SELECT hangs despite Snapshot Isolation

- I'm trying to learn isolation levels.
   SET TRANSACTION ISOLATION LEVEL Read Snapshot
I thought this would allow me to issue a SELECT on a dirty row (I thought it would show me the clean version of the row). But my test failed - the SELECT hangs/pends. Why?
- First I dirtied a row:
   if object_id('tblTestTrans') is not null drop table tblTestTrans
   create table tbltestTrans (
       id int
   insert into tbltestTrans (id) values (1)
   Begin Tran
       Update tbltestTrans set id = 2
Then I ran a SELECT in a new query window:
   ALTER DATABASE TestDb Set Allow_SnapShot_Isolation ON
   SET TRANSACTION ISOLATION LEVEL Snapshot
   select * from tblTestTrans -- hangs
The select hangs. Why?

Your test seems a little incomplete. You should set the connection which is starting transaction to snapshot before running an update. Then you can open another connection and set it to snapshot to see only the clean version of the table (with
only one record).

Similar Messages

Snapshot isolation in combination with service broker

Hi all,
I'm currently using the service broker in combination with snapshot isolation on the database.
The notification request is executed under read commited isolation. The code looks like this:
SqlDependency dependency = new SqlDependency(command, null, 0);
dependency.OnChange += eventHandler;
using (SqlConnection conn = new SqlConnection(connectionString))
using (SqlTransaction tran = conn.BeginTransaction(IsolationLevel.ReadCommitted))
command.Transaction = tran;
command.ExecuteNonQuery();
tran.Commit();
The request is successfully created and works fine at the first glance.
Now here is my problem:
I created a notification request that should monitor two objects. The query (executed under read committed) looks something like this:
SELECT Id, DataVersion FROM dbo.MyObjects WHERE Id = 1 OR Id = 2
Afterwards I delete both objects in separate nested transactions. Both of them are running under snapshot isolation. It looks something like this:
using (SqlConnection conn1 = new SqlConnection(connectionString))
conn1.Open();
using (SqlTransaction tran1 = connection1.BeginTransaction(IsolationLevel.Snapshot))
using (SqlConnection conn2 = new SqlConnection(connectionString))
conn2.Open();
using (SqlTransaction tran2 = conn2.BeginTransaction(IsolationLevel.Snapshot))
SqlCommand command2 = conn2.CreateCommand();
command2.Transaction = tran2;
command2.CommandText = "DELETE FROM MyObjects WHERE Id = 2";
command2.ExecuteNonQuery();
tran2.Commit();
SqlCommand command1 = conn1.CreateCommand();
command1.CommandText = "DELETE FROM MyObjects WHERE Id = 1";
command1.Transaction = tran1;
command1.ExecuteNonQuery();
tran1.Commit(); //-> Conflict exception
A conflict exception is raised during the commit of last transaction. The conflict seems to occur in the table "sys.query_notifcations_xxxxxxxxx". This is the exact message:
An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll
Additional information: Snapshot isolation transaction aborted due to update conflict. You cannot use snapshot isolation to access table 'sys.query_notification_45295271' directly or indirectly in database 'MyDatabase' to update, delete,
or insert the row that has been modified or deleted by another transaction. Retry the transaction or change the isolation level for the update/delete statement.
Is there any restriction for the service broker that prohibits the usage of snapshot isolation.
Thanks in advance.

