Sorry if this is a bit obvious. I did not dive into your code. But I did notice that replacePositionalPlaceholders returns buf.String(). If you are certain that this is where the memory 'leak' is originating, then the most likely scenario is that the returned string is never being collected. Is it possible that somehow there is a reference being kept to the string, or an object containing the string?
On Sunday, August 30, 2020 at 11:25:15 AM UTC-4, Sarath Prabath Redlapalli Jaya wrote: > > Hi, we've been observing high memory usage in the following code > https://github.com/Masterminds/squirrel/blob/master/placeholder.go#L113 > > We measured from pprof of heap > > (pprof) top20 > > Showing nodes accounting for 360.07MB, 91.31% of 394.32MB total > > Dropped 142 nodes (cum <= 1.97MB) > > Showing top 20 nodes out of 139 > > flat flat% sum% cum cum% > > 101.21MB 25.67% 25.67% 101.21MB 25.67% bytes.(*Buffer).String > > 48.01MB 12.18% 37.84% 48.01MB 12.18% > github.com/newrelic/go-agent/v3/newrelic.(*spanAttributeMap).add > > 42.61MB 10.81% 48.65% 43.11MB 10.93% > github.com/newrelic/go-agent/v3/newrelic.(*txnTrace).witnessNode > > 38.54MB 9.77% 58.42% 38.54MB 9.77% > go.uber.org/zap/buffer.NewPool.func1 > > 19MB 4.82% 63.24% 19MB 4.82% > github.com/newrelic/go-agent/v3/newrelic.segmentEnd.spanEvent > > 16.51MB 4.19% 67.43% 91.04MB 23.09% > github.com/newrelic/go-agent/v3/newrelic.endDatastoreSegment > > 14.01MB 3.55% 70.98% 18.01MB 4.57% > github.com/newrelic/go-agent/v3/newrelic.newTxn > > 13.51MB 3.43% 74.41% 93.13MB 23.62% > github.com/newrelic/go-agent/v3/newrelic.endExternalSegment > > 12.01MB 3.05% 77.45% 12.01MB 3.05% > github.com/newrelic/go-agent/v3/newrelic.getStackTrace > > 10.51MB 2.66% 80.12% 10.51MB 2.66% > github.com/newrelic/go-agent/v3/newrelic.(*slowQueries).insertAtIndex > > 8MB 2.03% 82.15% 8MB 2.03% > github.com/newrelic/go-agent/v3/newrelic.newSlowQueries > > 6.51MB 1.65% 85.73% 6.51MB 1.65% > github.com/DataDog/datadog-go/statsd.newStatsdBuffer > > 4MB 1.01% 86.75% 52.01MB 13.19% > github.com/newrelic/go-agent/v3/newrelic.(*spanAttributeMap).addString > > 3.50MB 0.89% 87.64% 3.50MB 0.89% > go.uber.org/zap.(*Logger).clone > > 3.50MB 0.89% 88.52% 3.50MB 0.89% > github.com/newrelic/go-agent/v3/newrelic.externalMetricKey.scopedMetric > > 3MB 0.76% 89.28% 3MB 0.76% > github.com/newrelic/go-agent/v3/newrelic.addUserAttribute > > 3MB 0.76% 90.05% 3MB 0.76% strings.(*Builder).WriteString > > 2.50MB 0.63% 90.68% 6.06MB 1.54% encoding/json.Unmarshal > > 2.50MB 0.63% 91.31% 2.50MB 0.63% context.(*cancelCtx).Done > > ===== > > Resetting the buffer by defer didn't help either. So moved to string > builder like this > > func replacePositionalPlaceholders(sql, prefix string) (string, error) { > buf := &strings.Builder{} > defer buf.Reset() > > i := 0 > for { > p := strings.Index(sql, "?") > if p == -1 { > break > } > > if len(sql[p:]) > 1 && sql[p:p+2] == "??" { // escape ?? => ? > buf.WriteString(sql[:p]) > buf.WriteString("?") > if len(sql[p:]) == 1 { > break > } > sql = sql[p+2:] > } else { > i++ > buf.WriteString(sql[:p]) > fmt.Fprintf(buf, "%s%d", prefix, i) > sql = sql[p+1:] > } > } > > buf.WriteString(sql) > return buf.String(), nil > } > > ====== > > This didn't help either, from the results below > > (pprof) top20 > > Showing nodes accounting for 220.09MB, 90.37% of 243.55MB total > > Dropped 126 nodes (cum <= 1.22MB) > > Showing top 20 nodes out of 135 > > flat flat% sum% cum cum% > > 33.97MB 13.95% 13.95% 33.97MB 13.95% strings.(*Builder).Write > > 29.07MB 11.94% 25.89% 29.57MB 12.14% > github.com/newrelic/go-agent/v3/newrelic.(*txnTrace).witnessNode > > 28.01MB 11.50% 37.39% 28.01MB 11.50% > github.com/newrelic/go-agent/v3/newrelic.