ns::stats::SQLiteHistory method history allocator (public)

 <instance of ns::stats::SQLiteHistory> history allocator \
    -from from  -to to  [ -limit limit ] [ -cursor cursor ]

Defined in

Read compact process-wide allocator history from the configured owner server using one bounded sample SELECT. New samples provide stored projections; old rows without a projection are decoded once in this read. No topology loading or full-window payload rescan is performed. Preserve missing gauges as absent dictionary keys. Timestamps are epoch microseconds; instance and intervalSeconds allow callers to preserve restart boundaries and gaps. Reading does not collect or write samples. Coverage complete and windowExamined remain false: this projection does not certify window boundaries or absence of eviction/write failures. Use history query when full-window coverage assessment is required. Timings distinguish checkout, sample SQL read, decoding and total time.

Switches:

-from (required, integer)

Inclusive lower bound in epoch seconds; must be nonnegative.

-to (required, integer)

Exclusive upper bound in epoch seconds; after from, at most 24 hours later and no later than now.

-limit (optional, integer, defaults to "10000")

Maximum compact records per page, 1..10000; default 10000.

-cursor (optional, integer, defaults to "0")

Nonnegative timestamp cursor in microseconds, default 0; pass nextCursor unchanged for continuation.

Returns:

Dictionary containing compact records (timestamp, instance, sampling.intervalSeconds and memory), more, nextCursor, legacyDecoded, timings in milliseconds and conservative coverage metadata.

Testcases:

No testcase defined.

Source code:

set started [clock microseconds]
if {$from < 0 || $to <= $from || $to-$from > 86400 || $to > [clock seconds]
    || $limit < 1 || $limit > 10000 || $cursor < 0} {
    error "expected an epoch window up to 24 hours, limit 1..10000 and nonnegative cursor"
}
set config [nsv_get ns_stats history]
if {$config eq ""} {error "history is not configured"}
if {[dict get $config owner] ne [ns_info server]} {error "query history from its configured owner server"}
set db [:historyConnect $config]
set checkedOut [clock microseconds]
set transaction false
try {
    :sql $db {BEGIN}
    set transaction true
    set columns [lmap row [:sql $db {SELECT name FROM pragma_table_info('ns_stats_samples')}] {dict get $row name}]
    if {"allocator" in $columns} {
        set projection {coalesce(allocator,'') AS allocator,CASE WHEN allocator IS NULL THEN payload ELSE '' END AS legacy}
    } else {
        set projection {'' AS allocator,payload AS legacy}
    }
    set low [expr {$from*1000000}]; set high [expr {$to*1000000}]
    set beforeRead [clock microseconds]
    set rows [:sql $db "SELECT at,instance,$projection FROM ns_stats_samples WHERE at >= $low AND at < $high AND at > $cursor ORDER BY at LIMIT [expr {$limit+1}]"]
    set afterRead [clock microseconds]
    set more [expr {[llength $rows]>$limit}]
    set records {}; set legacy 0
    foreach row [lrange $rows 0 [expr {$limit-1}]] {
        if {[dict get $row allocator] eq ""} {
            set point [:allocatorPoint [:unpack [dict get $row legacy]]]
            incr legacy
        } else {
            set point [dict get $row allocator]
        }
        lappend records $point
    }
    set decoded [clock microseconds]
    :sql $db {COMMIT}
    set transaction false
    return [dict create schemaVersion 1 source sqlite projection allocator from $from to $to  records $records more $more nextCursor [expr {$more ? [dict get [lindex $rows $limit-1] at] : ""}]  legacyDecoded $legacy coverage [dict create complete false windowExamined false  incompleteReasons [expr {$more ? {allocator-projection-not-certified more-pages} : {allocator-projection-not-certified}}]]  timings [dict create checkoutMs [expr {($checkedOut-$started)/1000.0}]  readMs [expr {($afterRead-$beforeRead)/1000.0}] decodeMs [expr {($decoded-$afterRead)/1000.0}]  totalMs [expr {([clock microseconds]-$started)/1000.0}]]]
} finally {
    if {$transaction} {catch {:sql $db {ROLLBACK}}}
    ns_db releasehandle $db
}

XQL Not present:

Generic, PostgreSQL, Oracle