No, the error has nothing to do with Service Broker. Or for that matter, query notifications, which is the feature you are actually using. (Query notifications uses Service Broker, but Service Broker != Query notification.)
You would get the same error if you had a trigger in MyObjects that tried to update the same row for both deletions. A snapshot transaction gives you a consistent view of the database in a certain point in time. Consider this situation:
Snapshot transaction A that started at time T update a row R at time T2. Snapshot transaction B starts at time T1 updates the same row at time T3. Had they been regular non-snapshot transaction, transaction B would have been blocked already when it tried
to read R, but snapshot transactions do not get blocked. But if B would be permitted to update R, the update from transaction A would be lost. Assume that the update is an incremental one, for instance updating cash balance for an account. You can see that
this is not permittable.
In your case, the row R happens to be a row in an internal table for query notifications, but it is the application design which is the problem. There is no obvious reason to use snapshot isolation in your example since you are only deleting. And there is
even less reason to have two transactions and connections for the task.
Erland Sommarskog, SQL Server MVP, [email protected]

Pls tel me what is the diffrence between snapshot isolation level of mssql and oracels isolation level

Hi,
In mssql i am using following things.
I have two database D1 and D2, i am using snapshot isolation (ALTER DATABASE MyDatabase
SET ALLOW_SNAPSHOT_ISOLATION ON) in both database.
Following is the situation.
1) There is one SP sp1 ( it can be in any database d1 or d2), it updates d2 from d1.
2) d2 is used for reading by web, execept above SP sp1
3) d1 gets updation from web in readcommite isolation.
4) both database will be on same instence of mssql.
Q1) wanted to know how to implement the same thing in oracle 11x express edition.
Q2) is there any diffrence between snapshot isolation level of mssql and oracel.
any link would be help full.
yours sincerely

>Q1) should i set the option to OFF after the process(ts) is complete
No keep it on.
>Q2) ALLOW_SNAPSHOT_ISOLATION ON , will affect other isolation level's transactions
No it will not affect any other transaction isolation level.
>Q3) is my choice of isolation level for process(ts) is correct or there can be any other solution.
Seems fine, although there are probably many other solutions.
David
David http://blogs.msdn.com/b/dbrowne/

Snapshot isolation transaction aborted due to update conflict

Hi Forum,
Can anyone help me to give the solution for this below problem.
We are developing MVC3 application with SQL Server 2008, we are facing as
Snapshot isolation transaction aborted due to update conflict
Snapshot isolation transaction aborted due to update conflict. You cannot use snapshot isolation to access table 'dbo.Tb_M_Print' directly or indirectly in database 'DB_Production' to update, delete, or insert the row that has been modified or deleted
by another transaction. Retry the transaction or change the isolation level for the update/delete statement .
Please tell me the solution how to proceed for the above problem
Rama

change the isolation level for the update/delete statement .
The error message already mentions the solution.
See also MSDN
Lesson 1: Understanding the Available Transaction Isolation Levels => Update Conflicts
Olaf Helper
[ Blog] [ Xing] [ MVP]

Segmentation fault when using snapshot isolation with Berkeley DB 6.1.19 and 5.1.29

Hello,
I have been experimenting with snapshot isolation with Berkeley DB, but I find that it frequently triggers a segmentation fault when write transactions are in progress. The following test program reliably demonstrates the problem in Linux using either 5.1.29 or 6.1.19.
https://anl.app.box.com/s/3qq2yiij2676cg3vkgik
Compilation instructions are at the top of the file. The test program creates a temporary directory in /tmp, opens a new environment with the DB_MULTIVERSION flag, and spawns 8 threads. Each thread performs 100 transactional put operations using DB_TXN_SNAPSHOT. The stack trace when the program crashes generally looks like this:
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff7483700 (LWP 11871)]
0x00007ffff795e190 in __memp_fput ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
(gdb) where
#0 0x00007ffff795e190 in __memp_fput ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#1 0x00007ffff7883c30 in __bam_get_root ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#2 0x00007ffff7883dca in __bam_search ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#3 0x00007ffff7870246 in ?? () from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#4 0x00007ffff787468f in ?? () from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#5 0x00007ffff79099f4 in __dbc_iput ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#6 0x00007ffff7906c10 in __db_put ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#7 0x00007ffff79191eb in __db_put_pp ()
   from /usr/lib/x86_64-linux-gnu/libdb-5.1.so
#8 0x0000000000400f14 in thread_fn (foo=0x0)
    at ../tests/transactional-osd/bdb-snapshot-write.c:154
#9 0x00007ffff7bc4182 in start_thread (arg=0x7ffff7483700)
    at pthread_create.c:312
#10 0x00007ffff757f38d in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111
I understand that this test program, with 8 concurrent (and deliberately conflicting) writers, is not an ideal use case for snapshot isolation, but this can be triggered in other scenarios as well.
You can disable snapshot isolation by toggling the value of the USE_SNAP #define near the top of the source, and the test program then runs fine without it.
Can someone help me to identify the problem?
many thanks,
-Phil

