[ https://issues.apache.org/jira/browse/CALCITE-3786?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17136547#comment-17136547 ]
Stamatis Zampetakis commented on CALCITE-3786: ---------------------------------------------- Hey [~danny0405] thanks for working on this. For the moment I am not going to comment on the approach will do that later if there are still disagreements. In the meantime, multiple people have requested to wait a bit and not commit the PR yet so I find it fair to revert the commit for the time being. I know that you have spent quite some time on it but reviewers are also investing their own. We are not in a rush to get a release out so I don't see a big problem keeping this off-master a bit more. > Add Digest interface to enable efficient hashCode(equals) for RexNode and > RelNode > --------------------------------------------------------------------------------- > > Key: CALCITE-3786 > URL: https://issues.apache.org/jira/browse/CALCITE-3786 > Project: Calcite > Issue Type: New Feature > Components: core > Affects Versions: 1.21.0 > Reporter: Vladimir Sitnikov > Assignee: Danny Chen > Priority: Major > Fix For: 1.24.0 > > Time Spent: 4h 40m > Remaining Estimate: 0h > > Current digests for RexNode, RelNode, RelType, and similar cases use String > concatenation. > It is easy to implement, however, it has drawbacks: > 1) String objects cannot be reused. For instance, RexCall has operands, > however, the digest is duplicated. It causes extra memory use and extra CPU > for string copying > 2) There's no way to have multiple #toString() methods. RelType might need > multiple digests: "including field names", "excluding field names". > A suggested resolution might be behind the lines of > {code:java} > class Digest { // immutable > final int hashCode; // speedup hashCode and equals > final Object[] contents; // The values are either other Digest objects or > Strings > String toString(); // e.g. for debugging purposes > int compareTo(Digest); // e.g. for debugging purposes. > } > {code} > Note how fields in Kotlin are aligned much better, and it makes it easier to > read: > {code:java} > class Digest { // immutable > val hashCode: Int // speedup hashCode and equals > val contents: Array<Any> // The values are either other Digest objects or > Strings > fun toString(): String // e.g. for debugging purposes > fun compareTo(other: Digest): Int // e.g. for debugging purposes. > } > {code} > Then the digest for RexCall could be the bits relevant to RexCall itself + > digests of the operands (which can be reused as is) -- This message was sent by Atlassian Jira (v8.3.4#803005)