) ) BEGIN # Do lots of stuff, then eventually: SET result = 1; END My java function takes an array of strings* and creates the CallableStatement object dynamically: public static int callAndReturnResult( String sql , String[] values ) { int out = 0 ; try { // construct the SQL. Creates: CheckGameEligibility(?, ?, ?) sql += "(" ; for( int i = 0 ; i < values.length ; i++ ) { sql += "?, " ; } sql += "?)" ; System.out.println( "callAndReturnResult("+sql+"): constructed SQL: " + sql ); // Then the statement CallableStatement cstmt = DB.prepareCall( sql ); for( int i = 0 ; i < values.length ; i++ ) { System.out.println( " " + (i+1) + ": " + values[ i ] ) ; cstmt.setString(i+1, values[ i ] ); } System.out.println( " " + (values.length+1) + ": ? (OUT)" ) ; cstmt.registerOutParameter( values.length + 1 , Types.TINYINT ); cstmt.execute(); out = cstmt.getInt( values.length ); cstmt.close(); } catch( Exception e ) { System.out.println( "*** db trouble: callAndReturnResult(" + sql + " failed: " + e ); e.printStackTrace() ; } return out ; } *) I suppose I should be using an int array instead of a string array, but it doesn't seem to be what the error message was about. Anyway, here's the output it generates: callAndReturnResult(CheckGameEligibility(?, ?, ?)): constructed SQL: CheckGameEligibility(?, ?, ?) 1: 57 2: 29 3: ? (OUT) *** db trouble: callAndReturnResult(CheckGameEligibility(?, ?, ?) failed: java.sql.SQLException: Parameter number 3 is not an OUT parameter at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1075) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:984) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:929) at com.mysql.jdbc.CallableStatement.checkIsOutputParam(CallableStatement.java:692) at com.mysql.jdbc.CallableStatement.registerOutParameter(CallableStatement.java:1847) at org.apache.commons.dbcp.DelegatingCallableStatement.registerOutParameter(DelegatingCallabl>eStatement.java:92) at Tools.callAndReturnResult(Tools.java:156) Any ideas what might be the problem? :) Thanks in advance!

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• .NET converting simple arrays to List Generics

  - by Manish Sinha

  This question might seem trivial and also stupid at the first glance, but it is much more than this. I have an array of any type T (T[]) and I want to convert it into a List generic (List<T>). Is there any other way apart from creating a Generic list, traversing the whole array and adding the element in the List? Present Situation: string[] strList = {'foo','bar','meh'}; List<string> listOfStr = new List<string>(); foreach(string s in strList) { listOfStr.Add(s); } My ideal situation: string[] strList = {'foo','bar','meh'}; List<string> listOfStr = strList.ToList<string>(); Or: string[] strList = {'foo','bar','meh'}; List<string> listOfStr = new List<string>(strList); I am suggesting the last 2 method names as I think compiler or CLR can perform some optimizations on the whole operations if It want inbuilt. P.S.: I am not talking about the Array or ArrayList Type

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• ServerIdentity memory leak with IHttpAsyncHandler

  - by Anton

  I have a .NET web application that consists of a single HTTP handler class that implements IHttpAsyncHandler. All requests to this handler are handled asynchronously, though some requests are short-lived and some are long-lived (nothing over a few seconds). The problem is that memory consumption grows over time as requests are handled. All profiling results point to an unbounded growth of String objects held by instances of System.Runtime.Remoting.ServerIdentity. Every String value is different, but they all look similar to: /dd41c00e_1566_4702_b660_c81cdea18a43/vigefresi5pfv8n0ekddg57z_1154.rem There is nothing in my application that uses ServerIdentity directly, and unless I am mistaken, the ServerIdentity instances are proportional to the number of incoming requests. If this is an internal .NET structure, it looks like the CLR is not cleaning up after itself. What could be causing the leak? UPDATE A little less than half of the String objects are being held by System.Runtime.Remoting. The remaining String objects are being held by System.Runtime.Serialization and look similar to: +1sgess5rjcrgbmp3kqr6bmv_3474.rem Also, the problem only seems to occur when lots of simultaneous HTTP web requests arrive.

