firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package postgres

import "database/sql"

func (p *Postgres) doQueryColumns() error {
    if err := p.doDBQueryColumns(p.db); err != nil {
        p.Warning(err)
    }
    for _, conn := range p.dbConns {
        if conn.db == nil {
            continue
        }
        if err := p.doDBQueryColumns(conn.db); err != nil {
            p.Warning(err)
        }
    }
    return nil
}

func (p *Postgres) doDBQueryColumns(db *sql.DB) error {
    q := queryColumnsStats()

    for _, m := range p.mx.tables {
        if m.nullColumns != nil {
            m.nullColumns = newInt(0)
        }
    }

    var dbname, schema, table string
    var nullPerc int64
    return p.doDBQuery(db, q, func(column, value string, rowEnd bool) {
        switch column {
        case "datname":
            dbname = value
        case "schemaname":
            schema = value
        case "relname":
            table = value
        case "null_percent":
            nullPerc = parseInt(value)
        }
        if !rowEnd {
            return
        }
        if nullPerc == 100 && p.hasTableMetrics(table, dbname, schema) {
            v := p.getTableMetrics(table, dbname, schema)
            if v.nullColumns == nil {
                v.nullColumns = newInt(0)
            }
            *v.nullColumns++
        }
    })
}