Hi Phil,
   We have taken a look at this in more detail and there was a bug in the code.   We have fixed the bug.     We will roll it into our next 6.1 release that we do.   If you would like an early patch that will go on top of 6.1.19, please email me at [email protected], reference this forum post and I can get a patch sent out to you.   It will be a .diff file that apply on the source code and then rebuild the library. Once again thanks for finding the issue, and providing a great test program which tremendously helped in getting this resolved.
thanks
mike

Snapshot isolation level usage

Dear All,
There are some transaction tables in which more than one user add and update records (only).
what ever they add and update in transaction tables, based on that entry they add a record in Table A1
, Table A1 has two cols one keeps the table name of transaction table and other col keeps the pk(primarykey) of transaction tables.
So Table A1 always gets only inserts,
Table A1 gets entry only for transaction tables , and only when transaction table gets entry .
At the same time there is a process (ts) which reads Table A1 on time basis, picks up all records
form Table A1 and reads data from transaction tables on the basis of PK stored in it . there it after inserts all the read records into a
new temp table.
and at the end of transaction it deletes records from Table A1.
after some time it again picks up new records from Table A1 and repeats the process.
For process (ts) . i want to use ALLOW_SNAPSHOT_ISOLATION
so that user can keep on entering records.
Q1) The ALLOW_SNAPSHOT_ISOLATION
database option must be set to ON
before one can start a transaction that uses the SNAPSHOT isolation level. I wanted to know should i set the option to OFF after the process(ts) is complete, and switch
it on again on the database when process(ts) starts again.
that is, keeping it on all the time will affect the database in any case?
Q2) ALLOW_SNAPSHOT_ISOLATION ON , will affect other isolation level's transactions or only to snapshot isolation levels transactions. that is, i have old
stored proc and front end applications like web or window on .net which are using default isolation levels.
Q3) is my choice of isolation level for process(ts) is correct or there can be any other solution.
Note: "the information is quite less but i wont be able to give full information."
yours sincerely

>Q1) should i set the option to OFF after the process(ts) is complete
No keep it on.
>Q2) ALLOW_SNAPSHOT_ISOLATION ON , will affect other isolation level's transactions
No it will not affect any other transaction isolation level.
>Q3) is my choice of isolation level for process(ts) is correct or there can be any other solution.
Seems fine, although there are probably many other solutions.
David
David http://blogs.msdn.com/b/dbrowne/

( if snapshot isolation level is enable in db.) Is the version chain is generated if any read commited transation is executed or it only gnerates version chain, if any snapshot transaction is in running status.

hi,
I have enable snapshot isolation level, in my database all queries execute in read commited isolation only one big transaction uses snapshot isolation.
q1)i wanted to know if snapshot silation transaction is not running but database is enable for snapshot ,then will the normal
queries using read commited will create versions or not.
yours sincerley.