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• Hooking thread exit

  - by mackenir

  Is there a way for me to hook the exit of managed threads (i.e. run some code on a thread, just before it exits?) I've developed a mechanism for hooking thread exit that works for some threads. Step 1: develop a 'hook' STA COM class that takes a callback function and calls it in its destructor. Step 2: create a ThreadStatic instance of this object on the thread I want to hook, and pass the object a managed delegate converted to an unmanaged function pointer. The delegate then gets called on thread exit (since the CLR calls IUnknown::Release on all STA COM RCWs as part of thread exit). This mechanism works on, for example, worker threads that I create in code using the Thread class. However, it doesn't seem to work for the application's main thread (be it a console or windows app). The 'hook' COM object seems to be deleted too late in the shutdown process and the attempt to call the delegate fails. (The reason I want to implement this facility is so I can run some native COM code on the exiting thread that works with STA COM objects that were created on the thread, before it's 'too late' (i.e. before the thread has exited, and it's no longer possible to work with STA COM objects on that thread.))

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• .Net Finalizer Order / Semantics in Esent and Ravendb

  - by mattcodes

  Help me understand. I've read that "The time and order of execution of finalizers cannot be predicted or pre-determined" Correct? However looking at RavenDB source code TransactionStorage.cs I see this ~TransactionalStorage() { try { Trace.WriteLine( "Disposing esent resources from finalizer! You should call TransactionalStorage.Dispose() instead!"); Api.JetTerm2(instance, TermGrbit.Abrupt); } catch (Exception exception) { try { Trace.WriteLine("Failed to dispose esent instance from finalizer because: " + exception); } catch { } } } The API class (which belongs to Managed Esent) which presumable takes handles on native resources presumably using a SafeHandle? So if I understand correctly the native handles SafeHandle can be finalized before TransactionStorage which could have undesired effects, perhaps why Ayende has added an catch all clause around this? Actually diving into Esent code, it does not use SafeHandles. According to CLR via C# this is dangerous? internal static class SomeType { [DllImport("Kernel32", CharSet=CharSet.Unicode, EntryPoint="CreateEvent")] // This prototype is not robust private static extern IntPtr CreateEventBad( IntPtr pSecurityAttributes, Boolean manualReset, Boolean initialState, String name); // This prototype is robust [DllImport("Kernel32", CharSet=CharSet.Unicode, EntryPoint="CreateEvent")] private static extern SafeWaitHandle CreateEventGood( IntPtr pSecurityAttributes, Boolean manualReset, Boolean initialState, String name) public static void SomeMethod() { IntPtr handle = CreateEventBad(IntPtr.Zero, false, false, null); SafeWaitHandle swh = CreateEventGood(IntPtr.Zero, false, false, null); } } Managed Esent (NativeMEthods.cs) looks like this (using Ints vs IntPtrs?): [DllImport(EsentDll, CharSet = EsentCharSet, ExactSpelling = true)] public static extern int JetCreateDatabase(IntPtr sesid, string szFilename, string szConnect, out uint dbid, uint grbit); Is Managed Esent handling finalization/dispoal the correct way, and second is RavenDB handling finalizer the corret way or compensating for Managed Esent?

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• Reflecting over classes in .NET produces methods only differing by a modifier

  - by mrjoltcola

  I'm a bit boggled by something, I hope the CLR gearheads can help. Apparently my gears aren't big enough. I have a reflector utility that generates assembly stubs for Cola for .NET, and I find classes have methods that only differ by a modifier, such as virtual. Example below, from Oracle.DataAccess.dll, method GetType(): class OracleTypeException : System.SystemException { virtual string ToString (); virtual System.Exception GetBaseException (); virtual void set_Source (string value); virtual void GetObjectData (System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context); virtual System.Type GetType (); // here virtual bool Equals (object obj); virtual int32 GetHashCode (); System.Type GetType (); // and here } What is this? I have not been able to reproduce this with C# and it causes trouble for Cola as it thinks GetType() is a redefinition, since the signature is identical. My method reflector starts like this: static void DisplayMethod(MethodInfo m) { if ( // Filter out things Cola cannot yet import, like generics, pointers, etc. m.IsGenericMethodDefinition || m.ContainsGenericParameters || m.ReturnType.IsGenericType || !m.ReturnType.IsPublic || m.ReturnType.IsArray || m.ReturnType.IsPointer || m.ReturnType.IsByRef || m.ReturnType.IsPointer || m.ReturnType.IsMarshalByRef || m.ReturnType.IsImport ) return; // generate stub signature // [snipped] }

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• What are major differences between C# and Java?

