wombatu-kun commented on code in PR #19495:
URL: https://github.com/apache/hudi/pull/19495#discussion_r3708886274
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hudi-trino/src/main/java/io/trino/plugin/hudi/util/PrefilledColumnValues.java:
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@@ -108,6 +113,24 @@ public Block toRleBlock(HiveColumnHandle columnHandle, int
positionCount)
}
private Object nativeValueOf(HiveColumnHandle columnHandle)
+ {
+ // Every input to computeNativeValue() is a constant of the split, but
appendTo is called once per
+ // prefilled column per record, and computing re-parses the partition
string each time
+ // ($file_modified_time even formats a timestamp and parses it
straight back). Memoize per column so
+ // each one is resolved once per split. Keyed on the name rather than
the handle because
+ // HiveColumnHandle.hashCode hashes seven fields through a varargs
array, whereas a String caches
+ // its hash. containsKey rather than a null check: null is a
legitimate resolved value, both for
+ // the hive-null convention and for the lenient fallback below.
+ String name = columnHandle.getName();
+ if (resolvedValues.containsKey(name)) {
Review Comment:
`containsKey` then `get` is two hash lookups per record per prefilled column
on the `buildRecordInPage` path. A sentinel plus `getOrDefault` collapses it to
one - follow-up, not a blocker.
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