Enabling snapshot isolation level on DB level does not change behavior of queries in any other isolation levels. In that option you are eliminating all blocking even between writers (assuming they do not update
the same rows) although it could lead to 3960 errors (data has been modified by other sessions).
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
MS SQL optimization: MS SQL Development and Optimization
MS SQL Consulting:
Large scale of database and data cleansing
Remote DBA Services:
Improves MS SQL Database Performance
SQL Server Integration Services:
Business Intelligence

Berkeley DB's Snapshot Isolation

After read the reference document, I think snapshot isolation means that a write operation will take a read lock in the data page under a transation. After that another transaction with read operation can read the page.But I code it like this:
step1:txn1 update the page but not commited
step2:txn2 read the page
step3:commit txn1
step4:commit txn2
The program is stop in step2 and wait forever.Then I change step1 for read, It can excete normally.That's seems like the snapshot isolation is still take a wirte lock int the page.I feel confuss about how snapshot isolation works.
If someone can give me an example program , or tell me how it works , I will thank you quit a lot.

Hi,mike,thanks for you answer.I read the document again and again today.According to the suggestion,we usually use snapshot in a read-only transaction and another update transation to write. So I recode my program with a read-only transaction and a update transaction.But it is also blocked like before.I feel so confuse. I put my program here and wish you can help me with that. thanks for your time.
#include"db_cxx.h"
#include<iostream>
#include<cstring>
int main()
u_int32_t env_flags =     DB_CREATE |
                                     DB_INIT_LOCK |
                                     DB_INIT_LOG |
                                     DB_INIT_MPOOL |
                                     DB_INIT_TXN;
const char* home = "envHome";
u_int32_t db_flags = DB_CREATE | DB_AUTO_COMMIT;
const char* fileName = "envtest.db";
Db* dbp = NULL;
DbEnv myEnv(0);
try{
       myEnv.open(home,env_flags,0);
       myEnv.set_flags(DB_MULTIVERSION,1);
       dbp = new Db(&myEnv,0);
       dbp->open(
                           NULL,           //Txn pointer
                           fileName,      //File name
                           NULL,           //Logic db name
                           DB_BTREE, //Database type
                           db_flags,      //Open flags
                           0                //file mode
}catch(DbException &e){
       std::cerr<<"Error when opening database and Environment:"
                      <<fileName<<","<<home<<std::endl;
       std::cerr<<e.what()<<std::endl;
//put data normally
char *key1 = "luffy";
char *data1 = "op";
char *key2= "usopp";
char *data2 = "brave";
Dbt pkey1(key1,strlen(key1)+1);
Dbt pdata1(data1,strlen(data1)+1);
Dbt pkey2(key2,strlen(key2)+1);
Dbt pdata2(data2,strlen(data2)+1);
dbp->put(NULL,&pkey1,&pdata1,0);
dbp->put(NULL,&pkey2,&pdata2,0);
//using txn cursor to read and another cursor to modify before commit
try{
       DbTxn *txn1 = NULL;
       myEnv.txn_begin(NULL,&txn1,DB_SNAPSHOT);
       Dbc *cursorp = NULL;
       dbp->cursor(txn1,&cursorp,0);
       Dbt tempData1,tempKey2,tempData2;
       tempData2.set_flags(DB_DBT_MALLOC);
       cursorp->get(&pkey1,&tempData1,DB_SET);
       cursorp->get(&tempKey2,&tempData2,DB_NEXT);
       //cout just to see if it is right
       std::cout<<(char*)pkey1.get_data()<<" : "<<(char*)tempData1.get_data()<<std::endl
                          <<(char*)tempKey2.get_data()<<" : "<<(char*)tempData2.get_data()<<std::endl;
       //txn2 to modify
       DbTxn *txn2 = NULL;
       myEnv.txn_begin(NULL,&txn2,0);
       Dbc *temcur = NULL;
       dbp->cursor(txn2,&temcur,0);
       temcur->put(&pkey1,&pdata2,DB_KEYFIRST);          //the program will stop here and wait forever. if the snapshop isolation made a copy before , why still block here?
                                                                                     //without this line,there won't deadlock.that means page was put a write lock before
       //commit the txn
       txn1->commit(0);
       txn2->commit(0);
}catch(DbException &e){
      std::cerr<<"Error when use a txn"<<std::endl;
try{
       dbp->close(0); //dbp should close before environment
       myEnv.close(0);
}catch(DbException &e){
       std::cerr<<"Error when closing database and environment:"
                                <<fileName<<","<<home<<std::endl;
       std::cerr<<e.what()<<std::endl;
return 0;

