Updating of in-memory synopsis metadata for inserts in database table

A method for updating a synopsis table for inserts in a base table stored in a storage medium comprised in a database system, the storage medium further storing the synopsis table, the database system further comprising a memory and a database management unit for implementing the method comprising:

• performing an insert transaction to insert at least one row in a given section of the base table;
• determining whether a synopsis entry for the given section of the base table is stored in the memory;
• in response to determining that the synopsis entry for the given section of the base table is stored in the memory:
• retrieving the in-memory synopsis entry for the given section of the base table;
• and
• updating metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• in response to determining that the synopsis entry for the given section of the base table is not stored in the memory:
• generating the in-memory synopsis entry for the given section of the base table;
• reading a synopsis entry row count stored in base table metadata of the base table, the synopsis entry row count indicating a number of rows in the given section of the base table covered by the in-memory synopsis entry;
• determining that the in-memory synopsis entry has missing data based on the synopsis entry row count;
• regenerating the missing data of the in-memory synopsis entry by scanning the given section of the base table;
• updating the metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• and
• incrementing the synopsis entry row count in the base table metadata in the memory.

A computer program product for updating a synopsis table for inserts in a base table stored in a storage medium comprised in a database system, the storage medium further storing the synopsis table, computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the database system to perform a method comprising:

• performing an insert transaction to insert at least one row in a given section of the base table;
• determining whether a synopsis entry for the given section of the base table is stored in a memory of the database system;
• in response to determining that the synopsis entry for the given section of the base table is stored in the memory:
• retrieving the in-memory synopsis entry for the given section of the base table;
• and
• updating metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• in response to determining that the synopsis entry for the given section of the base table is not stored in the memory:
• generating the in-memory synopsis entry for the given section of the base table;
• reading a synopsis entry row count stored in base table metadata of the base table, the synopsis entry row count indicating a number of rows in the given section of the base table covered by the in-memory synopsis entry;
• determining that the in-memory synopsis entry does not have missing data based on the synopsis entry row count;
• updating the metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• and
• incrementing the synopsis entry row count in the base table metadata.

A computer program product for updating a synopsis table for inserts in a base table stored in a storage medium comprised in a database system, the storage medium further storing the synopsis table, computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the database system to perform a method comprising:

• performing an insert transaction to insert at least one row in a given section of the base table;
• determining whether a synopsis entry for the given section of the base table is stored in a memory of the database system;
• in response to determining that the synopsis entry for the given section of the base table is stored in the memory:
• retrieving the in-memory synopsis entry for the given section of the base table;
• and
• updating metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• in response to determining that the synopsis entry for the given section of the base table is not stored in the memory:
• generating the in-memory synopsis entry for the given section of the base table;
• reading a synopsis entry row count stored in base table metadata of the base table, the synopsis entry row count indicating a number of rows in the given section of the base table covered by the in-memory synopsis entry;
• determining that the in-memory synopsis entry has missing data based on the synopsis entry row count;
• regenerating the missing data of the in-memory synopsis entry by scanning the given section of the base table;
• updating the metadata values in the in-memory synopsis entry for the given section of the base table with data from the at least one row being inserted into the base table;
• and
• incrementing the synopsis entry row count in the base table metadata.