Could not continue scan with NOLOCK due to data movement error


A work around could be implementing fix 4228 but this will mean that you will lose context data in some cases, but most of the time it will be okay. Not hotfix currently available for this. Raise a CSS case with microsoft. What’s probably the root cause of this error: “SQL BLOB fields in combination with the NOLOCK query hint.“ Because BLOB fields can store big data amount (>8kb) it uses (in default) a pointer to store this data as a stream outside the table page. Due to this pointer construction the reading (select) of a blob field will be in streaming mode. During this stream the error handling is not the same as by normal sql fields. Due to this we get if a blob field is changed during the read process (to the console example when a alert view is refreshed) SQL server will close the stream and generate the NOLOCK error. (if you use the NOLOCK hint) In the console the Alert views use 2 functions that use the NOLOCK hint and 2 blob fields. (context,alertparams) So when the alert context is changed during a console alert view refresh we will get this error. (see also in table below) The impact isn’t very big, you will lose no data in our ops db. But however clicking away the console error can be annoying. Most of the time this will hit SCOM environments that are big and having a lot of monitors with state changes/sec that generate an alert. Resolutions: (Not Reccommended) -Tune this scom monitors to minimize the state changes. -Set the refresh rate of the operator console to 120sec or bigger -Implement the 4228 fix. (this will not update the context field anymore, so solving the problem. But in some cases you will lose context data of the alert. Don’t worry you can see this back in the health explorer.) – Change the way the blob fields are used. I’ve some ideas on this but this will be up to the SCOM dev team. See below:
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