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erikdarlingdataclaude
erikdarlingdata
and
claude
authored
Add check 9: top blocking queries by wait time impact (#760)
Surfaces which queries caused the most blocking damage by extracting the blocker's sql_handle from the execution stack and summing the wait time inflicted on blocked sessions. Groups by (database, sql_handle, statement offsets), deduplicates across monitor loops via MAX per victim transaction, and reports each query's percentage of total blocking wait time. Only queries responsible for >= 10% of total are shown. Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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‎sp_HumanEvents/sp_HumanEventsBlockViewer.sql‎

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@@ -3555,6 +3555,233 @@ BEGIN
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b.host_name
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OPTION(RECOMPILE);
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IF @debug = 1
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BEGIN
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RAISERROR('Inserting #block_findings, check_id 9', 0, 1) WITH NOWAIT;
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END;
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WITH
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blocker_waits AS
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(
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SELECT
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b.database_name,
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query_text_pre =
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b.query_text_pre,
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b.transaction_id,
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sql_handle =
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CONVERT
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(
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varbinary(64),
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b.blocked_process_report.value
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(
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'(/event/data/value/blocked-process-report/blocking-process/process/executionStack/frame[not(@sqlhandle = "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")]/@sqlhandle)[1]',
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'varchar(130)'
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),
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1
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),
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stmtstart =
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ISNULL
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(
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b.blocked_process_report.value
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(
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'(/event/data/value/blocked-process-report/blocking-process/process/executionStack/frame[not(@sqlhandle = "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")]/@stmtstart)[1]',
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'integer'
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),
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0
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),
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stmtend =
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ISNULL
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(
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b.blocked_process_report.value
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(
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'(/event/data/value/blocked-process-report/blocking-process/process/executionStack/frame[not(@sqlhandle = "0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000")]/@stmtend)[1]',
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'integer'
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),
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-1
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),
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wait_time_ms =
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ISNULL
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(
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b.blocked_process_report.value
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(
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'(/event/data/value/blocked-process-report/blocked-process/process/@waittime)[1]',
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'bigint'
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),
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0
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)
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FROM #blocks AS b
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WHERE b.activity = 'blocking'
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AND (b.database_name = @database_name
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OR @database_name IS NULL)
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AND (b.contentious_object = @object_name
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OR @object_name IS NULL)
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),
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blocker_per_victim AS
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(
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SELECT
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bw.database_name,
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bw.sql_handle,
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bw.stmtstart,
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bw.stmtend,
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bw.query_text_pre,
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bw.transaction_id,
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wait_time_ms =
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MAX(bw.wait_time_ms)
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FROM blocker_waits AS bw
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WHERE bw.sql_handle IS NOT NULL
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GROUP BY
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bw.database_name,
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bw.sql_handle,
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bw.stmtstart,
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bw.stmtend,
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bw.query_text_pre,
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bw.transaction_id
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)
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INSERT
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#block_findings
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(
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check_id,
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database_name,
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object_name,
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finding_group,
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finding,
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sort_order
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)
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SELECT
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check_id =
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9,
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bpv.database_name,
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object_name =
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LEFT
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(
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REPLACE
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(
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REPLACE
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(
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ISNULL
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(
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MAX(bpv.query_text_pre),
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N'[Unknown]'
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),
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NCHAR(13),
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N' '
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),
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NCHAR(10),
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N' '
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),
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200
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),
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finding_group =
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N'Top Blocking Query',
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finding =
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N'This query caused ' +
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CONVERT
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(
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nvarchar(30),
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(
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SUM
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(
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CONVERT
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(
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bigint,
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bpv.wait_time_ms
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)
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) / 1000 / 86400
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)
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) +
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N' ' +
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CONVERT
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(
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nvarchar(30),
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DATEADD
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(
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SECOND,
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(
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SUM
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(
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CONVERT
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(
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bigint,
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bpv.wait_time_ms
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)
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) / 1000 % 86400
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),
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'19000101'
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),
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14
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) +
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N' of blocking wait time (' +
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ISNULL
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(
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CONVERT
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(
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nvarchar(10),
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CONVERT
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(
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decimal(5, 1),
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100.0 *
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SUM
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(
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CONVERT
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(
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bigint,
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bpv.wait_time_ms
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)
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) /
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NULLIF
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(
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SUM
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(
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SUM
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(
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CONVERT
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(
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bigint,
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bpv.wait_time_ms
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)
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)
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) OVER (),
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0
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)
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)
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),
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N'0.0'
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) +
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N'% of total) across ' +
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CONVERT
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(
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nvarchar(20),
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COUNT_BIG(DISTINCT bpv.transaction_id)
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) +
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N' blocked sessions.',
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sort_order =
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ROW_NUMBER() OVER
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(
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ORDER BY
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SUM
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(
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CONVERT
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(
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bigint,
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bpv.wait_time_ms
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)
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) DESC
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)
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FROM blocker_per_victim AS bpv
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GROUP BY
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bpv.database_name,
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bpv.sql_handle,
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bpv.stmtstart,
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bpv.stmtend
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HAVING
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SUM(CONVERT(bigint, bpv.wait_time_ms)) * 10 >=
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(
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SELECT
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SUM(CONVERT(bigint, bpv2.wait_time_ms))
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FROM blocker_per_victim AS bpv2
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)
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OPTION(RECOMPILE);
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IF @debug = 1
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BEGIN
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RAISERROR('Inserting #block_findings, check_id 1000', 0, 1) WITH NOWAIT;

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