RLE-aware optimization of SQL queries

A computer program product, encoded on one or more non-transitory computer storage media, comprising instructions that when executed by one or more computers cause the one or more computers to perform operations comprising:

• receiving, by a distributed database system, a first query plan for computing query results from a database having compressed data, wherein the first query plan includes one or more first decompress operators that are applied to data in compressed form to generate data in decompressed form, wherein the first query plan specifies that the one or more first decompress operators are executed before a particular operator;
• determining that the first query plan is logically equivalent to a second query plan that has a second decompress operator instead of the one or more first decompressor operators, wherein the second query plan specifies that the second decompressor operator is executed after the particular operator;
• and
• in response, obtaining query results from the database using the second query plan instead of the first query plan.

A distributed database system comprising:

• one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:
• receiving, by the distributed database system, a first query plan for computing query results from a database having compressed data, wherein the first query plan includes one or more first decompress operators that are applied to data in compressed form to generate data in decompressed form, wherein the first query plan specifies that the one or more first decompress operators are executed before a particular operator;
• determining that the first query plan is logically equivalent to a second query plan that has a second decompress operator instead of the one or more first decompressor operators, wherein the second query plan specifies that the second decompressor operator is executed after the particular operator;
• and
• in response, obtaining query results from the database using the second query plan instead of the first query plan.