Alter table modify lob shrink space hangs despite ddl_lock_timeout

Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
The following command hangs despite session parameter ddl_lock_timeout being set to 0:
alter table <table> modify lob (<column>) (shrink space);
Data type of <column> is CLOB. In another session a transaction on <table> is open, with a simple update on a different (non-LOB) column.
Looks like a bug to me, but have no access to metalink for confirmation/SR submission and would appreciate any comments/help on this issue.

From Oracle 11 documentation ( http://docs.oracle.com/cd/B28359_01/server.111/b28310/schema003.htm#CBBBIADA )
"Segment shrink is an online, in-place operation. DML operations and queries can be issued during the data movement phase of segment shrink."
Simon

Snapshot isolation

We have setup snapshot level isolation in our Berkeley DB XML database, and started getting the following errors during queries after a while:
PANIC: Cannot allocate memory
We set the max lockers at 10,000, max locks at 1,000,000 and max lock objects at 1,000,000 as well. We are also very careful to commit or abort every transaction initiated. All of our operations are done under the context of an explicit transaction. Could there be some memory leak? Should we be aware of some other caveats?
Thank you,
Alexander.

Hi Alexander,
I would suggest running the application under a memory leak checker/debugger, such as Purify or Valgrind. If you do get something suspicious please report it.
Though, when running with snapshot isolation you have to be prepared for the cost that MVCC (MultiVersion Concurrency Control) implies, that is, larger cache size requirements.
Pages are being duplicated when a writer takes a read lock on a page, therefore operating on a copy of that page. This avoids the situation where other writers would block due to a read lock held on the page, but it also means that the cache will fill up faster. You might need a larger cache in order to hold the entire working set in memory.
Note that the need of more cache is amplified when you have a large number of concurrent active long-running transactions, as it increases the volume of active page versions (copies of pages that cannot safely be freed). In such situation, it may worth trying to run updates at serializable isolation and only run queries at snapshot isolation. The queries will not block updates, or vice versa, and the updates will not force page versions to be kept for long periods.
You should try keeping the transactions running under snapshot isolation as short as possible.
Of course, the recommended approach to resolve this issue is to increase the cache size, if possible. You can estimate how large your cache should be by taking a checkpoint, followed by a call to the DB_ENV->log_archive() method. The amount of cache required is approximately double the size of the remaining log files (that is, the log files that cannot be archived).
Also, along with increasing the cache size you may need to increase the number of maximum active transactions that the application supports.
Please review the following places for further information:
[http://www.oracle.com/technology/documentation/berkeley-db/db/programmer_reference/transapp_read.html#id1609299]
[http://www.oracle.com/technology/documentation/berkeley-db/db/gsg_txn/Java/isolation.html#snapshot_isolation]
Regards,
Andrei

