mco_stat_histogram_get

RT

Retrieve a pointer to a specific histogram by its internal index.

Prototype

    MCO_RET mco_stat_histogram_get(
        /*IN*/  mco_stat_hdl hist_idx,
        /*OUT*/ mco_stat_histogram_h *ret_hist
    );

Arguments

Description

This function provides direct access to a histogram stored in the database's statistics memory region. It is typically used after obtaining a valid histogram index from mco_stat_get_histogram_source().

The returned pointer points to internal runtime data and remains valid as long as the database is open. The histogram contains distribution data (e.g., transaction durations) collected automatically when a counter with histogram support is updated.

Applications should not modify the histogram data directly. The structure is intended for read-only inspection (e.g., by monitoring tools or diagnostic utilities).

Note: The statistics subsystem must be initialized (i.e., a database with statistics support must be open) before calling this function.

Return Codes

Example

    mco_stat_hdl hist_idx;
    mco_stat_histogram_h hist;
    MCO_RET rc;

    // Assume we have a counter with histogram enabled
    rc = mco_stat_get_histogram_source(MCO_STATRT_MAX_TRANS_TIME, &hist_idx);
    if (rc == MCO_S_OK && hist_idx != MCO_STAT_INVALID_HANDLE) {
        rc = mco_stat_histogram_get(hist_idx, &hist);
        if (rc == MCO_S_OK) {
            printf("Histogram range: %u\n", hist->range);
            printf("Total samples: %u\n",
                hist->bars[0] + hist->bars[1] + ... ); // sum all bars
        }
    }

Files