  - by enba

  I just want to clarify one thing. This is not a question on which one is better, that part I leave to someone else to discuss. I don't care about it. I've been asked this question on my job interview and I thought it might be useful to learn a bit more. These are the ones I could come up with: Java is "platform independent". Well nowadays you could say there is the Mono project so C# could be considered too but I believe it is a bit exaggerating. Why? Well, when a new release of Java is done it is simultaneously available on all platforms it supports, on the other hand how many features of C# 3.0 are still missing in the Mono implementation? Or is it really CLR vs. JRE that we should compare here? Java doesn't support events and delegates. As far as I know. In Java all methods are virtual Development tools: I believe there isn't such a tool yet as Visual Studio. Especially if you've worked with team editions you'll know what I mean. Please add others you think are relevant. Update: Just popped up my mind, Java doesn't have something like custom attributes on classes, methods etc. Or does it?

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• C# Step by Step Execution

  - by Sheldon

  Hi. I'm building an app that uses and scanner API and a image to other format converter. I have a method (actually a click event) that do this: private void ButtonScan&Parse_Click(object sender, EventArgs e) { short scan_result = scanner_api.Scan(); if (scan_result == 1) parse_api.Parse(); // This will check for a saved image the scanner_api stores on disk, and then convert it. } The problem is that the if condition (scan_result == 1) is evaluated inmediatly, so it just don't work. How can I force the CLR to wait until the API return the convenient result. NOTE Just by doing something like: private void ButtonScan&Parse_Click(object sender, EventArgs e) { short scan_result = scanner_api.Scan(); MessageBox.Show("Result = " + scan_result); if (scan_result == 1) parse_api.Parse(); // This will check for a saved image the scanner_api stores on disk, and then convert it. } It works and display the results. Is there a way to do this, how? Thank you very much!

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• Criteria for triggering garbage collection in .Net

  - by Kennet Belenky

  I've come across some curious behavior with regard to garbage collection in .Net. The following program will throw an OutOfMemoryException very quickly (after less than a second on a 32-bit, 2GB machine). The Foo finalizer is never called. class Foo { static Dictionary<Guid, WeakReference> allFoos = new Dictionary<Guid, WeakReference>(); Guid guid = Guid.NewGuid(); byte[] buffer = new byte[1000000]; static Random rand = new Random(); public Foo() { // Uncomment the following line and the program will run forever. // rand.NextBytes(buffer); allFoos[guid] = new WeakReference(this); } ~Foo() { allFoos.Remove(guid); } static public void Main(string args[]) { for (; ; ) { new Foo(); } } } If the rand.nextBytes line is uncommented, it will run ad infinitum, and the Foo finalizer is regularly invoked. Why is that? My best guess is that in the former case, either the CLR or the Windows VMM is lazy about allocating physical memory. The buffer never gets written to, so the physical memory is never used. When the address space runs out, the system crashes. In the latter case, the system runs out of physical memory before it runs out of address space, the GC is triggered and the objects are collected. However, here's the part I don't get. Assuming my theory is correct, why doesn't the GC trigger when the address space runs low? If my theory is incorrect, then what's the real explanation?

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• C# language questions

  - by Water Cooler v2

  1) What is int? Is it any different from the struct System.Int32? I understand that the former is a C# alias (typedef or #define equivalant) for the CLR type System.Int32. Is this understanding correct? 2) When we say: IComparable x = 10; Is that like saying: IComparable x = new System.Int32(); But we can't new a struct, right? or in C like syntax: struct System.In32 *x; x=>someThing = 10; 3) What is String with a capitalized S? I see in Reflector that it is the sealed String class, which, of course, is a reference type, unlike the System.Int32 above, which is a value type. What is string, with an uncapitalized s, though? Is that also the C# alias for this class? Why can I not see the alias definitions in Reflector? 4) Try to follow me down this subtle train of thought, if you please. We know that a storage location of a particular type can only access properties and members on its interface. That means: Person p = new Customer(); p.Name = "Water Cooler v2"; // legal because as Name is defined on Person. but // illegal without an explicit cast even though the backing // store is a Customer, the storage location is of type // Person, which doesn't support the member/method being // accessed/called. p.GetTotalValueOfOrdersMade(); Now, with that inference, consider this scenario: int i = 10; // obvious System.object defines no member to // store an integer value or any other value in. // So, my question really is, when the integer is // boxed, what is the *type* it is actually boxed to. // In other words, what is the type that forms the // backing store on the heap, for this operation? object x = i;

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• How do you protect yourself from runaway memory consumption bringing down the PC?