Turning On Snapshot Isolation Gotchas

Hello Experts,
We have been experiencing high number of Deadlocks while using MERGE statement and turning on Snapshot Isolation perfectly solves our problem and our throughput and concurrency didn't get affected at all.
We did load testing and monitored TempDB VersionStore size and it was nothing significant and we have 64 Gig Memory allocated in Prod Server. Our team did the reading and research primarily from these online sources.
My Question is "Is there any gotchas in turing on SnapShot Isolation you won't see right away?". I want learn from experiences before we venture into turning it on in our production Environment?. I saw some folks experienced 60 Gig Version Store
because there was 3 month old active transaction.
What kind of preventive and maintenance scripts would be useful to monitor the system and take corrective action?.
I have few scripts to monitor tempdb version store size, and peformon Transaction Counters. Is there any other better scripts/tools available?.
Kimberly Tripp Video on Isolation Levels :
http://download.microsoft.com/download/6/7/9/679B8E59-A014-4D88-9449-701493F2F9FD/HDI-ITPro-TechNet-mp4video-MCM_11_SnapshotIsolationLecture(4).m4v
Kendra Little on SnapShot Isolatioin :
http://www.brentozar.com/archive/2013/01/implementing-snapshot-or-read-committed-snapshot-isolation-in-sql-server-a-guide/
Microsoft Link: https://msdn.microsoft.com/en-us/library/ms188277(v=sql.105).aspx
https://msdn.microsoft.com/en-us/library/bb522682.aspx
SQL Team Link : http://www.sqlteam.com/article/transaction-isolation-and-the-new-snapshot-isolation-level
Idera Short article on TempDB : http://sqlmag.com/site-files/sqlmag.com/files/uploads/2014/01/IderaWP_Demystifyingtempdb.pdf
Jim Gray Example by Craig Freedman : http://blogs.msdn.com/b/craigfr/archive/2007/05/16/serializable-vs-snapshot-isolation-level.aspx
Thanks in advance.
~I90Runner
I90Runner

It is unclear what isolation level have you enabled RCSI or SI?
Downsides:
Excessive tempdb usage due to version store activity. Think about session that deletes 1M rows. All those rows must be copied to version store regardless of session transaction isolation level and/or if there are other sessions
that running in optimistic isolation levels at the moment when deletion started.
Extra fragmentation – SQL Server adds 14-byte version tag (version store pointer) to the rows in the data files when they are modified. This tag stayed until index is rebuild
Development challenges – again, error 3960 with snapshot isolation level. Another example in both isolation levels – trigger or code based referential integrity. You can always solve it by adding with (READCOMMITTED) hint
if needed.
While switching to RCSI could be good emergency technique to remove blocking between readers and writers (if you can live with overhead AND readers are using read committed), I would suggest to find root cause of the blocking.
Confirm that you have locking issues – check if there are shared lock waits in wait stats, that there is no lock escalations that block readers, check that queries are optimized, etc.
Best Regards,Uri Dimant SQL Server MVP,
http://sqlblog.com/blogs/uri_dimant/
MS SQL optimization: MS SQL Development and Optimization
MS SQL Consulting:
Large scale of database and data cleansing
Remote DBA Services:
Improves MS SQL Database Performance
SQL Server Integration Services:
Business Intelligence

Text Selection Hangs Since iOS 5.1.1 Update

I have an iPhone 4 32GB on the AT&T network.
Updated it to iOS 5.1.1 about two weeks ago.
Since the update multiple applications (Apple and 3rd Party) have been showing this behavior:
1) Click in a text entry or text area form field,
2) Begin typing text,
3) Touch anywhere in the field to bring up the monicle selection caret,
4) The monical selection caret is shown and I can move the monical/caret around the screen,
5) Un-touch the screen,
6) ERROR - The monicle and the selection caret don't respond to user touch input and the app/OS hang for anywhere from 5 to 15 seconds,
7) The standard "Select | Select All | ..." context pop-up window is shown, after that the app/system are responsive again.
Regarding the ERROR at step 6) above: Clicking Home does nothing, turning on/off with top-button does nothing, force shutdown responds only after the monicle/caret selector un-hangs.
Once this has happened in a given text field/text area, it doesn't happen again on a subsequent text selection touch event... UNLESS I sleep the device, wake the device on the same app/field and try to select again... then it hangs again.
To note, while it's hanging the loading-spinner is displayed in the title bar next to the AT&T 3G/Wifi Antenna icons, suggesting something in the background is doing a network search that's locking then entire foreground process.
I've attempted to:
1) hard reset the device,
2) restore from a backup of 5.1 (doesn't have the aforementioned problem) and reinstall the 5.1.1 update (has the problem)
3) swear at it and curse Steve Job's mock-turtleneck for allowing such a peice of **** bug to exist (even if it's not his fault ex post homine)
Any further help would be great... I may end up downgrading to 5.1 just to not have to deal with this perpetual headache.
Thanks,
Etienne

