netdata/netdata

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

package postgres

import (
    "fmt"
)

func (p *Postgres) doQueryReplicationMetrics() error {
    if err := p.doQueryReplStandbyAppWALDelta(); err != nil {
        return fmt.Errorf("querying replication standby app wal delta error: %v", err)
    }

    if p.pgVersion >= pgVersion10 {
        if err := p.doQueryReplStandbyAppWALLag(); err != nil {
            return fmt.Errorf("querying replication standby app wal lag error: %v", err)
        }
    }

    if p.pgVersion >= pgVersion10 && p.isSuperUser() {
        if err := p.doQueryReplSlotFiles(); err != nil {
            return fmt.Errorf("querying replication slot files error: %v", err)
        }
    }

    return nil
}

func (p *Postgres) doQueryReplStandbyAppWALDelta() error {
    q := queryReplicationStandbyAppDelta(p.pgVersion)

    var app string
    return p.doQuery(q, func(column, value string, _ bool) {
        switch column {
        case "application_name":
            app = value
            p.getReplAppMetrics(app).updated = true
        default:
            // TODO: delta calculation was changed in https://github.com/netdata/netdata/go/go.d.plugin/pull/1039
            // - 'replay_delta' (probably other deltas too?) can be negative
            // - Also, WAL delta != WAL lag after that PR
            v := parseInt(value)
            if v < 0 {
                v = 0
            }
            switch column {
            case "sent_delta":
                p.getReplAppMetrics(app).walSentDelta += v
            case "write_delta":
                p.getReplAppMetrics(app).walWriteDelta += v
            case "flush_delta":
                p.getReplAppMetrics(app).walFlushDelta += v
            case "replay_delta":
                p.getReplAppMetrics(app).walReplayDelta += v
            }
        }
    })
}

func (p *Postgres) doQueryReplStandbyAppWALLag() error {
    q := queryReplicationStandbyAppLag()

    var app string
    return p.doQuery(q, func(column, value string, _ bool) {
        switch column {
        case "application_name":
            app = value
            p.getReplAppMetrics(app).updated = true
        case "write_lag":
            p.getReplAppMetrics(app).walWriteLag += parseInt(value)
        case "flush_lag":
            p.getReplAppMetrics(app).walFlushLag += parseInt(value)
        case "replay_lag":
            p.getReplAppMetrics(app).walReplayLag += parseInt(value)
        }
    })
}

func (p *Postgres) doQueryReplSlotFiles() error {
    q := queryReplicationSlotFiles(p.pgVersion)

    var slot string
    return p.doQuery(q, func(column, value string, _ bool) {
        switch column {
        case "slot_name":
            slot = value
            p.getReplSlotMetrics(slot).updated = true
        case "replslot_wal_keep":
            p.getReplSlotMetrics(slot).walKeep += parseInt(value)
        case "replslot_files":
            p.getReplSlotMetrics(slot).files += parseInt(value)
        }
    })
}