(*spanAttributeMap).add > > 24.34MB 9.99% 47.38% 24.34MB 9.99% strings.(*Builder).WriteString > > 18.52MB 7.60% 54.98% 18.52MB 7.60% > go.uber.org/zap/buffer.NewPool.func1 > > 11.01MB 4.52% 59.50% 60.59MB 24.88% > github.com/newrelic/go-agent/v3/newrelic.endExternalSegment > > 10.01MB 4.11% 63.61% 13.51MB 5.55% > github.com/newrelic/go-agent/v3/newrelic.newTxn > > 10MB 4.11% 67.72% 10MB 4.11% > github.com/newrelic/go-agent/v3/newrelic.segmentEnd.spanEvent > > 7MB 2.88% 73.73% 7MB 2.88% > github.com/newrelic/go-agent/v3/newrelic.(*slowQueries).insertAtIndex > > 7MB 2.88% 76.60% 50.02MB 20.54% > github.com/newrelic/go-agent/v3/newrelic.endDatastoreSegment > > 6.51MB 2.67% 79.28% 6.51MB 2.67% > github.com/DataDog/datadog-go/statsd.newStatsdBuffer > > 6MB 2.46% 81.74% 6.50MB 2.67% > github.com/newrelic/go-agent/v3/newrelic.addUserAttribute > > 5.50MB 2.26% 84.00% 5.50MB 2.26% > github.com/newrelic/go-agent/v3/newrelic.getStackTrace > > 3MB 1.23% 85.23% 3MB 1.23% > github.com/newrelic/go-agent/v3/newrelic.newSlowQueries > > 3MB 1.23% 86.47% 3MB 1.23% > go.uber.org/zap.(*Logger).clone > > 3MB 1.23% 87.70% 3MB 1.23% > github.com/newrelic/go-agent/v3/newrelic.externalMetricKey.scopedMetric > > 2.50MB 1.03% 88.72% 30.51MB 12.53% > github.com/newrelic/go-agent/v3/newrelic.(*spanAttributeMap).addString > > 2MB 0.82% 90.37% 2MB 0.82% encoding/hex.EncodeToString > > (pprof) peek Write > > Showing nodes accounting for 243.55MB, 100% of 243.55MB total > > ----------------------------------------------------------+------------- > > flat flat% sum% cum cum% calls calls% + context > > ----------------------------------------------------------+------------- > > 33.97MB 100% | fmt.Fprintf > > 33.97MB 13.95% 13.95% 33.97MB 13.95% | > strings.(*Builder).Write > > ----------------------------------------------------------+------------- > > 22.34MB 91.78% | > github.com/XXXXX/squirrel.replacePositionalPlaceholders > > 2MB 8.22% | > net/url.(*URL).String > > 24.34MB 9.99% 23.94% 24.34MB 9.99% | > strings.(*Builder).WriteString > > ----------------------------------------------------------+------------- > > 1.16MB 100% | > encoding/json.compact > > 0 0% 23.94% 1.16MB 0.48% | > bytes.(*Buffer).Write > > 1.16MB 100% | > bytes.(*Buffer).grow > > ----------------------------------------------------------+------------- > > 6.51MB 100% | > github.com/DataDog/datadog-go/statsd.New > > 0 0% 23.94% 6.51MB 2.67% | > github.com/DataDog/datadog-go/statsd.newWithWriter > > 6.51MB 100% | > github.com/DataDog/datadog-go/statsd.newBufferPool > > ----------------------------------------------------------+------------- > > 12.01MB 100% | > go.uber.org/zap.(*SugaredLogger).log > > 0 0% 23.94% 12.01MB 4.93% | > go.uber.org/zap/zapcore.(*CheckedEntry).Write > > 12.01MB 100% | > go.uber.org/zap/zapcore.(*ioCore).Write > > ----------------------------------------------------------+------------- > > 12.01MB 100% | > go.uber.org/zap/zapcore.(*CheckedEntry).Write > > 0 0% 23.94% 12.01MB 4.93% | > go.uber.org/zap/zapcore.(*ioCore).Write > > 12.01MB 100% | > go.uber.org/zap/zapcore.consoleEncoder.EncodeEntry > > ----------------------------------------------------------+------------- > > 1MB 100% | > golang.org/x/net/http2.(*Framer).readMetaFrame > > 0 0% 23.94% 1MB 0.41% | > golang.org/x/net/http2/hpack.(*Decoder).Write > > 1MB 100% | > golang.org/x/net/http2/hpack.(*Decoder).parseHeaderFieldRepr > > ----------------------------------------------------------+------------- > > (pprof) > > > Please help how to debug this more > > > Regards > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. 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