I'm having the same issue. Phone started to degrade after update to 5.1.1 I have restarted, reset and restored from backup. I haven't tried to restore as new, as I'm not sure what the impact will be in my need to reset my corporate exchange e-mail, etc.
I see from many posts on other boards this is not isolated and is impacting many users. I'm using verizon as a the cell carrier.
My phone is warm and eating battery at a rate of 10% per half an hour in standby mode. No new apps or anything else of that nature.
Tinus Barnard wrote:
Will they fix this?

Linux vm hangs during snapshot hyper-V manager

Hi Experts,
I am using a custom linux VM having 8GB RAM an 4vCPUS on Windows Server 2008 R2 Hyper-V. The Linux Integration Services version is 3.4.
When I take snapshot of my Linux VM using Hyper-V manager, the VM hangs for 10-15 seconds. I cannot do any operations during this time.
After that the Snapshot succeeds, it is working fine.
This behavior is not seen in Win Server 2012 Hyper-V.
Anyone have inputs on why it is hanging?
Thanks in advance,
Saleem

That is expected.
VSS support for Linux is only available in 2012 r2
2008 r2 does a save -> backup -> restore
Hence the pause you see. If you check hyperv manager during this time you should see saving/restoring on the vm in question.
I get around it by setting my backup say 1am in the morning when no one will notice but this may not be acceptable for you in which case your only option would be to upgrade the host.
Thanks
Mike

Lightroom - allow multi-select when creating snapshots

When I make a load of changes to files for a particular job I like to make snapshots of the "Released Version" of each file so that I can go back to it later if I wish.
However, currently this means going into Develop for each file in turn, hitting "Create Snapshot" and then typing (or pasting) in the snapshot name. This is OK for a couple of files, but when you have 10, 20, 30 or more it's a major pain in the backside!
My suggestion therefore is to add "Create Snapshot" to a menu in the Library module and allowing users to create snapshots (with the same name) for ALL selected files in one operation. This would save a lot of time when working on batches.
Thanks!

I look at LR this way, right or wrong.
The Library module is like Bridge.
The Develop module IS ACR.
There are things you can't do in Bridge or the Library module of LR that you can do in Adobe Camera Raw. Making a snapshot of the current image being edited is one of them.
Have you tried selecting multiple images in the Film Strip part of the Develop module and then trying to create a snapshot of all of them?
You could also create a Virtual Copy of the images you plan on editing and editing those VCs to leave the original, REAL, image as it was taken.

PCA_C01 data selection hangs because of 0CHRT_ACCTS

WHen selecting data from 0PCA_C01 using listcube, the systems hangs without any display of results. I figured out that, it is happening only because of 0CHRT_ACCTS. In particular, it is because of /BIC/SCHRT_ACCTS table corruption. I tried RSRV and it did not help as it hanged at 'COMPARE NUMBER RANGE AT SID CHARACTERISTIC'.
I also tried to use RSDMD_CHECKPRG_ALL/RSDMD_SID_P_Q_REPAIR. This also did not help.
This works fine in production and DEV environments and only hangs in test environment.
Please advise on how to fix this problem.
Thanks,
RR

WHen selecting data from 0PCA_C01 using listcube, the systems hangs without any display of results. I figured out that, it is happening only because of 0CHRT_ACCTS. In particular, it is because of /BIC/SCHRT_ACCTS table corruption. I tried RSRV and it did not help as it hanged at 'COMPARE NUMBER RANGE AT SID CHARACTERISTIC'.
I also tried to use RSDMD_CHECKPRG_ALL/RSDMD_SID_P_Q_REPAIR. This also did not help.
This works fine in production and DEV environments and only hangs in test environment.
Please advise on how to fix this problem.
Thanks,
RR

SELECT hangs despite Snapshot Isolation

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