  - by romkyns

  Every now and again I find myself doing something moderately dumb that results in my program allocating all the memory it can get and then some. This kind of thing used to cause the program to die fairly quickly with an "out of memory" error, but these days Windows will go out of its way to give this non-existent memory to the application, and in fact is apparently prepared to commit suicide doing so. Not literally of course, but it will starve itself of usable physical RAM so badly that even running the task manager will require half an hour of swapping (after all the runaway application is still allocating more and more memory all the time). This doesn't happen too often, but when it does it's disastrous. I usually have to reset my machine, causing data loss from time to time and generally a lot of inconvenience. Do you have any practical advice on making the consequences of such a mistake less dire? Perhaps some registry tweak to limit the max amount of virtual memory an app is allowed to allocate? Or some CLR flag that will limit this only for the current application? (It's usually in .NET that I do this to myself.) ("Don't run out of RAM" and "Buy more RAM" are no use - the former I have no control over, and the latter I've already done.)

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• Management and Monitoring Tools for Windows Azure

  - by BuckWoody

  With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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• Management and Monitoring Tools for Windows Azure

  - by BuckWoody

  With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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• SQL Server Table Polling by Multiple Subscribers

  - by Daniel Hester

  Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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• 24 Hours of PASS – first reflections

  - by Rob Farley

  A few days after the end of 24HOP, I find myself reflecting on it. I’m still waiting on most of the information. I want to be able to discover things like where the countries represented on each of the sessions, and things like that. So far, I have the feedback scores and the numbers of attendees. The data was provided in a PDF, so while I wait for it to appear in a more flexible format, I’ve pushed the 24 attendee numbers into Excel. This chart shows the numbers by time. Remember that we started at midnight GMT, which was 10:30am in my part of the world and 8pm in New York. It’s probably no surprise that numbers drooped a bit at the start, stayed comparatively low, and then grew as the larger populations of the English-speaking world woke up. I remember last time 24HOP ran for 24 hours straight, there were quite a few sessions with less than 100 attendees. None this time though. We got close, but even when it was 4am in New York, 8am in London and 7pm in Sydney (which would have to be the worst slot for attracting people), we still had over 100 people tuning in. As expected numbers grew as the UK woke up, and even more so as the US did, with numbers peaking at 755 for the “3pm in New York” session on SQL Server Data Tools. Kendra Little almost reached those numbers too, and certainly contributed the biggest ‘spike’ on the chart with her session five hours earlier. Of all the sessions, Kendra had the highest proportion of ‘Excellent’s for the “Overall Evaluation of the session” question, and those of you who saw her probably won’t be surprised by that. Kendra had one of the best ranked sessions from the 24HOP event this time last year (narrowly missing out on being top 3), and she has produced a lot of good video content since then. The reports indicate that there were nearly 8.5 thousand attendees across the 24 sessions, averaging over 350 at each one. I’m looking forward to seeing how many different people that was, although I do know that Wil Sisney managed to attend every single one (if you did too, please let me know). Wil even moderated one of the sessions, which made his feat even greater. Thanks Wil. I also want to send massive thanks to Dave Dustin. Dave probably would have attended all of the sessions, if it weren’t for a power outage that forced him to take a break. He was also a moderator, and it was during this session that he earned special praise. Part way into the session he was moderating, the speaker lost connectivity and couldn’t get back for about fifteen minutes. That’s an incredibly long time when you’re in a live presentation. There were over 200 people tuned in at the time, and I’m sure Dave was as stressed as I was to have a speaker disappear. I started chasing down a phone number for the speaker, while Dave spoke to the audience. And he did brilliantly. He started answering questions, and kept doing that until the speaker came back. Bear in mind that Dave hadn’t expected to give a presentation on that topic (or any other), and was simply drawing on his SQL expertise to get him through. Also consider that this was between midnight at 1am in Dave’s part of the world (Auckland, NZ). I would’ve been expecting just to welcome people, monitor questions, probably read some out, and in general, help make things run smoothly. He went far beyond the call of duty, and if I had a medal to give him, he’d definitely be getting one. On the whole, I think this 24HOP was a success. We tried a different platform, and I think for the most part it was a popular move. We didn’t ask the question “Was this better than LiveMeeting?”, but we did get a number of people telling us that they thought the platform was very good. Some people have told me I get a chance to put my feet up now that this is over. As I’m also co-ordinating a tour of SQLSaturday events across the Australia/New Zealand region, I don’t quite get to take that much of a break (plus, there’s the little thing of squeezing in seven SQL 2012 exams over the next 2.5 weeks). But I am pleased to be reflecting on this event rather than anticipating it. There were a number of factors that could have gone badly, but on the whole I’m pleased about how it went. A massive thanks to everyone involved. If you’re reading this and thinking you wish you could’ve tuned in more, don’t worry – they were all recorded and you’ll be able to watch them on demand very soon. But as well as that, PASS has a stream of content produced by the Virtual Chapters, so you can keep learning from the comfort of your desk all year round. More info on them at sqlpass.org, of course.

