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fix(postgresql): Make pg error clear with table name #5733

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fix(postgresql): Make pg error clear with table name #5733

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1b99799
fix(postgresql): Make pg error clear with table name
yevgenypats Dec 17, 2022
21421e2
fix lint
yevgenypats Dec 17, 2022
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59 changes: 43 additions & 16 deletions plugins/destination/postgresql/client/write.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2,15 +2,13 @@ package client

import (
"context"
"errors"
"fmt"
"strings"
"sync/atomic"

"github.com/cloudquery/plugin-sdk/plugins"
"github.com/cloudquery/plugin-sdk/schema"
"github.com/cloudquery/plugin-sdk/specs"
"github.com/jackc/pgconn"
"github.com/jackc/pgtype"
"github.com/jackc/pgx/v4"
)
Expand All @@ -21,9 +19,35 @@ var cqStatusToPgStatus = map[schema.Status]pgtype.Status{
schema.Present: pgtype.Present,
}

// Postgres best performance for CQ per our benchmark is achieved with batch that includes different tables
// given we can't predict how many objects will be in each table.
// This is why if we encounter an error we can't know which object/table caused and related the error to the object
// we we need to find the error and exit/stop the sync.
// Also, it is not advice to split the batch into different tables (for postgresql) as
// this will mean increased number of goroutines and will mean more connections which PostgreSQL is not great with.
// Also, I've benchmarked CopyFrom and batch and seems there is no significant difference in CQ case.
// maybe in the future we can provide a flag to switch batching mechanism.
func (c *Client) findErrorInBatch(ctx context.Context, items []*batchItem) error {
for _, item := range items {
_, err := c.conn.Exec(ctx, item.sql, item.arguments...)
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@erezrokah erezrokah Dec 18, 2022

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Are queries guaranteed to behave the same the second time we execute them? I'm concerned this can generated unrelated errors

if err != nil {
return fmt.Errorf("failed to insert into table %s with sql %s: %w", item.table, item.sql, err)
}
}
return nil
}

type batchItem struct {
table string
sql string
arguments []interface{}
}

func (c *Client) Write(ctx context.Context, tables schema.Tables, res <-chan *plugins.ClientResource) error {
var sql string
batch := &pgx.Batch{}
batchItems := make([]*batchItem, 0, c.batchSize)
// resources :=

for r := range res {
table := tables.Get(r.TableName)
Expand All @@ -35,35 +59,38 @@ func (c *Client) Write(ctx context.Context, tables schema.Tables, res <-chan *pl
} else {
sql = c.upsert(table)
}

batchItems = append(batchItems, &batchItem{
table: r.TableName,
sql: sql,
arguments: r.Data,
})
batch.Queue(sql, r.Data...)
if batch.Len() >= c.batchSize {
br := c.conn.SendBatch(ctx, batch)
if err := br.Close(); err != nil {
var pgErr *pgconn.PgError
if !errors.As(err, &pgErr) {
// not recoverable error
return fmt.Errorf("failed to execute batch: %w", err)
if batchErr := br.Close(); batchErr != nil {
if err := c.findErrorInBatch(ctx, batchItems); err != nil {
return err
}
atomic.AddUint64(&c.metrics.Errors, 1)
c.logger.Error().Err(pgErr).Str("table", pgErr.TableName).Msg("failed to execute batch with pgerror")
return fmt.Errorf("failed to execute batch and was unable to pinpoint table: %w", batchErr)
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@erezrokah erezrokah Dec 18, 2022

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Doesn't this mean everything was successfully inserted? Maybe log it and not return an error

}
atomic.AddUint64(&c.metrics.Writes, uint64(c.batchSize))
batch = &pgx.Batch{}
batchItems = make([]*batchItem, 0, c.batchSize)
}
}

if batch.Len() > 0 {
br := c.conn.SendBatch(ctx, batch)
if err := br.Close(); err != nil {
var pgErr *pgconn.PgError
if !errors.As(err, &pgErr) {
// no recoverable error
return fmt.Errorf("failed to execute batch: %w", err)
if batchErr := br.Close(); batchErr != nil {
if err := c.findErrorInBatch(ctx, batchItems); err != nil {
return err
}
// this should never happen
return fmt.Errorf("failed to execute batch and was unable to pinpoint table: %w", batchErr)
}
c.logger.Error().Err(pgErr).Str("table", pgErr.TableName).Msg("failed to execute batch with pgerror")
}
atomic.AddUint64(&c.metrics.Writes, uint64(c.batchSize))
atomic.AddUint64(&c.metrics.Writes, uint64(batch.Len()))
}

return nil
Expand Down