diff options
Diffstat (limited to 'app/services/help-service.ts')
| -rw-r--r-- | app/services/help-service.ts | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/app/services/help-service.ts b/app/services/help-service.ts index 8859c24..0195aff 100644 --- a/app/services/help-service.ts +++ b/app/services/help-service.ts @@ -12,11 +12,14 @@ export var NODE_DESCRIPTIONS = { "NESTED LOOP": `merges two record sets by looping through every record in the first set and trying to find a match in the second set. All matching records are returned.`, "MERGE JOIN": `merges two record sets by first sorting them on a <strong>join key</strong>.`, + "HASH": `generates a hash table from the records in the input recordset. Hash is used by + <strong>Hash Join</strong>.`, + "HASH JOIN": `joins to record sets by hashing one of them (using a <strong>Hash Scan</scan>).`, "AGGREGATE": `groups records together based on a GROUP BY or aggregate function (like <code>sum()</code>).`, "HASHAGGREGATE": `groups records together based on a GROUP BY or aggregate function (like sum()). Hash Aggregate uses a hash to first organize the records by a key.`, - "SEQ SCAN": `finds relevant records by sequentially scanning the table. Seq Scans perform a single read operation - (only the table is read).`, + "SEQ SCAN": `finds relevant records by sequentially scanning the input record set. When reading from a table, + Seq Scans (unlike Index Scans) perform a single read operation (only the table is read).`, "INDEX SCAN": `finds relevant records based on an <strong>Index</strong>. Index Scans perform 2 read operations: one to read the index and another to read the actual value from the table.`, "INDEX ONLY SCAN": `finds relevant records based on an <strong>Index</strong>. Index Only Scans perform a single read operation |