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• [SQLServer JDBC Driver][SQLServer]Could not find stored procedure 'master..xp_jdbc_open2'.

  - by Vijaya Moderator -Oracle

  When connecting to MS SQL Server Database via Weblogic Datasource and using XA jdbc driver, the following error is thrown. <Jun 3, 2014 5:16:49 AM PDT> <Error> <Console> <BEA-240003> <Console encountered the following error java.sql.SQLException: [FMWGEN][SQLServer JDBC Driver][SQLServer]Could not find stored procedure 'master..xp_jdbc_open2'. at weblogic.jdbc.sqlserverbase.ddb_.b(Unknown Source)at weblogic.jdbc.sqlserverbase.ddb_.a(Unknown Source)at weblogic.jdbc.sqlserverbase.ddb9.b(Unknown Source)at weblogic.jdbc.sqlserverbase.ddb9.a(Unknown Source)at weblogic.jdbc.sqlserver.tds.ddr.v(Unknown Source)at weblogic.jdbc.sqlserver.tds.ddr.a(Unknown Source)at weblogic.jdbc.sqlserver.tds.ddq.a(Unknown Source)at weblogic.jdbc.sqlserver.tds.ddr.a(Unknown Source)at weblogic.jdbc.sqlserver.ddj.m(Unknown Source)at weblogic.jdbc.sqlserverbase.ddel.e(Unknown Source)at weblogic.jdbc.sqlserverbase.ddel.a(Unknown Source)  The cause behind the issue is that  the MS SQL Server was not installed with the Stored procedures to enable JTA/XA Solution To connect to SQL Server via XA Driver from WLS Datasource you need to install Stored Procedures for JTATo use JDBC distributed transactions through JTA, your system administrator should use the following procedure to install Microsoft SQL Server JDBC XA procedures. This procedure must be repeated for each MS SQL Server installation that will be involved in a distributed transaction.To install stored procedures for JTA:1. Copy the appropriate sqljdbc.dll and instjdbc.sql files from the WL_HOME\server\lib directory to the SQL_Server_Root/bin directory of the MS SQL Server database server, where WL_HOME is the directory in which WebLogic server is installed, typically c:\Oracle\Middleware\wlserver_10.x.  Note:  If you are installing stored procedures on a database server with multiple Microsoft SQL Server instances, each running SQL Server instance must be able to locate the sqljdbc.dll file.Therefore the sqljdbc.dll file needs to be anywhere on the global PATH or on the application-specific path. For the application-specific path, place the sqljdbc.dll file into the :\Program Files\Microsoft SQL Server\MSSQL$\Binn directory for each instance. 2. From the database server, use the ISQL utility to run the instjdbc.sql script. As a precaution, have your system administrator back up the master database before running instjdbc.sql. At a command prompt, use the following syntax to run instjdbc.sql:  ISQL -Usa -Psa_password -Sserver_name -ilocation\instjdbc.sql  where:  sa_password is the password of the system administrator.  server_name is the name of the server on which SQL Server resides.  location is the full path to instjdbc.sql. (You copied this script to the SQL_Server_Root/bin directory in step 1.)  The instjdbc.sql script generates many messages. In general, these messages can be ignored; however, the system administrator should scan the output for any messages that may indicate an execution error. The last message should indicate that instjdbc.sql ran successfully. The script fails when there is insufficient space available in the master database to store the JDBC XA procedures or to log changes to existing procedures.

