split BQ merge statements and run them individually #1038
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serprex
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Jan 9, 2024
serprex
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Jan 9, 2024
serprex
reviewed
Jan 9, 2024
serprex
reviewed
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flow/connectors/utils/array.go
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| @@ -16,3 +16,15 @@ func ArrayMinus(first []string, second []string) []string { | |||
| } | |||
| return result | |||
| } | |||
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| func ArrayChunksGen[T any](slice []T, size int) [][]T { | |||
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Suggested change
| func ArrayChunksGen[T any](slice []T, size int) [][]T { | |
| func ArrayChunks[T any](slice []T, size int) [][]T { |
serprex
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For tables with a lot of columns in general and especially many toast columns, some batches can trigger a MERGE statement so complex that BigQuery is unable to process them, with errors like
The query is too large. The maximum standard SQL query length is 1024.00K characters, including comments and white space characters.Error 400: Resources exceeded during query execution: The query is too complex., resourcesExceededFor now, the fix is splitting these complex MERGE statements into smaller ones that act on different subsets of a raw table [partitioning on the basis of
_peerdb_unchanged_toast_columns]. This can lead to tables need 10+ MERGE statements in a single batch, but this is a compromise with our current design. Instead of sending MERGEs for all tables at once, we do it per table now and update metadata at the end, to avoid exceeding SQL query length limits.