$hist_query_overflow_n

The $hist_query_overflow_n table stores the remaining characters of the query string that was stored in the querytext column of the $hist_query_prolog_n table.

For performance reasons, each row of this table stores approximately 8 KB of the query string; if the query text overflow cannot fit in one 8 KB row, the table uses multiple rows that are linked by sequenceid to store the entire query string.

Table 1. $hist_query_overflow_n
Name Type Description
npsid integer This value along with the instance ID (npsInstanceId) and operation ID (opid) form the foreign key into the operation table.
npsinstanceid integer Instance ID of the source system.
opid bigint Operation ID. Used as a foreign key from query epilog, overflow and plan, table, column access tables to query prolog.
logentryid bigint This ID and the NPS ID (npsid) and instance ID (npsinstanceid) form:
  • A foreign key into the hist_log_entry_n table
  • A primary key for this table
sessionid bigint Session ID. This ID and the NPS ID (npsid) and instance ID (npsinstanceid) form the foreign key from query, plan, table, and column access tables into session tables.
sequenceid integer This ID is the sequence ID of each entry. There is one for each query text fragment. The first overflow record has sequenceid 0.
next integer This is the pointer to next ID record (the next 8-KB portion of the querytext) in the sequence. The last record has a next value of -1.
querytext nvarchar(8192) Up to 8 KB of the overflow part of the query string.