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• Enable Automatic Code First Migrations On SQL Database in Azure Web Sites

  - by Steve Michelotti

  Now that Azure supports .NET Framework 4.5, you can use all the latest and greatest available features. A common scenario is to be able to use Entity Framework Code First Migrations with a SQL Database in Azure. Prior to Code First Migrations, Entity Framework provided database initializers. While convenient for demos and prototypes, database initializers weren’t useful for much beyond that because, if you delete and re-create your entire database when the schema changes, you lose all of your operational data. This is the void that Migrations are meant to fill. For example, if you add a column to your model, Migrations will alter the database to add the column rather than blowing away the entire database and re-creating it from scratch. Azure is becoming increasingly easier to use – especially with features like Azure Web Sites. Being able to use Entity Framework Migrations in Azure makes deployment easier than ever. In this blog post, I’ll walk through enabling Automatic Code First Migrations on Azure. I’ll use the Simple Membership provider for my example. First, we’ll create a new Azure Web site called “migrationstest” including creating a new SQL Database along with it:   Next we’ll go to the web site and download the publish profile:   In the meantime, we’ve created a new MVC 4 website in Visual Studio 2012 using the “Internet Application” template. This template is automatically configured to use the Simple Membership provider. We’ll do our initial Publish to Azure by right-clicking our project and selecting “Publish…”. From the “Publish Web” dialog, we’ll import the publish profile that we downloaded in the previous step:   Once the site is published, we’ll just click the “Register” link from the default site. Since the AccountController is decorated with the [InitializeSimpleMembership] attribute, the initializer will be called and the initial database is created.   We can verify this by connecting to our SQL Database on Azure with SQL Management Studio (after making sure that our local IP address is added to the list of Allowed IP Addresses in Azure): One interesting note is that these tables got created with the default Entity Framework initializer – which is to create the database if it doesn’t already exist. However, our database did already exist! This is because there is a new feature of Entity Framework 5 where Code First will add tables to an existing database as long as the target database doesn’t contain any of the tables from the model. At this point, it’s time to enable Migrations. We’ll open the Package Manger Console and execute the command: PM> Enable-Migrations -EnableAutomaticMigrations This will enable automatic migrations for our project. Because we used the "-EnableAutomaticMigrations” switch, it will create our Configuration class with a constructor that sets the AutomaticMigrationsEnabled property set to true: 1: public Configuration() 2: { 3: AutomaticMigrationsEnabled = true; 4: } We’ll now add our initial migration: PM> Add-Migration Initial This will create a migration class call “Initial” that contains the entire model. But we need to remove all of this code because our database already exists so we are just left with empty Up() and Down() methods. 1: public partial class Initial : DbMigration 2: { 3: public override void Up() 4: { 5: } 6: 7: public override void Down() 8: { 9: } 10: } If we don’t remove this code, we’ll get an exception the first time we attempt to run migrations that tells us: “There is already an object named 'UserProfile' in the database”. This blog post by Julie Lerman fully describes this scenario (i.e., enabling migrations on an existing database). Our next step is to add the Entity Framework initializer that will automatically use Migrations to update the database to the latest version. We will add these 2 lines of code to the Application_Start of the Global.asax: 1: Database.SetInitializer(new MigrateDatabaseToLatestVersion<UsersContext, Configuration>()); 2: new UsersContext().Database.Initialize(false); Note the Initialize() call will force the initializer to run if it has not been run before. At this point, we can publish again to make sure everything is still working as we are expecting. This time we’re going to specify in our publish profile that Code First Migrations should be executed:   Once we have re-published we can once again navigate to the Register page. At this point the database has not been changed but Migrations is now enabled on our SQL Database in Azure. We can now customize our model. Let’s add 2 new properties to the UserProfile class – Email and DateOfBirth: 1: [Table("UserProfile")] 2: public class UserProfile 3: { 4: [Key] 5: [DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)] 6: public int UserId { get; set; } 7: public string UserName { get; set; } 8: public string Email { get; set; } 9: public DateTime DateOfBirth { get; set; } 10: } At this point all we need to do is simply re-publish. We’ll once again navigate to the Registration page and, because we had Automatic Migrations enabled, the database has been altered (*not* recreated) to add our 2 new columns. We can verify this by once again looking at SQL Management Studio:   Automatic Migrations provide a quick and easy way to keep your database in sync with your model without the worry of having to re-create your entire database and lose data. With Azure Web Sites you can set up automatic deployment with Git or TFS and automate the entire process to make it dead simple.

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