diff options
Diffstat (limited to 'src/backend/access/gin')
| -rw-r--r-- | src/backend/access/gin/ginpostinglist.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/src/backend/access/gin/ginpostinglist.c b/src/backend/access/gin/ginpostinglist.c index 6337b1a8fce..e6d7c1a0788 100644 --- a/src/backend/access/gin/ginpostinglist.c +++ b/src/backend/access/gin/ginpostinglist.c @@ -23,7 +23,7 @@ /* * For encoding purposes, item pointers are represented as 64-bit unsigned * integers. The lowest 11 bits represent the offset number, and the next - * lowest 32 bits are the block number. That leaves 17 bits unused, ie. + * lowest 32 bits are the block number. That leaves 17 bits unused, i.e. * only 43 low bits are used. * * These 43-bit integers are encoded using varbyte encoding. In each byte, @@ -51,16 +51,16 @@ * Removing number is actually replacement of two numbers with their sum. We * have to prove that varbyte encoding of a sum can't be longer than varbyte * encoding of its summands. Sum of two numbers is at most one bit wider than - * than the larger of the summands. Widening a number by one bit enlarges its - * length in varbyte encoding by at most one byte. Therefore, varbyte encoding - * of sum is at most one byte longer than varbyte encoding of larger summand. - * Lesser summand is at least one byte, so the sum cannot take more space than - * the summands, Q.E.D. + * the larger of the summands. Widening a number by one bit enlarges its length + * in varbyte encoding by at most one byte. Therefore, varbyte encoding of sum + * is at most one byte longer than varbyte encoding of larger summand. Lesser + * summand is at least one byte, so the sum cannot take more space than the + * summands, Q.E.D. * * This property greatly simplifies VACUUM, which can assume that posting * lists always fit on the same page after vacuuming. Note that even though * that holds for removing items from a posting list, you must also be - * careful to not cause expansion e.g when merging uncompressed items on the + * careful to not cause expansion e.g. when merging uncompressed items on the * page into the compressed lists, when vacuuming. */ |